Abelisaurus comahuensis is the dinosaur that gave its name to the entire Abelisauridae family, one of the most successful predator groups of Gondwana. It lived during the Campanian stage of the Late Cretaceous, approximately 83 to 80 million years ago, in what is now Patagonia, Argentina. Known from a single partial skull discovered in 1983, it was a medium-sized bipedal theropod roughly 7.4 meters long and weighing about 1.5 metric tons. The skull, estimated at over 85 centimeters long, bears characteristic rough ridges and large fenestrae that reduced skull weight. Its more derived relatives, such as Carnotaurus and Majungasaurus, became far more famous, but it was Abelisaurus that opened the way for recognition of the entire lineage.

Cretaceous Carnivore 7.4m

US · 125–110 Ma

Acrocanthosaurus

Acrocanthosaurus atokensis

"High-spined lizard from Atoka"

Acrocanthosaurus atokensis was the largest terrestrial predator of Early Cretaceous North America. Measuring around 11 to 12 meters long and weighing up to 6 metric tons, it was distinguished by tall neural spines running along its back, forming a prominent muscular ridge. Its long, narrow skull housed recurved serrated teeth, and its forelimbs, though robust, had limited range of motion. It lived approximately 113 to 110 million years ago on the coastal plains of what is now the southern and central United States, hunting large sauropods and ornithopods. Its giant trackways preserved in Texas are direct evidence of its dominant presence.

Cretaceous Carnivore 11.5m

CA · 70–68 Ma

Albertosaurus

Albertosaurus sarcophagus

"Flesh-eating lizard of Alberta"

Albertosaurus sarcophagus was a medium-sized tyrannosaurid that lived during the late Campanian, 70 to 68 million years ago, in what is now the Canadian province of Alberta. At around 8 to 9 meters long and between 1,300 and 1,700 kg, it was smaller and more agile than its later relative Tyrannosaurus rex. It is distinguished by a relatively narrower skull, proportionally longer hindlimbs, and an estimated locomotor speed of 14 to 21 km/h. The discovery of a bonebed at Dry Island containing at least 26 individuals of different ages provided the strongest evidence of gregarious behavior among tyrannosaurids.

Cretaceous Carnivore 9m

US · 155–150 Ma

Allosaurus

Allosaurus fragilis

"Fragile different lizard"

Allosaurus fragilis was the apex predator of the Morrison Formation in the Late Jurassic, 155 to 150 million years ago. Up to 10.5 meters long and weighing around 2,300 kg, it was the largest carnivore in its ecosystem. Its skull was lightweight and highly fenestrated, reducing weight without sacrificing strength. Finite element analyses revealed the skull was designed to withstand vertical and horizontal tensile forces, suggesting a hatchet-style attack with the upper jaws rather than a simple closing bite. It had three fingers on each hand with curved claws up to 25 centimeters long. The Cleveland-Lloyd Quarry 9 in Utah has yielded over 10,000 Allosaurus bones, making it the best-sampled theropod in North America. It was the primary predator of juvenile sauropods, ornithopods, and stegosaurs.

Jurassic Carnivore 10.5m

AR · 129–122 Ma

Amargasaurus

Amargasaurus cazaui

"La Amarga lizard (honoring geologist Luis Cazau)"

Amargasaurus cazaui is one of the most recognizable sauropods of the Early Cretaceous, thanks to two parallel rows of extremely elongated neural spines running along its neck and back. Discovered in 1984 in the La Amarga Formation of Neuquén, Argentina, and described in 1991 by Leonardo Salgado and José Bonaparte, it is one of the best-preserved Early Cretaceous sauropod skeletons ever found. Measuring around 9 to 10 meters in length and approximately 2.6 metric tons, it was small for a sauropod, but its cervical spines, reaching up to 60 cm in height, made it unmistakable. Recent studies suggest these spines supported a skin sail, possibly used for thermoregulation or display.

Cretaceous Herbivore 10m

CN · 160.89–160.25 Ma

Anchiornis

Anchiornis huxleyi

"Near bird (of Huxley)"

Anchiornis huxleyi is one of the smallest and most completely known dinosaurs in science, living approximately 160 million years ago in what is now northeastern China. At just 34 cm long and weighing between 110 and 250 grams, it had four feathered wings: two on the forelimbs and two on the hindlimbs. It became the first Mesozoic dinosaur to have its complete coloration reconstructed from direct fossil evidence: a red head, black and gray body, and white wing feathers with black tips. Its phylogenetic position as a basal anchiornithid places it centrally in debates about the origin of avian flight.

Jurassic Carnivore 0.6m

US · 68–66 Ma

Ankylosaurus

Ankylosaurus magniventris

"Fused lizard with great belly"

Ankylosaurus magniventris was the largest known ankylosaurid, living at the end of the Cretaceous 68 to 66 million years ago in North America. At about 8 meters long and 6 metric tons, it was a quadrupedal herbivore equipped with a complete body armor: osteoderms fused to the skull, bony plates along the back and flanks, and a massive tail club capable of shattering predator bones. Its sideways-facing nostrils are unique among ankylosaurs. Despite its imposing size, it was rare in its ecosystem, likely inhabiting upland areas distant from river margins where hadrosaurs and ceratopsians lived.

Cretaceous Herbivore 8m

US · 67–66 Ma

Anzu

Anzu wyliei

"Wylie's winged demon"

Anzu wyliei is a large caenagnathid oviraptorosaur from the Late Cretaceous, Maastrichtian (about 67.2 to 66.0 Ma), collected in the Hell Creek Formation of North Dakota and South Dakota, United States. Reaching roughly 3.5 to 3.75 metres in length, about 1.5 metres at the hips and 200 to 300 kg in body mass, Anzu is one of the largest known caenagnathids and one of the largest North American oviraptorosaurs, in size only behind the giant Gigantoraptor erlianensis of Cretaceous China. The animal combines a rather peculiar set of features: a tall, delicate skull, toothless jaws sheathed in a horny beak (rhamphotheca), a pronounced sagittal crest atop the head, a long flexible neck, elongated arms ending in three-clawed hands, long slender running-adapted legs and a proportionally short tail. By phylogenetic inference it was almost certainly covered in feathers and bore remiges on the forelimbs, in line with the pattern documented for close relatives such as Caudipteryx, Avimimus and Gigantoraptor. It was discovered in 1998 by Fred Nuss and team on private land in South Dakota, and formally described in 2014 by Matthew C. Lamanna, Hans-Dieter Sues, Emma R. Schachner and Tyler R. Lyson in the open access journal PLoS ONE. The type material comprises three complementary specimens (CM 78000, CM 78001 and MRF 319) that together offer the most complete documentation of a North American caenagnathid to date, allowing much of the group's anatomy to be reconstructed for the first time. Thanks to the nickname 'Chicken from Hell', coined by the discoverers in reference to the apocalyptic late-Cretaceous setting, Anzu quickly became one of the most popular images in recent North American palaeontology, sharing Hell Creek with Tyrannosaurus rex, Triceratops, Edmontosaurus, Pachycephalosaurus and Dakotaraptor until the K-Pg mass extinction.

Cretaceous Omnivore 3.5m

US · 152–151 Ma

Apatosaurus

Apatosaurus ajax

"Deceptive lizard (Ajax, hero from Greek mythology)"

Apatosaurus ajax is the type species of the genus Apatosaurus, described by Othniel Charles Marsh in 1877 from bones discovered in Morrison, Colorado. One of the largest known diplodocids, it reached 21 to 22 meters in length and 16 to 22 tonnes. Its neck was notably more robust and thicker than those of its relatives Diplodocus and Brontosaurus, with ventrolaterally displaced cervical ribs. The species stood at the center of one of paleontology's greatest taxonomic controversies: the name Brontosaurus was considered its synonym for 112 years, until Tschopp, Mateus, and Benson (2015) demonstrated that Brontosaurus constitutes a distinct and valid genus.

Jurassic Herbivore 21m

BR · 113–108 Ma

Aratasaurus

Aratasaurus museunacionali

"Fire-born lizard (Museu Nacional)"

Aratasaurus museunacionali is a small basal coelurosaurian theropod from the Early Cretaceous (Albian, ~110 Ma) Romualdo Formation in the Araripe Basin, Santana do Cariri (Ceará, Brazil). Described by Juliana Sayão and colleagues in 2020, holotype MPSC R 2089 consists of an articulated right hindlimb (distal femur, proximal tibia, partial metatarsals, several phalanges and three unguals) of a juvenile individual aged around 4 years, estimated at 3.12 metres long and 34 kg. The name means 'lizard born from fire', referring to the fire at the Museu Nacional of Rio de Janeiro in September 2018, just before publication. Aratasaurus expands the known diversity of small theropods from the Araripe Basin, alongside Santanaraptor, Mirischia, Irritator and Angaturama, and is a rare basal coelurosaur from Gondwana.

Cretaceous Carnivore 3.12m

DE · 152–148 Ma

Archaeopteryx

Archaeopteryx lithographica

"Ancient wing from the lithographic stone"

Archaeopteryx lithographica is one of the most famous and important fossils in the history of science. It lived approximately 150 million years ago during the Late Jurassic, on the islands covering what is now the German state of Bavaria. About 0.5 meters long and estimated at half a kilogram, it was roughly the size of a raven. It combined features of theropod dinosaurs, including teeth, claws, and a long bony tail, with true feathers and wing asymmetry typical of modern flying birds. Thirteen specimens have been found in the Solnhofen Limestone, including the celebrated Berlin Exemplar, considered the most iconic transitional fossil between dinosaurs and birds.

Jurassic Carnivore 0.5m

AR · 97–93 Ma

Argentinosaurus

Argentinosaurus huinculensis

"Argentina lizard from Huincul"

Argentinosaurus huinculensis is arguably the largest land animal that ever lived, with length estimates between 30 and 35 meters and mass up to 80 tonnes. Discovered in 1987 in Neuquén, Argentine Patagonia, and formally described in 1993 by José Bonaparte and Rodolfo Coria, it belongs to the clade Lognkosauria, a group of giant titanosaurs exclusive to South America. Its fossil record is fragmentary: only a few dorsal vertebrae, ribs, and part of the sacrum have been found, yet they are sufficient to confirm its extraordinary size. It coexisted with the largest terrestrial predator of the Cretaceous, Giganotosaurus carolinii, in a fauna that continues to fascinate paleontologists worldwide.

Cretaceous Herbivore 33m

BE · 67–66.7 Ma

Wonderchicken

Asteriornis maastrichtensis

"Bird of Asteria, from Maastricht"

Asteriornis maastrichtensis is the oldest known modern bird with a robust cranial fossil, described in 2020 by Daniel Field and colleagues in Nature. It lived on the tropical coastal plains of Late Cretaceous Europe around 67 million years ago, some 700 thousand years before the impact that extinguished non-avian dinosaurs. The holotype NHMM 2013-008 was collected around 2000 by amateur paleontologist Maarten van Dinther at a quarry near Eben-Emael in Belgian Limburg, and donated to the Maastricht Natural History Museum. For nearly two decades the material remained in seemingly unimportant limestone blocks, until CT scans in 2018 revealed an almost complete skull hidden inside the rock. The bird was small, about 40 centimetres long and an estimated 394 grams, and its skull combines features reminiscent of both chickens and ducks, hence the global Wonderchicken nickname adopted by the press.

Cretaceous Omnivore 0.4m

AU · 95–93 Ma

Australovenator

Australovenator wintonensis

"southern hunter of Winton"

Australovenator wintonensis was a medium-sized theropod from the Cretaceous, latest Albian to Cenomanian (approximately 95 to 93 million years ago), found in the Winton Formation of central-west Queensland, Australia. About 6 meters long with an estimated weight of 310 to 500 kilograms, it was nicknamed Banjo by its discoverers in honor of Andrew Banjo Paterson, the Australian poet who wrote Waltzing Matilda. The holotype AODF 604 was excavated in 2006 by the Australian Age of Dinosaurs Museum team at locality AODL 85, within Elderslie Station, at the same site that yielded the titanosauriform sauropod Diamantinasaurus matildae, nicknamed Matilda. The association of the two skeletons in the same Cretaceous mud pocket gave the site its informal name, Matilda site, and produced a rare snapshot of a Gondwanan community at full body scale: a large herbivore alongside its potential predator. Australovenator remains the best-preserved Australian theropod, with a dentary, vertebrae, fore and hind limbs, pelvic girdle, and foot elements recovered across successive field seasons. The formal description came in 2009, in a paper published by Scott Hocknull and colleagues in PLoS ONE, which introduced the taxon together with Diamantinasaurus matildae and Wintonotitan wattsi, naming three new Winton species in a single study. In the original phylogenetic analysis, the authors placed Australovenator within Carcharodontosauria, in the family Neovenatoridae, alongside Neovenator and Fukuiraptor. This placement would be contested years later by works such as Novas and colleagues (2013), Bell and colleagues (2016), Coria and Currie (2016), and Morrison and colleagues (2025), which recover Megaraptora, the clade containing Australovenator, within Coelurosauria, close to Tyrannosauroidea. The debate is still open, and it is largely a debate about what Australovenator is: a late allosauroid or a long-armed Gondwanan tyrannosauroid. Anatomically, the animal stands out for its long forelimbs and large, recurved manual claws, which are atypical in medium and large-bodied tetanuran theropods, a group that tends to reduce its arms. White and colleagues published a sequence of papers between 2012 and 2015 describing new forearm elements, hindlimb bones, forelimb range of motion, and the dentary with its elongate, serrated teeth. This combination, long arms, enormous hands, and a slicing jaw, helped consolidate a cohesive picture of a megaraptorid: a predator that immobilizes prey with its hands and slices with its teeth, a role distinct from that of Northern Hemisphere tyrannosaurids, which relied mainly on the skull. Australovenator lived in a still partly connected Gondwana, in which Australia maintained a land link with Antarctica and, through it, dispersal routes to South America. This geography explains why Megaraptoridae has representatives both in Patagonia (Megaraptor, Aerosteon, Murusraptor, Maip) and in Australia (Australovenator, Lightning Claw). For the contemporary community, the Winton Formation yields titanosauriform sauropods such as Diamantinasaurus, Wintonotitan, and Savannasaurus, ornithopods, turtles, crocodylomorphs, and freshwater fish, depicting a warm-temperate, high-latitude floodplain of the mid-Cretaceous. In this setting Australovenator is a central piece for understanding the evolution of Gondwanan theropods and the biogeography of the group.

Cretaceous Carnivore 6m

BR · 83–72 Ma

Austroposeidon

Austroposeidon magnificus

"Magnificent southern Poseidon"

Austroposeidon magnificus is the largest dinosaur ever described from Brazil, a titanosaur roughly 25 metres long that inhabited the Late Cretaceous Bauru Basin in western São Paulo State. Its holotype MCT 1628-R was collected in 1953 by Brazilian palaeontologist Llewellyn Ivor Price on the outskirts of Presidente Prudente (SP) and sat in storage at the Museum of Earth Sciences in Rio de Janeiro for over 60 years before being formally described in 2016 by Bandeira and colleagues. The original phylogenetic analysis placed it as the sister group of Lognkosauria, while later work (Navarro et al. 2022) recovered it within Lognkosauria itself, alongside Argentinian giants such as Argentinosaurus and Patagotitan. CT scans of the cervical vertebrae revealed, for the first time in any sauropod, an internal structure alternating pneumatic camellae with dense growth rings.

Cretaceous Herbivore 25m

GB · 130–125 Ma

Baryonyx

Baryonyx walkeri

"Walker's heavy claw"

Baryonyx walkeri is one of the best-documented piscivorous dinosaurs in the history of paleontology. It lived during the Barremian of the Early Cretaceous, approximately 130 to 125 million years ago, on the fluvial floodplains of what is now Surrey, England. At roughly 9.5 meters long and an estimated 1.7 metric tons, it had a long, narrow snout similar to a gharial's, packed with finely striated conical teeth. The first-finger claw, about 31 centimeters long, gave the animal its name. The holotype NHMUK PV R9951, discovered by William Walker in 1983, was found with fish scales and juvenile iguanodontid bones in the stomach region, providing direct evidence that Baryonyx fed on both fish and terrestrial prey.

Cretaceous Piscivore 9.5m

CN · 125–124 Ma

Beipiaosaurus

Beipiaosaurus inexpectus

"Beipiao lizard, unexpected"

Beipiaosaurus inexpectus is a basal therizinosauroid from the Early Cretaceous (early Aptian, around 125 to 124 million years ago) Yixian Formation, Jianshangou Bed, near Sihetun (Beipiao, western Liaoning, China). It reached about 2.2 m in length and preserved two integumentary types: short slender filaments similar to those of Sinosauropteryx, and elongated broad filamentous feathers (EBFFs) 10 to 15 cm long, likely used for display. It was the first therizinosaur shown to bear a feather-like covering, confirming that the group, long interpreted as a late-surviving prosauropod relative, nests among maniraptoran coelurosaurs.

Cretaceous Herbivore 2.2m

CA · 112–110 Ma

Borealopelta

Borealopelta markmitchelli

"Northern shield of Mark Mitchell"

Borealopelta markmitchelli is considered the best-preserved dinosaur ever discovered. Found in 2011 at an oil sands mine in Alberta, Canada, the specimen retained skin, osteoderms in life position, and even stomach contents. Around 5.5 meters long and 1.3 metric tons, it was a heavily armored quadrupedal nodosaurid, with large parascapular spines and countershaded coloration suggesting intense predation pressure despite its armor. It was described by Caleb Brown and colleagues in 2017.

Cretaceous Herbivore 5.5m

US · 154.8–143.1 Ma

Brachiosaurus

Brachiosaurus altithorax

"Arm lizard with high thorax"

Brachiosaurus altithorax is one of the largest dinosaurs ever discovered in North America. It lived during the Late Jurassic, approximately 154 to 143 million years ago, on the alluvial plains of the Morrison Formation. It is distinguished by forelimbs longer than its hindlimbs, an extremely long neck, and a high thorax, which allowed it to reach vegetation more than 9 meters above the ground. Originally described by Elmer Riggs in 1903, it was for decades confused with its African relative Giraffatitan brancai, whose definitive taxonomic separation only occurred in 2009. With more than 26 distinct skeletal characteristics, it represents an exclusively North American genus.

Jurassic Herbivore 22m

CA · 78.5–77.5 Ma

Brachylophosaurus

Brachylophosaurus canadensis

"Short-crested lizard of Canada"

Brachylophosaurus canadensis was a medium-sized hadrosaurid that lived during the Late Cretaceous, approximately 78 to 77 million years ago, on the coastal plains that now correspond to Montana (USA) and Alberta (Canada). Its name refers to the flat paddle-shaped nasal crest, relatively short compared to other hadrosaurids with elaborate crests. It became world-famous through the specimen known as 'Leonardo', an exceptional mummy preserving skin, tendons, and even stomach contents, recognized by Guinness as the best-preserved dinosaur ever found. It possessed a sophisticated dental battery for processing tough vegetation.

Cretaceous Herbivore 9m

US · 156–146 Ma

Brontosaurus

Brontosaurus excelsus

"Noble thunder lizard"

Brontosaurus excelsus is one of the most iconic sauropods in the history of paleontology. It lived during the Late Jurassic, 156 to 146 million years ago, across the semi-arid floodplains of what is now the western United States. Up to 22 meters long and approximately 17 metric tons, it was one of the largest herbivores in its ecosystem. Its long, robust neck, far thicker than that of relatives like Diplodocus, may have served intraspecific combat roles in addition to feeding. Synonymized with Apatosaurus in 1903 by Elmer Riggs, the genus was revalidated in 2015 by Tschopp, Mateus, and Benson following the most comprehensive phylogenetic analysis ever conducted on diplodocids.

Jurassic Herbivore 22m

BR · 233–233 Ma

Buriolestes

Buriolestes schultzi

"Raider of Buriol Farm (Schultz)"

Buriolestes schultzi is one of the oldest dinosaurs in the Brazilian fossil record, from the Carnian (Late Triassic, ~233 million years ago) Santa Maria Formation in Rio Grande do Sul. Although it belongs to the sauropodomorph lineage that later gave rise to the giant herbivorous sauropods, Buriolestes was a small bipedal hunter with serrated predator teeth, a fact that rewrote the understanding of the ancestral diet of sauropodomorph dinosaurs. Specimen CAPPA/UFSM 0035, described by Müller et al. in 2018, preserves a nearly complete skeleton with a fully articulated skull, an extremely rare condition among basal sauropodomorphs. In 2021 Müller and colleagues digitally reconstructed the animal's brain (via micro-CT) and revealed a small brain with a well-developed cerebellar flocculus, consistent with an active predator. Buriolestes is a key piece for understanding the origin of dinosaurs and the transition between ancestral carnivory and derived herbivory in Sauropodomorpha.

Triassic Carnivore 1.5m

CN · 161–160 Ma

Caihong

Caihong juji

"rainbow with a big crest"

Caihong juji is a small paravian theropod from the Late Jurassic of China whose name comes from Mandarin and means rainbow with a big crest. It measures about 40 centimeters in length and weighs approximately 475 grams, placing it among the smallest known non-avian dinosaurs. The holotype PMoL-B00175, a nearly complete skeleton preserved on slab and counterslab, was found by a local farmer in 2014 in rocks of the Tiaojishan Formation, in the Qinglong Manchu Autonomous County, Hebei Province, and formally described in 2018 by an international team led by Dongyu Hu and Julia Clarke, with Xing Xu, Matthew Shawkey, and other Chinese, American, and European co-authors. Its surprising anatomy includes an elongated bony crest on the snout, formed by expanded lacrimal bones, combined with long asymmetrical pennaceous feathers on the forelimbs and along the entire tail, a morphological package without parallel in the Jurassic record. This geometry suggests Caihong already displayed elaborate ornamental surfaces long before it was capable of sustained powered flight. The most remarkable feature was revealed by scanning electron microscopy: thousands of fossilized melanosomes in feathers of the neck, chest, and base of the tail show a platelet shape, a nanostructure virtually identical to that found in living hummingbirds. In modern birds, this arrangement produces structural iridescence that shifts with the angle of incident light, so that the same individual may appear metallic green, blue, or red with subtle movements. Applying the same principle to the fossil, the authors concluded that parts of Caihong's body shimmered in metallic tones, likely in blue, green, and reddish bands, indeed recalling the rainbow that gives the genus its name. This is the first direct evidence of iridescent plumage in a non-avian dinosaur, pushing back the minimum record of this kind of coloration by roughly 40 million years, which had previously been known only in the Early Cretaceous Microraptor. The simultaneous presence of a bony crest and ornamental feathers indicates that complex visual signals, most likely linked to sexual display or species recognition, were already established at the base of Paraves. Positioned phylogenetically as an anchiornithid close to Anchiornis, Xiaotingia, and Aurornis, Caihong reinforces the idea that the origin of birds was not a linear sequence of aerodynamic innovations, but a parallel evolutionary experiment with multiple small, feathered, visually striking lineages across the Jurassic of Asia. The find also consolidates the Qinglong and Liaoning region as a global epicenter of soft-tissue paleobiology, thanks to exceptional preservation in the volcanic tuffs of the Yanliao Biota, where periodic ashfalls blanketed anoxic lakes and locked feathers, melanosomes, and even subcellular nanostructures into the sediment. For science, Caihong juji marks the moment when we stopped imagining dinosaurs in faded earth tones and began to recognize that some of them competed for mates and chased off rivals by flashing optical sparks very similar to those that today glint on the chests of hummingbirds.

Jurassic Carnivore 0.4m

US · 155–145 Ma

Camarasaurus

Camarasaurus supremus

"Supreme chambered lizard"

Camarasaurus supremus is the type species and largest member of the genus Camarasaurus, the most common sauropod of the Morrison Formation. Described by Edward Drinker Cope in 1877 from material discovered in Colorado, it was one of the first large North American sauropods to be studied systematically. It is distinguished by its tall, short skull with enormous external nostrils and particularly robust spoon-shaped teeth, adapted for a diet of tough vegetation such as tree ferns and conifers. At up to 23 meters in length and over 40 tonnes, it was the largest herbivore of its ecosystem.

Jurassic Herbivore 21m

MA · 99–94 Ma

Carcharodontosaurus

Carcharodontosaurus saharicus

"Shark-toothed lizard of the Sahara"

Carcharodontosaurus saharicus was one of the largest terrestrial predators that ever lived. It inhabited northern Africa approximately 99 to 94 million years ago during the Cenomanian stage of the Cretaceous, sharing its ecosystem with Spinosaurus. Its name means 'shark-toothed lizard of the Sahara,' a reference to the sharp serrations on its teeth, which measured up to 6.5 centimeters. At roughly 12.5 meters long with a 1.6-meter skull, it rivaled T. rex in size but had different biomechanics, specializing in slicing flesh from large sauropods rather than crushing bone. The neotype skull SGM-Din 1 was discovered by Paul Sereno in 1995 in the Kem Kem Beds of Morocco.

Cretaceous Carnivore 12.5m

AR · 72–69 Ma

Carnotaurus

Carnotaurus sastrei

"Meat-eating bull of Sastre"

Carnotaurus sastrei is one of the most distinctive predators of the Late Cretaceous of Patagonian Argentina. It stands apart from all other carnivorous dinosaurs by its pair of robust bony horns above the eyes, a feature that gave it the name 'meat-eating bull'. At approximately 8 meters long and 1.5 metric tons, it had a deep, compressed skull, extremely reduced vestigial forelimbs, and long muscular hind legs adapted for speed. It is the only theropod with extensive preserved skin impressions, revealing a mosaic of ~5 mm scales with no evidence of feathers.

Cretaceous Carnivore 8m

CN · 125–124 Ma

Caudipteryx

Caudipteryx zoui

"Tail feather (of Zou)"

Caudipteryx zoui is a small oviraptorosaurian theropod from the Early Cretaceous (basal Aptian, around 125 to 124 million years ago) Yixian Formation of western Liaoning, northeastern China. It was among the first known non-avian dinosaurs with unambiguous pennaceous feathers, preserved on the reduced wings and as a fan at the tip of the short tail. It measured about 75 to 90 cm long and weighed roughly 5 kg. The skull was short with a beak and only a few conical teeth restricted to the front of the upper jaw. Gastroliths preserved in the holotype's abdomen indicate at least partial herbivory. The wing and tail feathers were symmetrical and therefore unsuited for flight; they likely served for visual display and thermoregulation. The original description by Ji Qiang, Philip Currie, Mark Norell and Ji Shu'an in 1998 in Nature was one of the finds that consolidated the dinosaurian origin of birds.

Cretaceous Omnivore 0.9m

US · 153–148 Ma

Ceratosaurus

Ceratosaurus nasicornis

"Horned lizard with nasal horn"

Ceratosaurus nasicornis was one of the most distinctive predators of the Late Jurassic of North America. It lived approximately 153 to 148 million years ago in the Morrison Formation, sharing its ecosystem with Allosaurus and Torvosaurus. Its most striking feature is a prominent bony horn on the midline of the snout, along with a pair of ridges over the eyes. It was also the only theropod known to have osteoderms: small bony plates running along the dorsal midline. At roughly 6 meters long and 500 kg, it was an agile mid-sized predator, formally described by Othniel Charles Marsh in 1884.

Jurassic Carnivore 6m

CA · 76.5–75 Ma

Chasmosaurus

Chasmosaurus belli

"Bell's opening lizard"

Chasmosaurus belli is the prototype ceratopsid of the subfamily Chasmosaurinae, which bears its name. It lived in the late Campanian of the Cretaceous, approximately 76.5 to 75 million years ago, in Alberta, Canada, and is one of the first large ceratopsids described by science. Its most distinctive feature is the parieto-squamosal frill that is extraordinarily large relative to the skull, with two large oval openings (the parietal fenestrae) that substantially reduced the weight of the structure. The genus name Chasmosaurus refers precisely to these openings: 'khasma' in Greek means opening or chasm. This long frill, which could exceed 60% of the total skull length, is the morphological signature of the entire subfamily. The animal was originally described by Lawrence Lambe in 1902 based on fragmentary material from the Dinosaur Park Formation, but the species was only definitively established by Lambe in 1914. Subsequent studies by Brown and Schlaikjer (1940) and Dodson (1990, 1996) substantially refined the anatomy and systematics of the taxon. Chasmosaurus belli is distinguished from other species in the genus (such as C. russelli and C. irvinensis, now reclassified as Vagaceratops) mainly by the dimensions and proportions of the frill and by the relatively short facial horns. The nasal horn is low and laterally compressed, while the supraorbital horns range from short to moderate. In 2010, a juvenile specimen of Chasmosaurus belli was discovered by Brian Campione at Dinosaur Provincial Park and studied by Phillip Bell and colleagues. The importance of this fossil goes beyond the rarity of juveniles in ceratopsids: it preserved mummified skin impressions in different regions of the body, including large hexagonal scales on the flanks, smaller scales on the neck and face, and scales organized in a differentiated pattern around the eye. Pigmentation analyses preserved through scanning electron microscopy revealed melanosomes suggesting contrasting pigmentation, possibly with a counter-shading pattern (dark dorsum, pale ventrum), which would be the first direct evidence of coloration in a ceratopsid. Chasmosaurus belli's position as the founding taxon of Chasmosaurinae makes it fundamental for understanding the evolution of the entire subfamily. Modern phylogenetic analyses consistently position C. belli as one of the most basal chasmosaurines, from which more derived forms with even more elaborate frills radiate, including Pentaceratops, Anchiceratops, Torosaurus, and Triceratops. The fossil record of Chasmosaurus belli in the Dinosaur Park Formation is one of the richest of any ceratopsid, with dozens of specimens collected over more than a century of systematic excavations.

Cretaceous Herbivore 4.9m

CL · 148.7–147 Ma

Chilesaurus

Chilesaurus diegosuarezi

"Chilean lizard of Diego Suárez"

Chilesaurus diegosuarezi is a small dinosaur from the Tithonian (Late Jurassic, about 148.7 to 147 million years ago) of the Toqui Formation, Aysén Region, southern Chile. The animal became famous for combining anatomical characters from very different groups: a narrow skull and theropod-like forelimbs, an opisthopubic pelvis (pubis directed backwards) similar to that of ornithischians and birds, spatulate teeth adapted to herbivory as in prosauropods, and a tetradactyl foot with four functional ground-contacting toes. For this reason it was nicknamed the 'platypus of dinosaurs' in popular media. The holotype (SNGM-1935) is a nearly complete articulated skeleton of a juvenile about 1.6 m long; paratypes and referred specimens (SNGM-1936, 1937, 1938, 1888 and seven isolated bones) show that the adult reached about 3.2 m. It was a small to medium-sized bipedal herbivore with a moderately elongated neck and hands with only two fully developed fingers. Its phylogenetic position is debated: Novas et al. (2015) proposed a basal tetanuran theropod, Baron & Barrett (2017, 2018) recovered the taxon as the most basal ornithischian within the Ornithoscelida framework, and recent reanalyses (Baiano et al. 2022; Fonseca et al. 2023) returned to the basal tetanuran scenario. The genus is known from a single species.

Jurassic Herbivore 3.2m

MN · 75–71 Ma

Citipati

Citipati osmolskae

"Lord of the funeral pyre (Osmólska)"

Citipati osmolskae is a large oviraptorid from the Late Cretaceous (Campanian, about 75 to 71 Ma) Djadokhta Formation of the Gobi Desert, Ömnögovi Province, southern Mongolia. It reached roughly 3 metres in length and 75 to 110 kg, with a long neck, short tail, tall compressed skull, toothless jaws sheathed in rhamphotheca (horny beak) and a prominent cranial crest comparable to that of a modern cassowary. It was named in 2001 by James M. Clark, Mark A. Norell and Rinchen Barsbold on the basis of the holotype IGM 100/978, a skeleton with an exceptionally preserved skull. It became world famous for specimens such as 'Big Mama' (IGM 100/979) and 'Big Auntie' (IGM 100/1004), found in brooding posture atop clutches of elongatoolithid eggs, with forelimbs folded over the nest exactly as in modern birds. These fossils are considered some of the most iconic behavioural evidence linking non-avian dinosaurs to modern birds.

Cretaceous Omnivore 3m

US · 215–200 Ma

Coelophysis

Coelophysis bauri

"Hollow form (referring to its hollow bones)"

Coelophysis bauri is one of the oldest and best-known dinosaurs in the world. It lived in the Late Triassic, 215 to 200 million years ago, in what is now the southwestern United States. At up to 3 meters long and roughly 20 kg, it was an agile, fast predator built to chase small prey at high speed. Its hollow bones, which gave the genus its name, were an adaptation to reduce weight without sacrificing structural strength. In 1947, hundreds of skeletons were discovered at Ghost Ranch, New Mexico, forming one of the largest Triassic dinosaur deposits ever found. Coelophysis was the second dinosaur to travel to space: a skull was carried aboard the Space Shuttle Endeavour in 1998.

Triassic Carnivore 3m

DE · 150–145 Ma

Compsognathus

Compsognathus longipes

"Elegant jaw"

Compsognathus longipes was for more than a century the smallest known non-avian dinosaur, an agile and delicate theropod of the Late Jurassic (Tithonian, ~150-145 Ma) that inhabited the margins of shallow archipelagos in what is now central Europe. The holotype BSP AS I 563, preserved in the Solnhofen lithographic limestones of Bavaria, revealed an animal approximately 89 cm long with very short forelimbs, a long flexible neck, and a gracile skull with small pointed teeth. A lizard preserved inside the holotype's torso provided direct evidence of feeding behavior: Compsognathus actively hunted small prey, swallowing them whole or in large pieces. The second known specimen, MNHN CNJ 79, recovered at Canjuers in the French Provence, is substantially larger — about 1.25 m long — which generated decades of debate about whether it represented adults of C. longipes or a distinct species (Compsognathus corallestris, proposed by Bidar et al. in 1972), a question now resolved in favor of ontogenetic variation within a single species.

Jurassic Carnivore 1.2m

ES · 130–125 Ma

Concavenator

Concavenator corcovatus

"Hunchbacked hunter from Cuenca"

Concavenator corcovatus is a carcharodontosaurid from the Early Cretaceous of Spain, described in 2010 by Ortega, Escaso, and Sanz from a nearly complete skeleton found at the Las Hoyas site in Cuenca. Its most striking feature is a dorsal hump formed by the extreme elongation of the last two dorsal vertebrae, creating a short crest or sail above the hip region. The specimen also shows small bumps on the ulna interpreted as possible quill knob attachment points, making it the most basal non-avian theropod known with this evidence. Measuring approximately 6 meters long and weighing around 400 kg, it was the apex predator of its lacustrine ecosystem in Cretaceous Iberia.

Cretaceous Carnivore 6m

CN · 125–120 Ma

Confuciusornis

Confuciusornis sanctus

"Sacred Confucius bird"

Confuciusornis sanctus is the most abundant Mesozoic bird in the world fossil record: hundreds of specimens, many exquisitely preserved with feathers, have been extracted from the Yixian and Jiufotang formations of Liaoning, northeastern China. This unparalleled abundance made Confuciusornis the most studied extinct bird taxon in the world, capable of providing data on morphology, ontogeny, coloration, paleoecology, and social behavior simply not accessible for rarer birds. It lived during the Barremian to Aptian of the Early Cretaceous, approximately 125 to 120 million years ago, and represents one of the most important morphological innovations in bird history: it was the first toothless Mesozoic bird with a true horny beak and a fused tail bone forming a pygostyle. Confuciusornis morphology combines primitive and derived features remarkably. On one hand, the forelimbs retain three functional clawed fingers, and the skull retains some primitive skeletal features relative to modern birds. On the other, the complete absence of teeth, the horny beak, and the pygostyle are innovations we know mainly from modern birds, making Confuciusornis much more externally similar to a modern bird than Archaeopteryx or other contemporaries. The tail, short due to the pygostyle, accommodated in long-tailed forms a pair of very long, narrow ribbon-like rectrices whose function was probably social display. The presence or absence of these tail feathers in different specimens has historically been interpreted as sexual dimorphism, but recent analyses with ontogenetically comparable specimens question this simple interpretation. Confuciusornis flight is considered truly active, not just gliding: the sternum morphology, with well-developed keel for flight muscle insertion, and wing proportions suggest sustained powered flight capability. However, biomechanical analyses indicate the flight pattern would differ from modern birds: the shoulder joint, clavicle position, and relative proportions of humerus and ulna suggest an aerodynamically less efficient flight style compared to neornithean birds. Bone histology studies show Confuciusornis had slower growth rates than modern birds of comparable size, reaching skeletal maturity in one or two years, closer to reptiles than to modern birds.

Cretaceous Omnivore 0.5m

CA · 77–75 Ma

Corythosaurus

Corythosaurus casuarius

"Cassowary-helmeted lizard"

Corythosaurus casuarius was one of the most striking hadrosaurids of the Late Cretaceous, living 77 to 75 million years ago on the coastal plains of North America. Its name honors the cassowary, a modern bird with a prominent bony helmet, a direct reference to the large hollow helmet-shaped crest that dominated the top of the skull. That crest was no empty ornament: it contained S-shaped nasal passages that functioned as a resonating chamber, amplifying low-frequency vocalizations used in social communication. Measuring up to 9 meters and weighing around 3.8 metric tons, it is one of the best-documented dinosaurs from the Dinosaur Park Formation.

Cretaceous Herbivore 9m

AQ · 194–182 Ma

Cryolophosaurus

Cryolophosaurus ellioti

"Elliott's frozen-crested lizard"

Cryolophosaurus ellioti was the largest predator of the Early Jurassic in Antarctica and the first large-bodied theropod described from the continent. At roughly 6.5 meters long and an estimated 465 kg, it was distinguished by a unique transverse crest on the skull, formed by the lacrimal bones and oriented perpendicular to the snout axis, unlike any other known dinosaur. This feature earned it the informal nickname 'Elvisaurus.' Discovered in 1991 by paleontologist William Hammer in the Transantarctic Mountains, the holotype (FMNH PR1821) was extracted from over 2,300 kg of rock and represents a subadult. Its phylogenetic position is debated, placing it as a basal neotheropod close to Averostra.

Jurassic Carnivore 6.5m

US · 247–244 Ma

Cymbospondylus

Cymbospondylus youngorum

"Young's cupped vertebrae (from Greek: kymbe, cup; spondylos, vertebra; youngorum honors Tom and Bonda Young)"

Cymbospondylus youngorum is a giant ichthyosaur from the Middle Triassic, described in 2021 by Sander and colleagues in Science. At roughly 17.65 meters long and an estimated 44.7 metric tons, it was the largest vertebrate of its time, on land or sea, and is considered the first true giant of the Mesozoic oceans. Its nearly 2-meter-long skull is elongated and filled with conical teeth bearing longitudinal ridges, suggesting a generalist diet of squid, fish, and possibly other marine reptiles. It was found in the Fossil Hill Member of the Favret Formation in the Augusta Mountains of Nevada, around 246 million years ago. The most striking aspect is evolutionary: the species appeared only about 3 million years after the first ichthyosaurs, showing that the lineage reached gigantism far faster than modern whales, which took tens of millions of years to achieve comparable size.

Triassic Piscivore 17m

US · 67–66 Ma

Dakotaraptor

Dakotaraptor steini

"Dakota raider, of Stein"

Dakotaraptor steini is a large dromaeosaurid from the Late Cretaceous (late Maastrichtian, about 66 to 67 million years ago) of the Hell Creek Formation, Harding County, South Dakota. Described by Robert DePalma, David Burnham, Larry Martin, Peter Larson and Robert Bakker in 2015, it reached 4.35 to 6 metres in length with an estimated body mass of 220 to 350 kilograms, making it the largest known Maastrichtian dromaeosaurid of North America and one of the largest of the family, alongside Utahraptor and Achillobator. The holotype PBMNH.P.10.113.T consists of a partial skeleton of a subadult to adult individual lacking a skull, discovered by Robert DePalma in 2005 in a Hell Creek fluvial channel no more than 20 metres below the Cretaceous-Palaeogene boundary. The ulna preserves about 15 ulnar papillae (quill knobs) of 8 to 10 millimetres in diameter, indicating attachment of large pennaceous feathers, and the second-toe 'sickle claws' typical of dromaeosaurids reach 24 centimetres along the outer curve. The tibia, 678 millimetres long, is the longest known in any dromaeosaurid, suggesting surprisingly gracile limb proportions for an animal of this size. In 2016, Arbour and colleagues demonstrated that the furculae originally described as part of the holotype were in fact entoplastra (parts of the shell) of the trionychid turtle Axestemys splendida, and DePalma et al. (2016) issued a corrigendum excluding those elements. The validity of the taxon remains debated: Cau (2023 and 2024) argued, in blog and phylogenetic analyses, that the remaining material may be a chimera combining ornithomimosaur, oviraptorosaur and therizinosaur elements, but this hypothesis has not yet been published in a peer-reviewed article.

Cretaceous Carnivore 5m

CA · 77–74 Ma

Daspletosaurus

Daspletosaurus torosus

"Frightful and muscular lizard"

Daspletosaurus torosus was one of the largest terrestrial predators of the Campanian in North America, approximately 9 meters long and weighing 2.5 metric tons. It inhabited what is now Alberta, Canada, between 77 and 74 million years ago. A member of the tribe Daspletosaurini within the family Tyrannosauridae, it was a direct ancestor in the lineage leading to Tyrannosaurus rex. It possessed the largest teeth among tyrannosaurids of its time, proportionally larger than those of T. rex itself, and was the first tyrannosaurid for which stomach contents were identified, revealing it preyed on hadrosaurs. Healed bite marks on skulls indicate intraspecific combat.

Cretaceous Carnivore 9m

MN · 72–66 Ma

Deinocheirus

Deinocheirus mirificus

"Peculiar horrible hand"

Deinocheirus mirificus was one of paleontology's greatest mysteries for nearly 50 years. Discovered in 1965 in Mongolia only through its gigantic arms — 2.4 meters with curved claws — it remained bodyless until 2014, when two nearly complete skeletons were described by Lee et al. in Nature. The result astonished: the largest known ornithomimosaur measured about 11 meters, weighed 6.4 tons, possessed a dorsal sail formed by tall neural spines, a broad hadrosaur-like bill, and an omnivorous diet including fish and aquatic plants.

Cretaceous Omnivore 11m

US · 119–108 Ma

Deinonychus

Deinonychus antirrhopus

"Terrible counterbalanced claw"

Deinonychus antirrhopus was one of the most sophisticated predators of the Early Cretaceous of North America. At approximately 3.4 meters long and 85 kg, it was distinguished by an enormous sickle-shaped claw on the second toe, measuring over 12 centimeters. Described by John Ostrom in 1969, Deinonychus revolutionized paleontology by demonstrating that dinosaurs could be agile, active animals, possibly endothermic. This discovery initiated the so-called 'Dinosaur Renaissance' and directly influenced the creation of Jurassic Park. The animal was also pivotal in establishing the hypothesis that birds are descended from theropod dinosaurs.

Cretaceous Carnivore 3.4m

US · 196–183 Ma

Dilophosaurus

Dilophosaurus wetherilli

"Two-crested lizard (honoring John Wetherill)"

Dilophosaurus wetherilli was the largest land predator in North America during the Early Jurassic, reaching about 7 meters in length and 400 kg. Its most distinctive feature was a pair of parallel crests running along the top of its skull, thin and delicate structures that likely served for visual display and species recognition. It lived approximately 196 to 183 million years ago in the Kayenta Formation of present-day Arizona, USA. The comprehensive anatomical revision by Marsh and Rowe (2020) confirmed the animal had robust jaws strong enough to puncture bone, overturning the notion it was a weak predator. There was no frill and no venom: these elements are inventions of the film Jurassic Park (1993).

Jurassic Carnivore 7m

US · 154–152 Ma

Diplodocus

Diplodocus carnegii

"Carnegie's double beam"

Diplodocus carnegii is one of the largest animals ever to walk the Earth, reaching about 26 meters in length. It lived during the Late Jurassic, 154 to 152 million years ago, on the semi-arid plains of the Morrison Formation in the western United States. Its long neck and slender, whip-like tail served as counterweights. Peg-like teeth set only at the front of the jaw were specialized for raking low vegetation. The species was named in honor of industrialist Andrew Carnegie, who funded the excavation of the holotype specimen CM 84 in 1899. Plaster casts of its skeleton were distributed to museums worldwide, making Diplodocus carnegii the most-viewed dinosaur on the planet.

Jurassic Herbivore 26m

US · 66–66 Ma

Dracorex

Dracorex hogwartsia

"Dragon king of Hogwarts"

Dracorex hogwartsia is one of the dinosaurs with the most peculiar story in paleontology: it was named by children, in honor of a fictional school of witchcraft, and its status as a valid species is one of the most contentious taxonomic debates of the Late Cretaceous. Described in 2006 by Robert Bakker and collaborators based on a nearly complete skull discovered in the Hell Creek of South Dakota by a group of amateur fossil hunters, the animal presented a cranial morphology radically different from other known pachycephalosaurids: the skull was long, low, and flat, without any trace of a bony dome, but decorated with an impressive series of horns and nodules along the frontoparietal and temporal region. The visual result is, in fact, remarkably similar to medieval descriptions of dragons, which inspired the specimen's donors, children from the Children's Museum of Indianapolis, to propose the name to the paleontologist. The main scientific controversy surrounding Dracorex was raised in 2009, when Jack Horner and Mark Goodwin published a detailed histological analysis of the skull. Upon examining the microstructure of the frontoparietal bone, they found immature bone tissue (fibrolamellar, with abundant vasculature and without complete remodeling) characteristic of young individuals, not adults with completed bone growth. Horner and Goodwin's hypothesis is that Dracorex hogwartsia is not a distinct species, but rather a juvenile of Pachycephalosaurus wyomingensis: the flat skull with horns would be the initial state, and the dome would form progressively during growth, similar to the development of horns in sheep. This interpretation would also unify Stygimoloch spinifer as a teenager of Pachycephalosaurus, consolidating three names into a single taxon. The synonymy proposal, while widely accepted by many specialists, remains formally controversial. Other researchers, such as Robert Sullivan (2006) and David Evans and collaborators (2013), argue that the morphological differences between the skulls are too pronounced to be explained by ontogeny alone, and that Dracorex may represent a distinct lineage of flat-skulled pachycephalosaurids that lived in sympatry with Pachycephalosaurus. The question is complicated by the rarity of specimens: only one Dracorex skull is known with certainty, making it impossible to establish complete ontogenetic series. Regardless of taxonomic resolution, the Dracorex skull is one of the most extraordinary known among ornithischian dinosaurs. The tubercles, spines, and nodules covering the cranial surface have no parallel in any other pachycephalosaurid, and their function continues to be debated: they may have served for intraspecific recognition, surface thermoregulation, sexual display, or passive defense. The preservation of the specimen, with unusually well-conserved cranial surface details, has made Dracorex one of the most studied and artistically represented dinosaurs of the last twenty years.

Cretaceous Herbivore 2.4m

AR · 77–70 Ma

Dreadnoughtus

Dreadnoughtus schrani

"Fears nothing (honoring Adam Schran, donor who funded the excavations)"

Dreadnoughtus schrani was one of the largest land animals ever to exist. Discovered in Patagonian Argentina in 2005 by Kenneth Lacovara and formally described in 2014, this giant titanosaur lived between 77 and 70 million years ago, during the Late Cretaceous. At roughly 26 meters long and an estimated mass of 65 tonnes, it was the size of a dozen African elephants. The holotype is one of the most complete giant titanosaur skeletons ever found, with approximately 70% of the bones preserved, making it exceptional for an animal of this size. The genus name references the dreadnought battleships of the early 20th century, warships so powerful they 'feared nothing.' The species honors Adam Schran, the philanthropist who funded the field expeditions.

Cretaceous Herbivore 26m

CA · 76–73 Ma

Edmontonia

Edmontonia rugosidens

"Edmonton lizard with wrinkled teeth"

Edmontonia rugosidens was a large-bodied nodosaurid that lived in the Late Cretaceous, during the Campanian, approximately 76 to 73 million years ago, across the coastal plains of western North America that formed the island continent of Laramidia. About 6.5 meters long and with an estimated mass of three metric tons, it was a massive quadrupedal herbivore covered by impressive dermal armor composed of rows of osteoderms along the back, flanks, and base of the tail. The taxonomic history of the species begins in 1930, when Charles W. Gilmore described material recovered by George Fryer Sternberg in 1928 from the Two Medicine Formation of Montana. Gilmore coined the epithet rugosidens in reference to the wrinkled surface of the small leaf-shaped teeth of the animal, assigning the species to the genus Palaeoscincus, then used as a dumping ground for isolated ankylosaur teeth. A decade later, in 1940, Loris S. Russell reexamined the material and erected the new genus Edmontonia, named after the Edmonton Formation, a stratigraphic unit that also preserved related specimens in southern Alberta. Edmontonia belongs to the family Nodosauridae, the sister group of Ankylosauridae within Ankylosauria. The most striking anatomical difference between the two families lies in the tail. Ankylosaurids such as Ankylosaurus and Euoplocephalus evolved the famous tail club formed by fused osteoderms at the tip of the tail, used as an impact weapon. Edmontonia and other nodosaurids never evolved this structure. Instead, both passive and active defense were concentrated in its body armor and, above all, in a set of enormous spikes projecting laterally from the shoulders, a structure particularly developed in Edmontonia and interpreted as a possible weapon in intraspecific contests between males, in addition to defense against predators such as the tyrannosaurids Gorgosaurus and Daspletosaurus. The ecological context of Edmontonia rugosidens is the Dinosaur Park Formation ecosystem of Alberta, one of the richest dinosaur-bearing sedimentary units of the Cretaceous. The environment consisted of moist coastal plains under the influence of the Western Interior Seaway, with meandering rivers, wetlands, and dense vegetation of conifers, cycads, and early flowering plants. The contemporary fauna included ceratopsids such as Centrosaurus and Styracosaurus, hadrosaurids such as Corythosaurus and Lambeosaurus, and the predators Gorgosaurus and Daspletosaurus. The fossil record of the species is remarkably rich compared with that of other ankylosaurs. Several specimens preserve the dermal armor near its original position, allowing detailed reconstructions of the arrangement of cervical, dorsal, and lateral osteoderms. The holotype USNM 11868, the AMNH 5381 skull and partial skeleton, and the complete AMNH 5665 material are the central anatomical references. The historical documentation by William Diller Matthew in 1922 at the American Museum of Natural History produced some of the first systematic reconstructions of the armor of a nodosaurid, an iconography that shaped how Edmontonia was depicted in museums and popular literature for decades.

Cretaceous Herbivore 6.5m

US · 73–66 Ma

Edmontosaurus

Edmontosaurus annectens

"Edmonton lizard (connected)"

Edmontosaurus annectens was one of the largest and most abundant herbivores of the late North American Cretaceous. Up to 12 meters long and around 5.6 metric tons, it roamed in herds across the floodplains of the Hell Creek Formation 73 to 66 million years ago. Its broad, flat snout, typical of hadrosaurs, housed a sophisticated dental battery of hundreds of replacement teeth adapted for grinding fibrous vegetation. It is famous for the 'mummy' AMNH 5060, a specimen with preserved skin revealing polygonal scales and soft tissue, and for evidence of predation by Tyrannosaurus rex.

Cretaceous Herbivore 12m

AR · 231–228 Ma

Eoraptor

Eoraptor lunensis

"Dawn thief (of the moon)"

Eoraptor lunensis is one of the oldest dinosaurs known to science. It lived approximately 231 million years ago during the Late Triassic (Carnian stage) in what is now San Juan Province, Argentina. At only 1.2 meters long and roughly 10 kg, it was a small, agile biped with heterodont dentition: serrated recurved teeth at the front of the jaw and leaf-shaped teeth toward the back, suggesting an omnivorous diet. Described by Sereno et al. in 1993 from a nearly complete skeleton, Eoraptor offers a unique window into dinosaur origins and the Triassic ecosystem of Gondwana.

Triassic Omnivore 1.2m

CA · 76.5–66 Ma

Euoplocephalus

Euoplocephalus tutus

"Well-armored and protected head"

Euoplocephalus tutus is the best-documented ankylosaur in the history of paleontology: more than 40 specimens have been collected since the original description in 1902, including several complete skulls, dermal armor in association, and at least one complete tail with preserved bony club. It lived in the late Campanian of the Cretaceous, approximately 76.5 to 66 million years ago, in North America, with records in Alberta (Canada) and possibly Montana (USA). It is the only ankylosaur for which sufficient material exists to characterize individual and ontogenetic morphological variation within the species with any degree of confidence. The animal had extensive dermal armor composed of osteoderms of multiple types: large flat plates on the back, cones or spines along the flanks, smaller scales filling the spaces between larger ones, and a hardened skin covering over the skull. Notably, Euoplocephalus had ossified eyelids, a unique adaptation protecting the eyes from predatory attacks. The tail terminated in a bony club (fused tail osteoderm, the 'golf club') whose size and robustness were analyzed by Arbour (2009) as sufficient to generate impact forces capable of fracturing bones of large predators like Tyrannosaurus and Gorgosaurus. In terms of systematics, the history of Euoplocephalus is complex. Many ankylosaur specimens from Alberta were originally referred to E. tutus based on the assumption that there would be only one ankylosaur species per formation. More recent research by Arbour and Currie (2013, 2015) reassessed this material and concluded that several specimens previously referred to E. tutus belong to distinct genera and species (such as Scolosaurus cutleri, Anodontosaurus lambei, and Dyoplosaurus acutosquameus). After this revision, the number of specimens truly referable to E. tutus decreased, but the taxon remains the best-characterized ankylosaur of the Campanian of North America. Arbour's (2009) biomechanical analysis of the tail club is one of the most cited results in ankylosaur paleobiology: using structural mechanics models and comparisons with modern hammers, Arbour demonstrated that the E. tutus club could generate impact forces of 2-6 kN, sufficient to fracture the ribs or tibiae of Tyrannosaurus or Gorgosaurus. Tail musculature, inferred from well-developed transverse processes, was capable of moving the club in high-speed lateral arcs. This analysis changed the scientific understanding of the tail club from a possible display ornament to an active and effective defensive weapon.

Cretaceous Herbivore 6m

DE · 154–151 Ma

Europasaurus

Europasaurus holgeri

"Holger's European lizard"

Europasaurus holgeri is a basal macronarian sauropod from the Late Jurassic (middle Kimmeridgian, about 154 to 151 million years ago) of the Langenberg Quarry in Oker, northern Germany. Described by Sander, Mateus, Laven and Knötschke in 2006 in Nature, it became famous as the first unequivocally documented case of insular dwarfism in dinosaurs. Fully grown adults measured only 5.7 to 6.2 metres in length and weighed between 750 and 2,100 kg, comparable to a large horse, while close relatives such as Brachiosaurus and Camarasaurus exceeded 20 metres. Bone histology of femora and tibiae, published in the original description, demonstrated that this small size was not a juvenile effect but corresponded to mature individuals with reduced growth rate, consistent with populations isolated on an island of the Lower Saxony Archipelago during the Kimmeridgian marine transgression. More than 450 bones have been collected at the site, representing at least 14 individuals in different ontogenetic stages, including partial skulls and complete dentitions, which makes Europasaurus one of the most abundant and three-dimensionally preserved sauropods from the European Jurassic.

Jurassic Herbivore 6.2m

AR · 90–86 Ma

Futalognkosaurus

Futalognkosaurus dukei

"Giant chief lizard (from the Mapuche language)"

Futalognkosaurus dukei is one of the most complete titanosaurs ever discovered, with approximately 70% of the skeleton preserved across three specimens. Found in 2000 on the shores of Lake Barreales in Neuquén, Argentine Patagonia, it was formally described in 2007 by Calvo, Porfiri, González-Riga, and Kellner. With length estimates ranging from 24 to 30 meters, it belonged to the clade Lognkosauria, a group of giant titanosaurs that also includes Mendozasaurus and possibly Argentinosaurus. Its cervical vertebrae with extraordinarily tall neural spines, exceeding one meter, distinguish it from other sauropods and suggest unique adaptations for neck muscle support.

Cretaceous Herbivore 26m

MN · 72–66 Ma

Gallimimus

Gallimimus bullatus

"Chicken mimic with bulla"

Gallimimus bullatus is the largest known ornithomimosaur, living approximately 70 million years ago in what is now Mongolia. At up to 6 meters long and around 440 kg, it was a swift biped capable of reaching between 42 and 56 km/h. Toothless, it had a rounded keratinous beak and long neck, adapted to an apparently herbivorous diet. Discovered during Polish-Mongolian expeditions in the 1960s, it became the most complete and well-documented ornithomimosaur of the Cretaceous, and gained worldwide fame by appearing in the herd stampede scene of the 1993 film Jurassic Park.

Cretaceous Herbivore 6m

US · 152–148 Ma

Gargoyleosaurus

Gargoyleosaurus parkpinorum

"gargoyle lizard of the Parkpins (fossil-donating family)"

Gargoyleosaurus parkpinorum was one of the oldest and most primitive ankylosaurs ever described by science. It lived near the end of the Late Jurassic, approximately 152 to 148 million years ago, in interior Laurasia, in a region that today corresponds to the state of Wyoming, United States. Its partial skeleton, including an almost complete skull, was found in 1995 at Bone Cabin Quarry West, in Albany County, within rocks of the Morrison Formation. The fossil was prepared by the Western Paleontological Laboratories team and formally described in 1998 by Kenneth Carpenter, Clifford Miles and Karen Cloward, in the volume The Armored Dinosaurs, published by Indiana University Press. Under the plural rule of the International Code of Zoological Nomenclature (ICZN), the original specific epithet, parkpini, was emended to parkpinorum, honoring siblings Tyler and Jolene Parkpin, whose family donated the specimen to the Denver Museum of Nature and Science. About 3.5 meters long and roughly 600 kilograms in weight, it was a quadrupedal herbivore with a low-slung body, a back covered by conical osteoderms, and elongated lateral spines. It preserved ancestral traits that set it apart from later ankylosaurs, including an open antorbital fenestra, simple dentition with seven conical teeth per premaxilla, and dermal armor less elaborate than that of Cretaceous forms such as Ankylosaurus or Euoplocephalus. The rough skull shows pronounced deltoid bosses and moderate dermal ornamentation, and the broad premaxilla appears without the full fusion of cranial plates, an ancestral state that would only be abandoned in the Late Cretaceous. The shoulder region bore the insertion of two pairs of long conical spines, whose arrangement has inspired several paleoartistic reconstructions of the genus. Its phylogenetic position is debated: different analyses recover it either as a basal ankylosaur close to Mymoorapelta, or as a member of Nodosauridae, always outside the crown group, and the Wiersma and Irmis (2018) cladogram has become the modern reference for this discussion. It shared its world with gigantic sauropods such as Apatosaurus, Diplodocus, Camarasaurus and Brachiosaurus, with stegosaurs like Stegosaurus, with ornithopods like Camptosaurus and Dryosaurus, and with predatory theropods such as Allosaurus and Ceratosaurus, composing one of the best-documented dinosaur faunas on the planet. In that setting, Gargoyleosaurus occupied the niche of a low, well-protected herbivore, grazing on ferns, horsetails and ground-level foliage while relying on its armor to deter attacks. The name Gargoyleosaurus, gargoyle lizard, refers to the rough and angular appearance of the skull, which resembles the stone carvings on medieval European cathedrals.

Jurassic Herbivore 3.5m

AR · 99–95 Ma

Giganotosaurus

Giganotosaurus carolinii

"Giant southern lizard"

Giganotosaurus carolinii was one of the largest terrestrial predators ever known, with an estimated length of up to 13 meters and mass around 7 tonnes. Discovered in 1993 by Rubén Carolini in the Candeleros Formation of Neuquén, Argentina, and described by Coria and Salgado in 1995, it belongs to the family Carcharodontosauridae. Its skull measured 1.56 m, larger than that of T. rex, with serrated teeth resembling shark teeth. It lived during the Cenomanian (~99–95 Ma), sharing its ecosystem with giant titanosaurs like Andesaurus and Argentinosaurus. Isotope analysis of bones suggests an intermediate metabolism between reptiles and mammals, and computer simulations indicate a maximum running speed of approximately 14 m/s.

Cretaceous Carnivore 13m

TZ · 154–150 Ma

Giraffatitan

Giraffatitan brancai

"Giraffe titan"

Giraffatitan brancai was a giant brachiosaurid sauropod that lived during the Kimmeridgian to Tithonian of the Late Jurassic, approximately 154 to 150 million years ago, in what is now Tanzania. At 26 meters in length and estimated body mass of 35,000 to 40,000 kg, it was one of the largest land animals of its time. Giraffatitan's morphology is characterized by forelimbs significantly longer than the hindlimbs, resulting in a forward-sloping back and an extremely long and high neck that allowed the animal to reach the vegetation of tree canopies in the East African Jurassic forest. Unlike many sauropods that held the neck horizontally, Giraffatitan's skeletal proportions indicate the neck was raised at a steep angle, giving the animal a vertical silhouette reminiscent of a giraffe, hence the name. The separation of Giraffatitan from Brachiosaurus as a distinct genus was proposed by Paul (1988) and confirmed by Taylor (2009) after detailed cladistic analysis. Key anatomical differences include skull configuration, taller and with a more prominent nasofrontal crest in Giraffatitan, and cervical vertebrae proportions, more elongate and with lower robustness index in Giraffatitan than in Brachiosaurus altithorax from North America. The validity of Giraffatitan as a separate genus is currently consensus in the paleontological community, though some authors have suggested both could belong to the same genus with subgenus status. Fossil material of Giraffatitan brancai is exceptionally rich for a giant sauropod: German expeditions to Tanzania between 1909 and 1913, led by Werner Janensch, recovered remains of dozens of individuals, including materials from at least five partially articulated individuals. The composite specimen HMN SII, mounted at the Museum für Naturkunde in Berlin, is the tallest mounted dinosaur skeleton in the world, at 13.27 meters. The logistical operation of the Tendaguru expeditions was one of the largest paleontological endeavors in history: more than 250 African workers transported hundreds of tons of fossilized material over 60 kilometers from the East African coast under extremely adverse conditions.

Jurassic Herbivore 26m

BR · 233–233 Ma

Gnathovorax

Gnathovorax cabreirai

"Voracious jaws (of Cabreira)"

Gnathovorax cabreirai is one of the earliest bipedal predators in the fossil record, living around 233 million years ago in what is now central Rio Grande do Sul. Roughly 3 metres long, it was a medium-sized herrerasaurid that dominated its ecosystem alongside rhynchosaurs, cynodonts and the first sauropodomorphs. Holotype CAPPA/UFSM 0009, discovered in 2014 by Sérgio Cabreira at the Marchezan site in São João do Polêsine, preserves an articulated skeleton with a near-complete skull and is among the best-preserved Herrerasauridae specimens ever found. The name literally means 'voracious jaws', a direct reference to its robust skull and serrated teeth adapted for active predation. Given the completeness of the material, Gnathovorax has been decisive in reassessing the phylogenetic position of herrerasaurids at the start of the dinosaur radiation.

Triassic Carnivore 3m

CA · 77–75 Ma

Gorgosaurus

Gorgosaurus libratus

"Balanced fierce lizard"

Gorgosaurus libratus was one of the apex predators of the North American Campanian, living 77 to 75 million years ago in what is now Alberta, Canada, and Montana, USA. Measuring roughly 8 to 9 meters in length and weighing approximately 2,400 kg, it was smaller than Tyrannosaurus rex but shared its bipedal stance, reduced forelimbs, and powerful jaws. It is considered the best-represented tyrannosaurid in the fossil record, with dozens of specimens spanning a full ontogenetic series from juvenile to adult. Bone histology studies have revealed detailed growth patterns, and a juvenile with preserved stomach contents demonstrated that young individuals hunted small prey while adults targeted hadrosaurs and ceratopsians.

Cretaceous Carnivore 9m

AR · 231–229 Ma

Herrerasaurus

Herrerasaurus ischigualastensis

"Herrera's lizard from Ischigualasto"

Herrerasaurus ischigualastensis is one of the most primitive known dinosaurs, living approximately 231 to 229 million years ago in South America. Up to 6 meters long and around 350 kg, it was the apex predator of the Ischigualasto Formation ecosystem in Argentina. An agile biped, it had forelimbs specialized for grasping prey and a unique intramandibular joint in its lower jaw that enhanced prey capture and retention. Its phylogenetic position remains debated: classified variously as a basal theropod or as a pre-eusaurischian saurischian. The complete skull, discovered by Sereno and Novas in 1988, revolutionized understanding of the earliest dinosaurs.

Triassic Carnivore 6m

US · 84–78 Ma

Western Bird

Hesperornis regalis

"Royal western bird"

Hesperornis regalis was a giant aquatic bird of the Late Cretaceous that lived around 84 to 78 million years ago in the Western Interior Seaway, the vast epicontinental sea that split North America in two. It reached about 1.8 meters in length, with an estimated weight near 9 kilograms (estimate based on length and diving morphology). It did not fly: the wings were vestigial, reduced to a short humerus without functional radius or ulna. To compensate, it had huge lobed feet, a specialized tarsometatarsal joint for lateral strokes, and dense bones. Unlike modern birds, it still retained recurved teeth set in grooves, a legacy of non-avian theropod ancestors. Functionally it was the Cretaceous equivalent of a penguin or imperial diver, but with toothed jaws. The original description came from Othniel Charles Marsh in 1872, during the heat of the Bone Wars, from Niobrara Chalk material of Kansas.

Cretaceous Piscivore 1.8m

ZA · 201–196 Ma

Heterodontosaurus

Heterodontosaurus tucki

"Tuck's different-toothed lizard"

Heterodontosaurus tucki is one of the most primitive ornithischians known and certainly the most anatomically surprising of its time. It lived in the Early Jurassic, approximately 201 to 196 million years ago, on the semi-arid plains of what is now South Africa, in the Upper Elliot Formation. At only 1.2 meters in length and under 2 kg, it was an agile biped with long hind limbs and relatively robust forelimbs, likely using its hands to manipulate vegetation or small prey. Its skeleton is extraordinarily well preserved, with the skull SAM-PK-K1332 being one of the most complete among primitive Triassic-Jurassic dinosaurs. The defining feature of the genus, reflected in its name, is its radically heterogeneous dentition: unlike the vast majority of herbivorous dinosaurs, Heterodontosaurus possessed three distinct types of teeth. At the front of the upper jaw were small incisor-like teeth for cropping vegetation, followed by large canine-like tusks at the corners of the maxilla and dentary, and taller, laterally compressed cheek teeth with crushing edges for processing plant food. This combination of three distinct dental morphologies in a single animal is unique among Dinosauria and generated decades of debate about function and diet. The question of the tusks is the most controversial aspect of Heterodontosaurus biology. Crompton and Charig, when describing the species in 1962, suggested omnivorous use. Later studies, especially those of Santa Luca (1980) and Sereno (2012), raised the hypothesis of sexual dimorphism: the tusks would be exclusive to males and would function in display or intraspecific combat, analogous to modern deer and suids. Norman et al. (2011), upon reexamining the material, concluded that the canine teeth were not related to carnivory but rather to social behavior. Porro et al. (2011) performed biomechanical analysis of the jaw and confirmed that its structure was highly adapted to processing hard plant material. Heterodontosaurus is also notable for its phylogeny. For decades it was placed at the base of ornithopods, but modern analyses position it at the base of Ornithischia or as a member of a lineage sister to Genasauria. This makes it a valuable window into the early stages of ornithischian dinosaur evolution, before the great diversification that produced hadrosaurs, ceratopsians, ankylosaurs, and stegosaurs. Additionally, possible evidence of keratin on the anterior teeth suggests a partial horny beak, as in many modern birds and turtles.

Jurassic Omnivore 1.2m

CN · 169–164 Ma

Huayangosaurus

Huayangosaurus taibaii

"Huayang lizard (poet Li Bai)"

Huayangosaurus taibaii was a small Middle Jurassic stegosaur from southern China, collected at the Dashanpu Quarry near Zigong, Sichuan Province. At roughly 4.5 meters long and about 300 kg, it was much smaller than the famous North American Stegosaurus, yet it carries enormous scientific weight: it is the oldest well-known stegosaur recovered from abundant remains, serving as a key reference for understanding the origin and early diversification of the group. The genus name refers to Huayang, an ancient place name for Sichuan Province, while the specific epithet honors the Tang dynasty poet Li Taibai, also known as Li Bai. Described in 1982 by Dong Zhiming, Tang Zilu, and Zhou Shiwu, the holotype IVPP V6728 includes a relatively complete skull, vertebrae, ribs, caudals, and osteoderms, belonging to one of twelve individuals recovered from the site. This material made Huayangosaurus the best-documented Middle Jurassic stegosaur and the anatomical baseline for comparisons with derived forms such as Stegosaurus and Kentrosaurus. Several traits preserved in Huayangosaurus are regarded as primitive for Stegosauria: it still has teeth in the premaxilla (lost in later stegosaurs), retains open antorbital and mandibular fenestrae (both closed in derived forms), and has a shorter, broader skull. Its dorsal armor consisted of 17 pairs of plates and spikes arranged in two rows, intermediate in shape between the flat plates of Stegosaurus and the long spines of Kentrosaurus, plus a thagomizer with two terminal spike pairs and a distinctive parascapular spine on each shoulder. The forelimbs were proportionally longer relative to the hindlimbs than in Stegosaurus, giving it a less extreme body profile. The animal lived on the warm, humid floodplains of the Lower Shaximiao Formation alongside the sauropods Shunosaurus and Omeisaurus, the small ornithopod Xiaosaurus, and the carnivorous theropod Gasosaurus. Its herbivorous diet, based on ferns, cycads, and low conifers, was consistent with leaf-shaped teeth and a robust lower jaw. As a key early stegosaur on the phylogenetic tree, Huayangosaurus is a genuine link between basal thyreophorans and the Late Jurassic radiation of stegosaurids.

Jurassic Herbivore 4.5m

GB · 130–125 Ma

Hypsilophodon

Hypsilophodon foxii

"High-ridged tooth (from the Isle of Wight)"

Hypsilophodon foxii was a small bipedal ornithopod from the Early Cretaceous of the Isle of Wight, England. Measuring about 1.8 meters in length and weighing just 20 kg, it was an agile, fast-running herbivore adapted for life on savanna-like floodplains. Described by Thomas Henry Huxley in 1869 from a skull collected by Reverend William Fox, the species endured decades of misinterpretation: early 20th-century researchers incorrectly depicted it as an arboreal climber. Peter Galton, in papers published between 1969 and 1974, definitively refuted this hypothesis, establishing Hypsilophodon as a specialized terrestrial runner with long hind legs and a stiff tail for balance.

Cretaceous Herbivore 1.8m

US · 95–83 Ma

Fish Bird

Ichthyornis dispar

"Different fish-bird"

Ichthyornis dispar was a Late Cretaceous seabird that lived on the coasts and islands of the Western Interior Seaway, the vast epicontinental sea that split North America in two between 95 and 83 million years ago. About 60 centimeters long and roughly the weight of a large modern gull, it had fully modern wings, a keeled sternum anchoring robust pectoral muscles, and active flight capability. Yet it retained a striking ancestral trait: small, sharp teeth in its jaws, adapted to grip slippery fish. Described by Othniel Charles Marsh in 1872, it was presented as living proof of Darwinian theory, just thirteen years after the publication of On the Origin of Species. It disappeared in the K-Pg extinction.

Cretaceous Piscivore 0.6m

BE · 126–122 Ma

Iguanodon

Iguanodon bernissartensis

"Iguana tooth from Bernissart"

Iguanodon bernissartensis was one of the first dinosaurs described by science and remains one of the most studied. Initially discovered in 1822 by Gideon Mantell in England and renamed after the extraordinary discovery of 38 complete skeletons in Bernissart, Belgium, in 1878, this Early Cretaceous herbivorous ornithopod measured up to 11 meters and weighed around 4.5 tonnes. Its conical thumb spike is one of its trademarks, and modern biomechanics analyses indicate it was an obligate quadruped. It lived during the Barremian-Aptian (~126–122 Ma) in rich ecosystems of western Europe.

Cretaceous Herbivore 11m

BR · 115–108 Ma

Irritator

Irritator challengeri

"Challenging irritator (named after Professor Challenger)"

Irritator challengeri is a Brazilian spinosaurid discovered in the Romualdo Formation, Araripe Basin, Ceará state. Its name reflects paleontologists' frustration upon finding the original skull had been fraudulently modified by fossil traffickers before reaching scientists. About 8 meters long with an elongated snout lined with conical teeth, it was likely piscivorous, hunting giant fish in the lagoonal environments of the Early Cretaceous of Brazil. The holotype (SMNS 58022), housed in Stuttgart, Germany, is the most complete spinosaurid skull ever found, making Irritator essential for understanding the biology of the entire Spinosauridae family.

Cretaceous Piscivore 8m

TZ · 155–152 Ma

Kentrosaurus

Kentrosaurus aethiopicus

"Spiky lizard of Ethiopia (Africa)"

Kentrosaurus aethiopicus was an African stegosaurid from the Late Jurassic, discovered in the Tendaguru Formation of Tanzania. At roughly 4.5 meters long and up to 1,000 kg, it was smaller than its North American relative Stegosaurus but equally impressive. Its most distinctive feature was the combination of small bony plates on the neck and anterior back with long, sharp spines on the tail and hip region — a formidable defensive arsenal. Biomechanical studies have shown its tail could sweep through a 180-degree arc fast enough to cause serious injury to predators. Originally described by Edwin Hennig in 1915, it is known from hundreds of bones collected during the German expedition to East Africa between 1909 and 1912.

Jurassic Herbivore 4.5m

US · 76.4–75.5 Ma

Kosmoceratops

Kosmoceratops richardsoni

"Richardson's ornate horned face"

Kosmoceratops richardsoni is the ceratopsian with the most elaborate cranial ornamentation ever documented in dinosaur history: a total of 15 horns and bony structures on the skull, including a large downward-curved nasal horn, two supraorbital horns above the eyes, two jugal horns, two laterally-directed epijugal horns, and ten forward-curving apical processes on the parieto-squamosal frill. No other known dinosaur or fossil vertebrate has such dense and diversified cranial ornamentation. The animal lived approximately 76 to 75.5 million years ago during the late Campanian stage of the Cretaceous, in the region corresponding to the present-day state of Utah in the United States. Kosmoceratops belonged to the fauna of the southern portion of Laramidia Island, a large continental island that existed during the Late Cretaceous when the Western Interior Seaway divided North America into two landmasses. Notably, the southern and northern portions of Laramidia were separated by a shallow internal sea and presented completely distinct dinosaur faunas: while the south (where Kosmoceratops lived) had short-frilled ceratopsians with elaborate ornamentation, the north produced forms with longer frills. This geographic faunal difference was one of the central arguments presented by Sampson et al. (2010) in the paper describing the species. The holotype and referred specimens were collected from the Kaiparowits Formation in southern Utah, one of the most productive Late Cretaceous geological units in North America. The formation dates from the late Campanian (~76.6 to 74.5 Ma) and preserves a rich subtropical ecosystem with multiple species of dinosaurs, crocodilians, turtles, lizards, mammals, and amphibians. Kosmoceratops fossils were collected by the Utah Museum of Natural History between 2004 and 2006 at sites within the Grand Staircase-Escalante National Monument. The function of the extravagant cranial ornamentation is a subject of ongoing scientific debate. Sampson et al. (2010) argue that the structures were primarily for intraspecific display and species recognition, analogous to the horns of modern antelopes and cervids. The fact that the supraorbital horns and frill processes face laterally and forward rather than forward in combat position supports the display hypothesis over the defensive one. Later biomechanical analyses by Mallon and Anderson (2013) suggest that ceratopsids used their horns in ritualized intraspecific combat, not as defense against large predators.

Cretaceous Herbivore 4.5m

RU · 168–166 Ma

Kulindadromeus

Kulindadromeus zabaikalicus

"Kulinda runner from Transbaikalia"

Kulindadromeus zabaikalicus is a basal neornithischian from the Middle Jurassic (Bathonian, about 168 to 166 million years ago according to Cincotta et al. 2019) Ukureyskaya Formation, also spelled Ukurey, at the Kulinda locality in the Olov Depression, Chernyshevsky District, Zabaikalsky Krai, southeastern Siberia, Russia. A small bipedal herbivore about 1.5 m long with an estimated mass of 2 kg, it became famous as the first ornithischian with clearly documented complex integumentary cover, a find that unsettled the consensus that feathers were an exclusive trait of coelurosaurian theropods. Godefroit and colleagues, in 2014 in Science, described three types of feather-like filaments at Kulinda: monofilament fuzz covering head and trunk, with simple fibres of constant width comparable to the earliest generation of feather-like structures in Sinosauropteryx; compound tufts of 6 to 7 filaments arising from hexagonal base plates on arms and legs, a previously unknown morphology without exact parallel in theropods; and ribbon-like structures on thigh and tibia, broad, flattened and lacking a defined rachis. Added to these filaments are three scale types: imbricated hexagonal scales on the shins, small rounded scales on hands and feet, and arched rectangular scales on the tail. The simultaneous presence of filaments and scales in the same individual shows that the integumentary morphology of basal dinosaurs was mosaic and suggests that feather-like integument may be plesiomorphic for Dinosauria as a whole rather than restricted to Coelurosauria, radically changing the classical reading that confined feathers to carnivorous theropods. The find overturned the precedent that only Tianyulong and Psittacosaurus bore filamentous structures in Ornithischia, extending the condition to a much older basal ornithischian and geographically anchoring the record in Siberia, outside the Chinese Jehol stage that had dominated feathered fossils. U-Pb dating on detrital zircons and monazites combined with palynology by Cincotta et al. (2019) refined the original age of Godefroit et al. (2014), which pointed to a Bajocian to Tithonian interval (169 to 144 Ma), to Bathonian (168.3 ± 1.3 to 166.1 ± 1.2 Ma), making Kulindadromeus the oldest known dinosaur with unequivocal 'feather-like' structures. The same study synonymised Kulindapteryx ukureica, Daurosaurus olovus and Lepidocheirosaurus natalis, taxa erected by Alifanov and Saveliev in 2014 and 2015 on material from the same bone beds, as nomina dubia likely junior synonyms of Kulindadromeus, simplifying the site's systematics to a single dominant ornithischian taxon. The holotype INREC K3/109, a partial skull with mandibles, is housed at the Institute of Natural Resources, Ecology and Cryology SB RAS in Chita, with referred material distributed across INREC, the Institute of Earth's Crust SB RAS in Irkutsk and the Royal Belgian Institute of Natural Sciences in Brussels, where Paul Spagna prepared the blocks bearing integument. Together, the type skull and the hundreds of disarticulated elements from three bone beds allowed Godefroit and colleagues to reconstruct the animal's nearly complete anatomy and to document the richest record of body cover in a basal ornithischian of the Mesozoic.

Jurassic Herbivore 1.5m

US · 77–74 Ma

Maiasaura

Maiasaura peeblesorum

"Good mother lizard of Peebles"

Maiasaura peeblesorum was a large hadrosaurid that lived during the Late Cretaceous, approximately 77 to 74 million years ago, on the coastal plains of what is now Montana, USA. Described by Jack Horner and Robert Makela in 1979, its name means 'good mother lizard', a direct reference to nesting colonies discovered at Egg Mountain, where eggs, hatchlings, and adults were found together, providing evidence of parental care. With over 200 known specimens across all age ranges, it is one of the best-documented dinosaurs. It is also notable for being the first dinosaur to travel to space.

Cretaceous Herbivore 9m

MG · 70–66 Ma

Majungasaurus

Majungasaurus crenatissimus

"Mahajanga lizard with serrated teeth"

Majungasaurus crenatissimus was the apex predator of Late Cretaceous Madagascar, living 70 to 66 million years ago. Measuring around 7 meters long and over one metric ton, it was a robust-skulled abelisaurid with a unique cranial horn on top of its snout and extremely reduced, vestigial arms. It belonged to a group of Gondwanan theropods that diversified in isolation from the rest of the world. It is notable for being the only non-avian theropod with direct evidence of cannibalism: bones of its own species bear tooth marks identical to those of its jaws.

Cretaceous Carnivore 7m

CN · 161–155 Ma

Mamenchisaurus

Mamenchisaurus constructus

"Horse-gate stream lizard"

Mamenchisaurus constructus is the dinosaur that holds, proportionally, the longest neck of any known animal. Discovered in 1952 during highway construction in Sichuan Province, China, and described in 1954 by paleontologist C. C. Young, this Late Jurassic giant belonged to Mamenchisauridae, an exclusively Asian family of extraordinarily long-necked sauropods. With a total estimated length of 21 to 26 meters and a weight of up to 15 tonnes, it lived in humid subtropical forests bathed by rivers and shallow lakes. Its neck, which could reach more than 9 meters in length, was supported by highly pneumatized cervical vertebrae with a honeycomb-like internal structure that reduced weight without compromising strength.

Jurassic Herbivore 22m

AR · 97–93 Ma

Mapusaurus

Mapusaurus roseae

"Earth lizard (of the rose-colored rocks)"

Mapusaurus roseae was one of the largest terrestrial predators of the Late Cretaceous, inhabiting what is now Argentine Patagonia approximately 97 to 93 million years ago. A member of Carcharodontosauridae, this giant theropod reached 10 to 13 meters in length and weighed between 3 and 6 tonnes. Its skull was deeper and narrower than that of its close relative Giganotosaurus, with characteristic rugose nasals. The discovery of a bonebed containing at least seven to nine individuals of varying ages in the Huincul Formation led researchers to suggest Mapusaurus may have lived and hunted in groups, possibly cooperating to bring down giant prey such as Argentinosaurus.

Cretaceous Carnivore 11m

BR · 85–80 Ma

Maxakalisaurus

Maxakalisaurus topai

"Maxakali people's lizard, of Topá"

Maxakalisaurus topai is a Brazilian titanosaur discovered in the Adamantina Formation, in the Triângulo Mineiro region of Minas Gerais. Described by Kellner et al. in 2006, it is one of the best-documented sauropods from Brazil. About 13 meters long and estimated to weigh 5 tonnes, it had a long neck and tail, ridged teeth (unusual among sauropods), and osteoderms, bony dermal plates. Its name honors the Maxakali indigenous people from the region, and the deity Topá of the Maxakali pantheon. The holotype (MN 5013-V) was on display at the National Museum of Rio de Janeiro until the 2018 fire, which destroyed part of the material. A reconstruction campaign was subsequently launched to restore the skeleton.

Cretaceous Herbivore 13m

GB · 168–164 Ma

Megalosaurus

Megalosaurus bucklandii

"Buckland's great lizard"

Megalosaurus bucklandii holds a unique place in science history: it was the first dinosaur to be formally described, by William Buckland in 1824, eighteen years before Richard Owen coined the word Dinosauria. It lived in the Middle Jurassic of England, around 168 to 164 million years ago, in the coastal areas that today correspond to Oxfordshire and Gloucestershire. It was a medium to large theropod, about 9 meters long and a little over 1 metric ton in body mass. Bipedal, with short but robust forelimbs and recurved serrated teeth, it was the apex predator of its ecosystem. No complete skeleton has ever been found; the species is known from isolated bones in the Taynton Limestone Formation, especially the dentary OUM J13505, designated lectotype in 1990.

Jurassic Carnivore 9m

AR · 93–88 Ma

Megaraptor

Megaraptor namunhuaiquii

"Giant thief of Namunhuaiqui"

Megaraptor namunhuaiquii was a large-bodied theropod of the mid-to-late Cretaceous (Turonian-Coniacian, ~93-88 Ma) found in the Portezuelo Formation of Neuquén, Argentina. Estimated at ~8 meters long and about 1000 kg, Megaraptor was one of the largest predators of its time in South America. The most notable feature — and the one that generated decades of taxonomic debate — is its manual claw: an extraordinarily developed sickle-shaped claw on the first finger of the hand, over 30 cm long, which initially led researchers to interpret the animal as a giant dromaeosaurid (with the claw on the foot), before its true position as a megaraptorid was clarified. The specific name namunhuaiquii refers to Namunhualqui hill, a locality near the discovery site in Neuquén.

Cretaceous Carnivore 8m

CN · 125–120 Ma

Microraptor

Microraptor gui

"Small thief of Gui"

Microraptor gui is one of the most extraordinary dinosaurs ever discovered: a four-winged dromaeosaurid approximately 77 centimeters long and weighing about 1 kilogram, living in what is now Liaoning, China, between 125 and 120 million years ago. Its body was covered in aerodynamically preserved feathers in remarkable detail, including long flight feathers on the hindlimbs as well as the forelimbs. The plumage was iridescent black, similar to that of a modern starling. It is considered fundamental evidence in the debate about the origin of avian flight, demonstrating that the four-surface aerodynamic configuration predated modern birds and was functional in the Early Cretaceous.

Cretaceous Carnivore 0.77m

AU · 119–113 Ma

Minmi

Minmi paravertebra

"From Minmi, with lateral vertebrae (paravertebrae)"

Minmi paravertebra was a small ankylosaur from the Early Cretaceous of Australia, only 3 meters long and weighing around 300 kg. Its most distinctive feature is the paravertebrae: horizontally oriented ossified plates running along the sides of the vertebrae, a structure unique among armored dinosaurs. It was the first thyreophoran discovered in the Southern Hemisphere. A remarkable specimen preserved intact stomach contents, including plant fragments, seeds, and angiosperm fruits, offering a rare window into the diet and ecology of these animals over 110 million years ago.

Cretaceous Herbivore 3m

PT · 152–148 Ma

Miragaia

Miragaia longicollum

"Miragaia (Portuguese village), long neck"

Miragaia longicollum was a Late Jurassic stegosaurid from Portugal, discovered in 1999 by Estevão Dias and the Museu da Lourinhã team during the excavation of a road cutting between the villages of Miragaia and Sobral da Lagoa, in the Lourinhã municipality, Leiria district. The holotype ML 433 was described in 2009 by Octávio Mateus, Susannah Maidment, and Nicolai Christiansen, and immediately drew scientific attention for an unparalleled feature among known stegosaurs: an extraordinarily long neck with at least 17 preserved cervical vertebrae. Most stegosaurids have between 12 and 13 cervicals, a count close to that of many theropods and ornithopods. Miragaia breaks this rule. With its 17 cervicals, it approaches the body plan of a basal sauropodomorph more than the archetypal short-necked, low-headed stegosaur. This independent, parallel convergent evolution with sauropods is one of the most frequently cited examples of convergence among Jurassic herbivores. The animal measured about 6 meters long and weighed roughly 2 tonnes. It belongs to the subfamily Dacentrurinae, which also groups European Dacentrurus and, in some analyses, African Kentrosaurus. The holotype includes a partial skull, lower jaw, a long cervical series, dorsal vertebrae, ribs, pectoral girdle, right humerus, and paired dermal plates along the back. The ecological context is equally remarkable: Miragaia lived in the Iberian archipelago of the Late Jurassic, a mosaic of islands and alluvial plains recorded by the Lourinhã Formation, where it coexisted with the stegosaur Dacentrurus armatus, the large theropods Torvosaurus gurneyi and Allosaurus europaeus, Lourinhanosaurus, and the giant sauropod Lusotitan. The elongated neck suggests exploration of a vegetative stratum distinct from the sympatric Dacentrurus, a niche partitioning hypothesis that helps explain how two stegosaurs of similar size coexisted in the same ecosystem. Miragaia is today one of the most emblematic Portuguese dinosaurs, a symbol of the rich Jurassic record of the Lusitanian Basin and a centerpiece of the Museu da Lourinhã collection.

Jurassic Herbivore 6m

CN · 166–161 Ma

Monolophosaurus

Monolophosaurus jiangi

"Single-crested lizard (of Jiang)"

Monolophosaurus jiangi was a Middle Jurassic tetanuran theropod that lived in what is now Xinjiang Province, northwestern China, approximately 166 to 161 million years ago. At roughly 5 to 5.5 meters long and 475 kg, it was a medium-sized predator distinguished by a large, single cranial crest running along the midline of the snout, formed by the nasal and premaxillary bones. This pneumatized structure was its most remarkable feature, likely used for visual recognition among members of its own species. Known from a single nearly complete holotype, it preserves one of the best-known basal tetanuran skulls in science.

Jurassic Carnivore 5.5m

AR · 221–205 Ma

Mussaurus

Mussaurus patagonicus

"Mouse lizard from Patagonia"

Mussaurus patagonicus is a Late Triassic sauropodomorph that stars in one of paleontology's most unusual stories: it was named the 'mouse lizard' because the first discovered specimens were tiny hatchlings only 20 centimeters long, small enough to fit in the palm of a hand. When José Bonaparte and Martín Vince described the species in 1979, based on these hatchlings from the Los Colorados Formation of Argentine Patagonia, they imagined a modestly sized adult. Decades later, when adult specimens were found and described in detail, it was revealed that Mussaurus grew to 6 meters in length and 1.5 tonnes: one of the largest terrestrial animals of the Late Triassic in South America. This discrepancy between hatchlings and adults is biologically significant. It demonstrates that basal sauropodomorphs underwent dramatic ontogenetic changes not only in size but also in locomotor posture. Mussaurus hatchlings were facultative bipeds, with proportionally similar fore and hind limbs, while adults had more robust forelimbs and likely transitioned to a quadrupedal posture upon reaching large sizes. This pattern echoes what later became obligatory in the giant sauropods of the Jurassic and Cretaceous. The most impactful publication on Mussaurus in recent years was the 2021 study by Otero et al. published in Scientific Reports. Analysis of multiple nests with eggs, neonatal hatchlings, and spatially grouped juveniles revealed strong evidence of gregarious behavior: the animals gathered in age-segregated groups, suggesting some form of parental care or structured social behavior. Mussaurus eggs were preserved in communal nests at a depth suggesting they were buried for incubation, similar to the behavior of crocodiles and some extant birds. This finding pushes the origin of gregarious behavior in sauropodomorphs back to the Triassic, more than 50 million years earlier than previously thought. Phylogenetically, Mussaurus occupies a key position in the transition between solitary basal sauropodomorphs and the large gregarious sauropods of the Mesozoic. The most recent analyses place it within Massopoda, near the base of the clade that will give rise to true Sauropoda. Its body still preserves plesiomorphic features such as a moderately long neck, more robust hind limbs than forelimbs, and simple leaf-shaped teeth, but already shows derived features such as elongated cervical vertebrae and a sauropod-like tarsal formula. The exceptional fossil record of the Los Colorados Formation, with multiple age classes preserved together, makes Mussaurus the most important Triassic sauropodomorph for studies of growth, ontogeny, and social behavior.

Triassic Herbivore 6m

AU · 112–100 Ma

Muttaburrasaurus

Muttaburrasaurus langdoni

"Muttaburra lizard (of Langdon)"

Muttaburrasaurus langdoni was a large herbivorous ornithopod that inhabited eastern Australia during the Early Cretaceous, approximately 112 to 100 million years ago. About 8 meters long and weighing 2.8 tonnes, it was one of Australia's largest dinosaurs. Its most distinctive feature was a hollow, inflatable nasal projection, the bulla nasalis, probably used for vocalizations or display. Its teeth were powerful with shearing edges, adapted for cutting through tough vegetation such as ferns and cycads. It is one of the most complete Australian dinosaurs ever found, with approximately 60% of the skeleton preserved, and became the official fossil emblem of Queensland state in 2022.

Cretaceous Herbivore 8m

US · 68–66 Ma

Nanotyrannus

Nanotyrannus lancensis

"Dwarf tyrant of Lance"

Nanotyrannus lancensis is one of the most controversial dinosaurs in paleontology. Originally described by Charles Gilmore in 1946 as a species of Gorgosaurus, it was reclassified as its own genus by Bakker, Williams, and Currie in 1988. The central debate is whether the known specimens represent a distinct small-bodied tyrannosaurid species or juvenile Tyrannosaurus rex individuals. The 'Jane' specimen (BMRP 2002.4.1), found in Montana in 2001 and housed at the Burpee Museum of Natural History, is the most complete ever attributed to the genus. Recent studies by Longrich and Saitta (2024) and Zanno and Napoli (2025) support its taxonomic validity based on bone histology, skeletal proportions, and independent phylogenetic analysis, though the scientific debate remains active.

Cretaceous Carnivore 5.5m

US · 76–75 Ma

Nasutoceratops

Nasutoceratops titusi

"Big-nosed horned face, honoring Alan Titus"

Nasutoceratops titusi is a centrosaurine ceratopsid dinosaur that lived approximately 76 to 75 million years ago, during the late Campanian of the Cretaceous, in what is now southern Utah in the United States. The animal is immediately recognizable by two extraordinary diagnostic features: supraorbital horns that are extremely long, oriented laterally and curved upward and forward over the eye sockets in a pattern that researchers frequently compare to Texas Longhorn cattle, and a hypertrophied nasal cavity that gives the skull a bulbous, short-snouted appearance. No other known ceratopsid combines these two traits so strikingly, and it was precisely this anatomy without parallel that led the describers to erect not only a new genus and species but a new tribe within Centrosaurinae, the tribe Nasutoceratopsini. The genus name comes from the Latin nasutus, meaning big-nosed, combined with the Greek keratops, horned face. The specific epithet titusi honors Alan L. Titus, the paleontologist at Grand Staircase-Escalante National Monument who supported the field expeditions that led to the discovery. The holotype, catalogued as UMNH VP 16800, was excavated in 2006 by then graduate student Eric K. Lund in the Kaiparowits Formation, within the national monument in Kane County, Utah. The specimen includes a sub-complete skull with mandible, with both supraorbital horns and the nasal region preserved, plus fused cervical vertebrae (syncervical) and associated post-cranial elements. The formal description was published on 10 July 2013 in Proceedings of the Royal Society B by Scott D. Sampson, Eric K. Lund, Mark A. Loewen, Andrew A. Farke, and Katherine E. Clayton. The evolutionary significance of Nasutoceratops extends far beyond its unusual appearance. The species occupies a basal position within Centrosaurinae, retaining the long supraorbital horns characteristic of the common ancestor of Ceratopsidae, while derived centrosaurines such as Centrosaurus, Styracosaurus, and Pachyrhinosaurus dramatically reduced those horns above the eyes and developed, in their place, prominent nasal horns or bosses. This reverses the traditional intuition that long eye horns would be exclusive to chasmosaurines like Triceratops and Kosmoceratops. The tribe Nasutoceratopsini, formalized by Ryan, Holmes, Mallon, and colleagues in 2017, groups Nasutoceratops titusi, Avaceratops lammersi, and Xenoceratops foremostensis, all sharing this combination of short centrosaurine frill with long supraorbital horns and reduced nasal horn. Nasutoceratops titusi is also a central piece in the debate over the intracontinental endemism of Laramidia, the island continent formed in the western portion of North America during the Late Cretaceous, when the Western Interior Seaway divided the continent into two landmasses. The fauna of the Kaiparowits Formation, in southern Utah, contains multiple endemic species that do not appear in contemporary northern formations in Alberta and Montana, and Nasutoceratops is, together with Kosmoceratops richardsoni and Utahceratops gettyi, one of the clearest markers of this pattern. The holotype and the mounted skeleton are on permanent display in the Past Worlds gallery of the Natural History Museum of Utah in Salt Lake City.

Cretaceous Herbivore 4.5m

GB · 130–125 Ma

Neovenator

Neovenator salerii

"New hunter of Salero"

Neovenator salerii was the largest land predator in Europe during the Early Cretaceous, approximately 125 million years ago. Discovered on the Isle of Wight, southern England, it reached 7 to 7.5 meters in length and weighed approximately one metric ton. It is the most complete large theropod known from Europe, with about 70% of the skeleton preserved. As a basal member of Neovenatoridae, a group that includes the enigmatic megaraptors, Neovenator possessed a snout with a complex neurovascular network, indicating high facial sensitivity, possibly used in prey detection.

Cretaceous Carnivore 7.5m

NE · 115–105 Ma

Nigersaurus

Nigersaurus taqueti

"Taquet's Niger lizard"

Nigersaurus taqueti was a rebbachisaurid sauropod from the Middle Cretaceous, discovered in the Elrhaz Formation of Niger in the Sahara. At about 9 meters long and 4 tonnes, it was small by sauropod standards. Its most striking feature was a wide, flat mouth directed straight downward, packed with over 500 replaceable teeth arranged in dental batteries. This extraordinary anatomy allowed it to graze low vegetation with maximum efficiency, like a Cretaceous lawnmower. Formally described by Paul Sereno in 1999, Nigersaurus became one of the most anatomically peculiar dinosaurs ever discovered.

Cretaceous Herbivore 9m

CA · 76–66 Ma

Ornithomimus

Ornithomimus edmontonicus

"Edmonton bird mimic"

Ornithomimus edmontonicus was a Late Cretaceous ornithomimosaur (Maastrichtian, ~76-66 Ma) that inhabited the coastal plains of western North America, in the region corresponding to today's Alberta (Canada) and adjacent US states. About 3.8 meters long and 170 kg, it possessed the morphology that gave the group its name: a toothless horny beak, long flexible neck, long agile hindlimbs, relatively long arms with non-specialized claws, and a rigid tail for balance. This combination is remarkably convergent with modern ostriches (Struthio camelus), which is why ornithomimosaurs are often called 'ostrich dinosaurs'. Ornithomimus edmontonicus is the best-known and most complete species of the genus, with multiple specimens preserved in the Horseshoe Canyon and Hell Creek formations.

Cretaceous Omnivore 3.8m

NE · 125–112 Ma

Ouranosaurus

Ouranosaurus nigeriensis

"Brave lizard from Niger"

Ouranosaurus nigeriensis is one of the most distinctive ornithopods of the Early Cretaceous, famous for its dorsal crest formed by extraordinarily elongated neural spines. It lived approximately 125 to 112 million years ago in the region that now corresponds to Niger, on a warm and humid fluvial floodplain. About 8 meters long and over 2 tonnes, it was a robust herbivore equipped with battery teeth and a uniquely low and elongated skull among iguanodontids. Described by French paleontologist Philippe Taquet in 1976 based on two nearly complete skeletons, it is considered a close relative of hadrosaurs.

Cretaceous Herbivore 8m

MN · 75–71 Ma

Oviraptor

Oviraptor philoceratops

"Egg thief that loves ceratopsians"

Oviraptor philoceratops is one of the most misunderstood dinosaurs in paleontological history. Described by Henry Fairfield Osborn in 1924 from fossils found in the Djadochta Formation of Mongolia, its name means 'egg thief that loves ceratopsians' — an unjust accusation: the animal was actually a devoted parent, brooding its own eggs when it was surprised and buried by a sandstorm 75 million years ago. Around 2 meters long, with a toothless beak, a bony crest on the skull similar to a cassowary, and a feathered body, this agile omnivore inhabited the semiarid forests of the Gobi Desert during the Campanian.

Cretaceous Omnivore 2m

BR · 100.5–93.9 Ma

Oxalaia

Oxalaia quilombensis

"Oxalaia: deity of the waters in Afro-Brazilian religion; quilombensis: from the quilombos of Maranhão"

Oxalaia quilombensis was one of the largest predators of the Late Cretaceous of South America, with an estimated length of 12 to 14 meters. A member of the family Spinosauridae and subfamily Spinosaurinae, it was closely related to the African Spinosaurus aegyptiacus. Known only from jaw fragments collected on Cajual Island, Maranhão, it possessed conical teeth without serrations, a sculptured secondary palate, and a rosette-shaped anterior snout expansion. Its name honors the deity of the waters in Afro-Brazilian religion and the historical quilombos of Maranhão, acknowledging the cultural heritage of the region where it was discovered.

Cretaceous Piscivore 13m

US · 70–66 Ma

Pachycephalosaurus

Pachycephalosaurus wyomingensis

"Thick-headed lizard from Wyoming"

Pachycephalosaurus wyomingensis is the largest and most famous of the pachycephalosaurids, a group of bipedal ornithischian dinosaurs known for the thick bony dome atop their skull. It lived at the end of the Cretaceous, 70 to 66 million years ago, on the coastal plains and angiosperm forests of what is now Montana, Wyoming, South Dakota, and Alberta. Its frontoparietal dome could reach 25 centimeters in thickness, composed of dense fibrolamellar bone. Studies have revealed that Dracorex hogwartsia and Stygimoloch spinifer were actually juvenile forms of the same species. The dome likely functioned in intraspecific combat, similar to modern bighorn sheep.

Cretaceous Herbivore 4.5m

CA · 73–69 Ma

Pachyrhinosaurus

Pachyrhinosaurus canadensis

"Thick-nosed lizard of Canada"

Pachyrhinosaurus canadensis is a Late Cretaceous ceratopsian that broke the rules of its group: instead of a nasal horn, it bore an enormous flattened bony mass called a boss over its nose and eyes. Discovered in the Horseshoe Canyon Formation of Alberta, Canada, and described by Charles Mortram Sternberg in 1950, the animal measured 6 to 8 meters and weighed approximately 3.5 tons. Its enormous bonebeds, containing hundreds of accumulated bones, suggest gregarious behavior in large herds, making it one of the ceratopsians with the strongest evidence for collective social life.

Cretaceous Herbivore 7m

EG · 95–94 Ma

Paralititan

Paralititan stromeri

"Stromer's tidal titan"

Paralititan stromeri is a giant titanosaur from the Cenomanian (about 95 to 94 million years ago) of the Bahariya Formation in the Bahariya Oasis of Egypt's Western Desert. It was described in 2001 by Joshua B. Smith, Matthew C. Lamanna, Kenneth J. Lacovara, Peter Dodson and colleagues in Science, based on holotype CGM 81119, a fragmentary but significant skeleton including two humeri (the right complete, at 1.69 metres long among the largest ever recovered in a Cretaceous sauropod at the time of description), two sacral vertebrae likely the fifth and sixth, an anterior caudal vertebra, dorsal and sacral ribs, incomplete scapulae and the distal end of a metacarpal. With only around 5 per cent of the skeleton preserved, Paralititan's dimensions are estimated by comparison with more complete relatives. Carpenter (2006) calculated about 26 metres in length using Saltasaurus as guide, while mass estimates vary widely depending on method, between 20 tonnes (Paul 2010), roughly 30 tonnes (Wikipedia, April 2026 revision), 50 tonnes (Gonzalez Riga et al. 2016, via humerus and femur circumference), 30 to 55 tonnes (Paul 2019) and 59 tonnes (2011 estimate). All these values are approximate and reflect the uncertainty intrinsic to fragmentary preservation. The animal lived in a coastal mangrove ecosystem, the first dinosaur scientifically demonstrated to inhabit this type of environment. The deposit preserving the holotype is a tidal flat dominated by the seed fern Weichselia reticulata, and a Carcharodontosaurus tooth associated with the skeleton suggests immediate scavenging of the carcass by a giant predator. Villa et al. (2022), in the description of Abditosaurus kuehnei, recovered Paralititan in an Afro-European clade within Saltasaurinae with Abditosaurus, sister to the South American Saltasaurini clade including Neuquensaurus and Saltasaurus; earlier analyses, such as Curry Rogers (2005) and Mannion and Upchurch (2011), had interpreted the genus as a more basal titanosaur. The Bahariya Oasis is the same site where Austro-Hungarian collector Richard Markgraf gathered fossils between 1912 and 1914, later described by Ernst Stromer in Munich; the rediscovery of the site by Joshua Smith's team in 2000 marked the return of palaeontology to North Africa after nearly 70 years of silence.

Cretaceous Herbivore 26m

CA · 76.5–73 Ma

Parasaurolophus

Parasaurolophus walkeri

"Lizard with a crest parallel to Saurolophus (walkeri species)"

Parasaurolophus walkeri is one of the most recognizable dinosaurs of the Late Cretaceous, famous for the extraordinary hollow tubular crest that projected backward from the skull, potentially exceeding one meter in length. A social herbivore with compact rows of hundreds of replacement teeth, it lived in herds on the coastal plains of North America approximately 75 million years ago. The crest likely functioned as an acoustic resonating chamber, enabling low-frequency vocalizations for intraspecific communication. Facultatively bipedal, it alternated between upright stance and four-legged locomotion.

Cretaceous Herbivore 9.5m

AR · 102–100 Ma

Patagotitan

Patagotitan mayorum

"Patagonian titan (of the Mayo family)"

Patagotitan mayorum is one of the largest land animals that ever existed, a colossal titanosaur discovered in 2010 in Argentine Patagonia. With estimates of up to 37 meters in length and 69 tonnes in weight, it rivaled or surpassed Argentinosaurus for the title of largest dinosaur of all time. Six partial skeletons were excavated between 2013 and 2015 from the Cerro Barcino Formation in Chubut, providing one of the most complete fossil records of a giant titanosaur. Formally described by Carballido et al. in 2017, the animal belongs to the clade Lognkosauria and lived approximately 101 million years ago.

Cretaceous Herbivore 37m

MN · 80–75 Ma

Pinacosaurus

Pinacosaurus grangeri

"Plank lizard of Granger"

Pinacosaurus grangeri is a medium-sized ankylosaurid from the Late Cretaceous (Campanian, about 80 to 75 million years ago) of the Djadokhta Formation of Mongolia and the Bayan Mandahu Formation of Inner Mongolia, China, with older records from the Alagteeg Formation. It was described by Charles W. Gilmore in 1933 based on holotype AMNH 6523, collected in 1923 at Shabarakh Usu (today Bayn Dzak, 'Flaming Cliffs') by palaeontologist Walter Granger during the Central Asiatic Expeditions led by Roy Chapman Andrews. It reached about 5 metres in length and 1.9 tonnes in body mass. The skull was low and broad, with a toothless beak, weakly developed squamosal horns, four pyramidal occipital horns and a series of accessory narial openings perforating the premaxilla, a diagnostic feature of the genus. The body was covered with keeled polygonal osteoderms, with two cervical half rings protecting the neck and a tail ending in a bony club. The genus contains two valid species: P. grangeri (Mongolia and China) and P. mephistocephalus (Godefroit et al., 1999), distinguished by 'devil-like' squamosal horns projecting far beyond the skull roof. Pinacosaurus is best known for the extraordinary juvenile bonebeds of Alag Teeg (Mongolia) and Bayan Mandahu (China), with about 100 partially articulated immature skeletons preserved together, direct evidence of gregarious behaviour in young ankylosaurs. In 2023, Yoshida, Kobayashi and Norell described in Communications Biology the first preserved laryngeal apparatus in a non-avian dinosaur, also in Pinacosaurus, suggesting bird-like vocalisation.

Cretaceous Herbivore 5m

DE · 214–204 Ma

Plateosaurus

Plateosaurus engelhardti

"Engelhardt's flat lizard"

Plateosaurus engelhardti is the most abundant dinosaur of the European Triassic and one of the earliest large herbivores in dinosaur history. Described by Hermann von Meyer in 1837, it is known from hundreds of specimens collected in Germany, Switzerland, and France, making it one of the best-documented species in the fossil record. Up to 10 meters long and over 4 tonnes, it was an obligate biped, unable to use its hands for quadrupedal locomotion. Its bone histology revealed a unique growth pattern: individuals of the same species could reach very different body sizes depending on environmental conditions, a phenomenon called developmental plasticity.

Triassic Herbivore 8m

NO · 150–145 Ma

Pliosaurus

Pliosaurus funkei

"Funke's lizard (honoring Bjørn Funke, discoverer of the holotype)"

Pliosaurus funkei, nicknamed Predator X before its formal scientific description, is one of the largest marine predatory reptiles ever discovered. It lived in the Tithonian (latest Jurassic, around 150 to 145 million years ago) in the shallow seas of the primitive Arctic, today the Svalbard archipelago, Norway. Initial estimates of 15 meters were revised downward, placing the animal at 10 to 12 meters and around 11 metric tons. Its mandible was among the largest of any marine predator ever found, and its especially elongated forelimbs suggest powerful propulsion. Discovered between 2004 and 2012 by the team of Jørn Hurum, Patrick Druckenmiller and Espen Knutsen, it was formally named in 2012 in honor of Bjørn Funke and May-Liss Knudsen Funke.

Jurassic Carnivore 10m

NL · 70–66 Ma

Prognathodon

Prognathodon saturator

"Jaw-toothed satiator (from Latin saturator, the one who satisfies)"

Prognathodon saturator was one of the largest and most powerfully built mosasaurs that ever existed. It lived at the end of the Cretaceous, between ~70 and 66 million years ago, in the shallow seas that covered what is now the Maastricht region of the Netherlands and Belgium. At up to 12 meters long and estimated at 5 to 7 tonnes, it shared the same waters as the famous Mosasaurus hoffmannii. Unlike M. hoffmannii, a generalist hunter, P. saturator had a massive skull and extremely robust jaws, considered the strongest of any known mosasaur. Its short, conical, blunt-tipped teeth were adapted to crush hard prey: sea turtles, thick-shelled ammonites, large fish and possibly other mosasaurs. It was not a dinosaur but a squamate reptile (Squamata), a distant relative of modern monitor lizards and snakes. The holotype, specimen NHMM 1998141, was discovered in 1998 at the ENCI quarry, received the affectionate nickname Bèr, and today rests inside a special glass structure in the courtyard of the Natuurhistorisch Museum Maastricht.

Cretaceous Carnivore 12m

MN · 75–71 Ma

Protoceratops

Protoceratops andrewsi

"First horned face (of Andrews)"

Protoceratops andrewsi was a small quadrupedal ceratopsian that lived in the deserts of Central Asia during the Campanian, between 75 and 71 million years ago. About 1.8 meters long and 180 kg, it had a powerful horned beak, a prominent parieto-squamosal frill, and lacked true horns unlike its later relatives. Extraordinarily abundant in the Djadochta Formation, it is known from dozens of specimens at all growth stages from hatchlings to adults, making it one of the most studied dinosaurs in terms of ontogeny. Its fame extends beyond science thanks to the famous Fighting Dinosaurs fossil, in which it appears locked in combat with Velociraptor mongoliensis.

Cretaceous Herbivore 1.8m

MN · 125–100 Ma

Psittacosaurus

Psittacosaurus mongoliensis

"Mongolian parrot lizard"

Psittacosaurus mongoliensis is one of the most primitive known ceratopsians and simultaneously the dinosaur represented by the greatest number of individual specimens in the world. It lived during the Early Cretaceous, between 125 and 100 million years ago, in Central Asia. Roughly two meters long and up to 20 kg, it was relatively small: hatchlings were born under 13 cm in length. Its most distinctive feature is the curved, parrot-like horny beak that gave it its name. Rigid bristles on the tail and scales preserved in exceptional specimens provide unique insights into the actual appearance of dinosaurs.

Cretaceous Herbivore 2m

BR · 75–70 Ma

Pycnonemosaurus

Pycnonemosaurus nevesi

"Neves's dense forest lizard"

Pycnonemosaurus nevesi was the largest known abelisaurid dinosaur, estimated at 8.9 meters in length and approximately 3.6 metric tons. It lived during the Late Cretaceous, roughly 70 to 75 million years ago, in what is now Mato Grosso State, Brazil. Described by Kellner and Campos in 2002, it was the first confirmed abelisaurid from the Bauru Group. It belongs to the Furileusauria lineage of South American abelisaurids, the same group that includes Carnotaurus and Aucasaurus. Its fragmentary fossils reveal a large predator that likely preyed on titanosaur sauropods sharing its environment.

Cretaceous Carnivore 8.9m

CN · 72–66 Ma

Qianzhousaurus

Qianzhousaurus sinensis

"Chinese lizard of Qianzhou"

Qianzhousaurus sinensis is a long-snouted tyrannosaurid from the end of the Cretaceous, recovered in 2010 during excavation at a construction site near the city of Ganzhou, in Jiangxi Province, southern China. The species was formally described in 2014 by Lü Junchang, Yi Laiping, Stephen L. Brusatte, Yang Ling, Hu Hailu and Chen Liu, in a paper published in Nature Communications. The type material, catalogued as GM F10004 and housed at the Ganzhou Museum, includes a nearly complete skull and part of the postcranial skeleton, comprising cervical, sacral and caudal vertebrae, along with hindlimb elements. The holotype individual, still a subadult, reached about 6.3 metres in length and approximately 2 metres in hip height, with an estimated mass between 750 and 757 kilograms; estimates based on allometric comparison with Tarbosaurus bataar and Alioramus suggest that full adults could have reached 7.5 or even 9 metres, although this figure is inferred and not directly supported by fossils. The animal's most striking feature is its extremely elongated and shallow skull, with a narrow premaxilla, rows of long banana-shaped teeth, paired nasal crests forming bumps on top of the snout and a pneumatic opening on the maxilla, features that clearly distinguish it from short-snouted tyrannosaurines such as Tyrannosaurus and Tarbosaurus. Lü et al. 2014 erected the tribe Alioramini to group Qianzhousaurus, Alioramus altai and Alioramus remotus, all gracile long-snouted tyrannosaurines from the Late Cretaceous of Asia. The phylogenetic analysis of Brusatte and Carr 2016, published in Scientific Reports, confirmed this grouping and placed Alioramini as the sister lineage to the massive tyrannosaurines represented by Tarbosaurus and Tyrannosaurus, showing that there was significant ecological diversity among Asian apex predators at the end of the Cretaceous. The set of dental features, with 18 or more teeth in the dentary and narrower teeth than those of the robust tyrannosaurines, suggests a differentiated diet, possibly focused on smaller, nimbler or softer-bodied prey, in contrast to the bone-crushing strategy documented in Tarbosaurus. The animal lived at the same time and broadly in the same region as Tarbosaurus bataar in Mongolia, which supports the hypothesis of ecological niche partitioning between long-snouted and short-snouted tyrannosaurines. The Nanxiong Formation, where the holotype was recovered, also preserves dinosaur eggs, tracks and a rich fauna of oviraptorosaurs, titanosaurs and small theropods, suggesting warm humid fluvial plains in a continental setting of southern China. The nickname 'Pinocchio rex', coined by the international press, popularly summarises the anatomical difference between the slender snout of Qianzhousaurus and the massive snout of its North American cousins. The discovery also reinforced the view that Tyrannosauridae was an ecologically diverse clade, with lineages specialised in different predation strategies, and not only in bone-crushing bites. As of 2026, no referred specimens have been published in peer-reviewed literature, so all known anatomy of the taxon derives exclusively from the holotype, which makes new discoveries in southern China particularly relevant for testing estimates of maximum size and ontogenetic variation of Qianzhousaurus sinensis.

Cretaceous Carnivore 6.3m

IN · 69–66 Ma

Rajasaurus

Rajasaurus narmadensis

"Regal lizard from the Narmada"

Rajasaurus narmadensis was the apex terrestrial predator of the Indian subcontinent during the Late Cretaceous. It lived between 69 and 66 million years ago in what is now Gujarat state, northwestern India, in an arid-to-semi-arid environment crossed by seasonal rivers and punctuated by the volcanic episodes of the Deccan Traps. The only Indian abelisaurid with well-preserved postcranial remains, it was distinguished by a median sagittal crest atop the skull, unique among Indian abelisaurids. Its placement within Majungasaurinae confirms the biogeographic connection between India and Madagascar in the Late Cretaceous.

Cretaceous Carnivore 6.6m

MG · 70–66 Ma

Rapetosaurus

Rapetosaurus krausei

"Rapeto's lizard (Krause)"

Rapetosaurus krausei is a medium-sized titanosaur from the Maastrichtian (about 70 to 66 million years ago) of the Maevarano Formation in northwestern Madagascar. Described by Kristina Curry Rogers and Catherine Forster in 2001 from holotype UA 8698 (partial adult skull) and the referred juvenile skeleton FMNH PR 2209, reaching about 8 metres in the immature individual and estimated 15 to 16.5 metres and roughly 10 tonnes for adults, it is the most complete titanosaur ever found and the first with a skull articulated to the skeleton. The skull combines diplodocoid features (elongated, with retracted external nares) with macronarian ones (pencil-like teeth restricted to the anterior portion), while the postcranial skeleton is clearly titanosaurian, with procoelous caudal vertebrae, a saddle-shaped pelvis, crescent-shaped sterna and pneumatic dorsal ribs. Curry Rogers et al. (2016, Science) described a post-hatchling (MAD 07-17) of only around 40 kg and 35 cm at the hip, and inferred precocial habits with limb isometry and rapid cortical remodelling. Curry Rogers and Kulik (2018) detailed the genus's osteohistology in 25 growth-series elements, confirming highly vascularised fibrolamellar tissue and rapid growth. The genus represents the final record of sauropod dinosaurs in Madagascar, alongside Vahiny depereti (Curry Rogers and Wilson 2014).

Cretaceous Herbivore 15m

NE · 99–93 Ma

Rugops

Rugops primus

"First wrinkle face"

Rugops primus is a basal abelisaurid from the Late Cretaceous, discovered in the Echkar Formation of Niger, at the heart of the Sahara Desert. It lived approximately 95 million years ago, during a period when Gondwana was still fragmenting. Its partial skull, roughly 31 centimeters long, features a surface covered with vascular foramina and depressions on the nasal bones — unique structures that likely supported crests, cornified scales, or dermal ornaments in life. Its relatively small teeth led some researchers to propose scavenging behavior, though this hypothesis remains debated. As one of the first well-documented African abelisaurids, Rugops provided key evidence for faunal connections between Gondwanan landmasses during the mid-Cretaceous.

Cretaceous Carnivore 6m

AR · 70–66 Ma

Saltasaurus

Saltasaurus loricatus

"Lizard from Salta, protected by armored plates"

Saltasaurus loricatus is an Upper Cretaceous titanosaur from Argentina and one of the most important sauropods in South American paleontology. Described by Bonaparte and Powell in 1980 from fossils of the Lecho Formation in Salta Province, it was the first sauropod confirmed with dermal armor: oval-plate osteoderms and rounded ossicles covering the back. With a relatively short neck and robust limbs, it inhabited fluvial-lacustrine plains. Mass nesting evidence at Auca Mahuevo, from closely related saltasaurines, suggests gregarious reproductive behavior for the group.

Cretaceous Herbivore 9m

BR · 113–110 Ma

Santanaraptor

Santanaraptor placidus

"Santana raider, placid"

Santanaraptor placidus is a small coelurosaurian theropod from the Early Cretaceous (Aptian-Albian, ~110 Ma) Romualdo Formation (formerly the 'Romualdo Member' of the Santana Formation) of the Araripe Basin in southern Ceará, Brazil. The holotype MN 4802-V is famous for preserving fossilized soft tissue — muscle fibres, epidermis and possible blood vessels — which prompted one of the first dinosaur soft-tissue reports, published by Alexander Kellner in Nature in 1996. Formally described in 1999 as a basal coelurosaur, it was later reinterpreted as a tyrannosauroid (Holtz 2004; Delcourt and Grillo 2018) and, most recently, redescribed as a basal maniraptoromorph by Delcourt and colleagues in 2025. The juvenile holotype survived the September 2018 Museu Nacional fire and remains a reference specimen for studies of exceptional preservation and small-theropod diversity in Brazil.

Cretaceous Carnivore 1.5m

BR · 233–229 Ma

Saturnalia

Saturnalia tupiniquim

"Saturnalia, tupiniquim (Brazilian)"

Saturnalia tupiniquim is one of the oldest known dinosaurs in the world, living approximately 233 million years ago in what is now Rio Grande do Sul, Brazil. At roughly 1.5 meters in length and an estimated weight between 4 and 11 kilograms, it was a small bipedal animal. Described in 1999 by Max Cardoso Langer, Fernando Abdala, Martha Richter, and Michael Benton, it is classified as one of the most basal sauropodomorphs on the evolutionary tree, representing a critical transition between primitive carnivorous dinosaurs and the future giant herbivores like sauropods. Its diet likely included insects and small vertebrates, indicating that the earliest sauropodomorphs were not yet exclusive herbivores. The name honors the Roman Saturnalia festival, celebrated at the time of discovery.

Triassic Omnivore 1.5m

US · 115–108 Ma

Sauropelta

Sauropelta edwardsorum

"Edwards's lizard shield"

Sauropelta edwardsorum was one of the largest nodosaurids of the Early Cretaceous in North America. Measuring approximately 5.2 to 6 meters in length and weighing up to 2 metric tons, it was a heavily armored herbivore from the Cloverly Formation of present-day Wyoming and Montana. Its most distinctive feature was a row of enormous lateral spines along its neck and shoulders that increased progressively in size toward the torso. Unlike ankylosaurids, it lacked a tail club, but its body was densely covered with osteoderms. The long tail, composed of more than fifty vertebrae, accounted for nearly half the animal's total length. Described by John Ostrom in 1970, it is considered one of the best-understood nodosaurids in science.

Cretaceous Herbivore 5.5m

US · 115–108 Ma

Sauroposeidon

Sauroposeidon proteles

"Poseidon lizard, before-complete"

Sauroposeidon proteles was a giant titanosauriform sauropod that lived in the Early Cretaceous of North America, between approximately 115 and 108 million years ago, during the Aptian and Albian stages. The name, chosen by Mathew Wedel in 2000, combines the Greek sauros (lizard) with Poseidon, the Greek god of the seas and also known as the Earth-shaker, in reference to the seismic impact that an animal of this mass would produce while walking. The specific epithet proteles means complete before the end and was chosen because Sauroposeidon is the last large brachiosaur-grade sauropod known from North America before the sauropod hiatus that marks most of the mid-Early Cretaceous on the continent. Length estimates range between 27 and 34 meters, with typical values near 30 meters, while body mass is estimated between 40,000 and 60,000 kg, with 45,000 kg being the most frequently cited figure. All these estimates are extrapolated from a partial cervical series, as no complete skeleton of the taxon exists. The holotype OMNH 53062 consists of four articulated cervical vertebrae (C5 to C8), each approximately 1.25 to 1.4 meters long, the longest sauropod cervical vertebrae ever measured at the time of the original description. The vertebrae show extreme pneumaticity, with more than 89% of internal volume occupied by air chambers, an adaptation that drastically reduced neck mass and made an animal with cervical bones of this dimension biomechanically viable. Matthew Wedel, a graduate student at the University of Oklahoma when he recognized the material in 1999, used Sauroposeidon's pneumaticity as the basis for two decades of research on air sacs and respiratory physiology of sauropods, with implications for understanding the origin of bird airways. The taxon's phylogenetic position has been significantly revised since its original description. Wedel, Cifelli and Sanders initially classified Sauroposeidon as a derived brachiosaurid, the youngest of the group in North America. Later cladistic analyses by D'Emic (2012) and D'Emic and Foreman (2012), confirmed by Mannion et al. (2013), repositioned the genus within basal Somphospondyli, outside Brachiosauridae, as a taxon close to the base of Titanosauria. D'Emic and Foreman (2012) also synonymized Paluxysaurus jonesi Rose (2007), from the Twin Mountains Formation in Texas, with Sauroposeidon, substantially expanding the known material of the taxon. The Fort Worth Museum of Science and History mount, originally displayed as Paluxysaurus, is today the only substantially complete mounted skeleton attributed to Sauroposeidon. Sauroposeidon's paleoecology is associated with the Antlers Formation, in Oklahoma, and contemporary formations such as Twin Mountains (Texas) and Cloverly (Wyoming). The environment was one of humid subtropical coastal plains, with conifer and cycad forests near a shallow epicontinental sea. Contemporaries included the giant theropod Acrocanthosaurus atokensis, the main predator of the ecosystem, the dromaeosaurid Deinonychus antirrhopus and the ornithopod Tenontosaurus tilletti, its preferred prey. Another titanosauriform sauropod, Astrodon, occurred in nearby Early Cretaceous formations. Sauroposeidon's maximum foraging height, estimated at 17 to 18 meters with the neck raised, would position it among the tallest dinosaurs ever documented, possibly the tallest known.

Cretaceous Herbivore 30m

GB · 196–183 Ma

Scelidosaurus

Scelidosaurus harrisonii

"Limb lizard"

Scelidosaurus harrisonii is one of the oldest and most complete armored dinosaurs known to science. It lived during the Early Jurassic, approximately 196 to 183 million years ago, along the shores of what is now southwestern England. Roughly 4 meters long and 270 kg, it was a quadrupedal herbivore covered by horizontal rows of oval osteoderms along its neck, back, and tail. Its skull bore horny scutes, occipital horns, and unique bony structures found in no other dinosaur. Originally described by Richard Owen in 1861, Scelidosaurus holds a key position in the evolution of thyreophoran dinosaurs, ancestral to the ankylosaurs.

Jurassic Herbivore 4m

IT · 115–110 Ma

Scipionyx

Scipionyx samniticus

"Scipio's claw of the Samnites"

Scipionyx samniticus is the only Italian dinosaur with preserved internal organs, earning it the affectionate nickname 'Ciro'. Discovered in 1981 near Pietraroja, in Campania, the only known specimen is a juvenile just 24 centimeters long, fossilized about 113 million years ago in limestone from a shallow lagoon. The three-dimensional preservation of intestine, trachea, liver, and muscle tissues through calcium phosphatization is unprecedented among dinosaurs. Estimated adults would have reached about 2 meters in length. Its phylogenetic placement within Compsognathidae is accepted by most researchers, though debate persists because the specimen is a neonate.

Cretaceous Carnivore 2m

CN · 168–161 Ma

Shunosaurus

Shunosaurus lii

"Li's lizard of Shu"

Shunosaurus lii is a medium-sized basal eusauropod from the Middle Jurassic (Bathonian to Callovian, about 168 to 161 million years ago) of the Lower Shaximiao Formation, Sichuan Basin, southwestern China. It was described by Dong Zhiming, Zhou Shiwu and Zhang Yihong in 1983, based on holotype IVPP V.9065 collected at the Dashanpu locality in Zigong municipality. It reached about 9.5 metres in length and three tonnes in body mass. It had a relatively short neck for a sauropod, with 12 or 13 cervical vertebrae, a low elongated skull with a truncated snout, cylindrical to spatulate teeth and jaws strongly curved upwards. Its most remarkable feature is a bony tail club formed by fused distal caudal vertebrae and topped by two pairs of conical osteoderms, the only sauropod known to possess such a structure. About twenty additional specimens have been collected at Dashanpu, including complete skeletons, skulls and juveniles, making Shunosaurus one of the best anatomically known sauropods, with roughly 94% of skeletal elements identified. The species dominates the Dashanpu fauna, accounting for about 90% of sauropod fossils at the site.

Jurassic Herbivore 9.5m

CN · 125–122 Ma

Sinosauropteryx

Sinosauropteryx prima

"First Chinese reptile wing"

Sinosauropteryx prima is one of the most revolutionary dinosaurs in the history of paleontology. Discovered in 1996 in the Yixian Formation of Liaoning, China, it was the first confirmed non-avian dinosaur with feather-like structures. At only 1.07 meters long and less than 600 grams, it was an agile predator of small lizards and mammals. In 2010, it became the first dinosaur to have its true colors scientifically confirmed: ginger and white stripes on the tail and a dark mask around the eyes, revealed through analysis of fossilized melanosomes.

Cretaceous Carnivore 1.07m

EG · 99–93 Ma

Spinosaurus

Spinosaurus aegyptiacus

"Egyptian spine lizard"

Spinosaurus aegyptiacus was the largest theropod ever recorded, surpassing Tyrannosaurus rex in length. At up to 15 meters and an estimated mass between 6,000 and 7,400 kg, it dominated the river systems of northern Africa during the Cenomanian (99 to 93 million years ago). Its most striking feature was the dorsal sail supported by neural spines up to 1.65 meters tall, whose function is still debated: thermoregulation, sexual display, or fat storage. The snout was elongated and narrow, with conical teeth adapted for catching fish, resembling the morphology of modern crocodilians. Pressure receptors in the snout, similar to those in crocodiles, allowed it to detect prey underwater. In 2020, Ibrahim and colleagues described a paddle-like tail with tall neural spines and expanded chevrons, confirming adaptations for propulsive swimming. Spinosaurus is the only non-avian dinosaur with robust evidence of aquatic habits. The original fossils, collected by Markgraf in Egypt in 1912, were destroyed in the Allied bombing of the Munich Museum in 1944, making rediscoveries in Morocco essential for reconstructing the animal.

Cretaceous Piscivore 15m

BR · 233–225 Ma

Staurikosaurus

Staurikosaurus pricei

"Southern Cross lizard, honoring Llewellyn Ivor Price"

Staurikosaurus pricei is one of the most primitive carnivores known, living approximately 233 to 225 million years ago in what is now Rio Grande do Sul, Brazil. At roughly 2.1 meters long and 30 kilograms, it was a medium-sized bipedal predator for its time. Its serrated, backward-curving teeth indicate an active carnivorous diet. Described by Edwin Colbert in 1970 from holotype MCZ 1669, its phylogenetic position remains debated: sometimes classified in Herrerasauridae, sometimes as an even more basal dinosaur. It is one of the most important animals for understanding the earliest stages of dinosaur evolution.

Triassic Carnivore 2.1m

US · 155–150 Ma

Stegosaurus

Stegosaurus armatus

"Armored roof lizard"

Stegosaurus armatus is one of the most recognizable dinosaurs of the Jurassic, famous for its two alternating rows of dorsal bony plates and four tail spikes, the so-called thagomizer. It lived approximately 155 to 150 million years ago in the Morrison Formation of the western United States. Up to 9 meters long and weighing around 5,400 kg, it was a large herbivore that browsed low vegetation with small teeth and a horny beak. Its brain was proportionally tiny, roughly 80 grams. The dorsal plates, sheathed in keratin, were likely used for visual recognition between individuals and possibly for thermoregulation. Fóssil evidence confirms the thagomizer was an effective defensive weapon: an Allosaurus vertebra was found with a puncture matching Stegosaurus spike dimensions, with healed bone around the wound.

Jurassic Herbivore 9m

CA · 75.5–74.5 Ma

Styracosaurus

Styracosaurus albertensis

"Spiked lizard of Alberta"

Styracosaurus albertensis was a centrosaurine ceratopsid that lived during the Late Campanian stage of the Cretaceous, approximately 75 million years ago, in what is now the province of Alberta, Canada. Measuring roughly 5.5 meters in length and weighing about 2.7 metric tons, it was distinguished by an elaborately ornamented skull featuring a nasal horn up to 60 centimeters long and a parietal frill bearing up to six long posterior spikes. These structures likely functioned in intraspecific recognition and mate attraction. Large fossil accumulations suggest the animals lived in herds and may have migrated seasonally across Campanian coastal environments.

Cretaceous Herbivore 5.5m

NE · 125–112 Ma

Suchomimus

Suchomimus tenerensis

"Crocodile mimic from Ténéré"

Suchomimus tenerensis was a giant spinosaurid of the Early Cretaceous, reaching around 10 to 11 meters in length and up to 3.5 metric tons. Its elongated, narrow snout resembling a crocodile's, and its row of conical teeth adapted for gripping slippery fish, made it a specialized piscivore. The large curved thumb claws, up to 19 centimeters long, were its primary weapons for hooking aquatic prey. It lived on tropical floodplains in what is now Niger, coexisting with the giant crocodyliform Sarcosuchus and sauropods such as Nigersaurus. It was described in 1998 by Paul Sereno and colleagues from fossils found in the Ténéré Desert.

Cretaceous Piscivore 10.5m

US · 153–150 Ma

Supersaurus

Supersaurus vivianae

"Super lizard"

Supersaurus vivianae is one of the longest dinosaurs ever discovered, with estimates ranging between 33 and 40 meters in length. A diplodocid sauropod of the Late Jurassic, it lived in the ecosystems of the Morrison Formation in western North America approximately 153 to 150 million years ago. Its extremely long neck, supported by specialized cervical vertebrae, allowed it to reach vegetation over large areas without moving its body. The longest known cervical vertebra measures 1.38 meters. With an estimated mass of 35 to 44 tonnes, it combined colossal size with efficient ossification, thanks to an air sac system similar to that of birds.

Jurassic Herbivore 33m

BR · 125–113 Ma

Tapuiasaurus

Tapuiasaurus macedoi

"Tapuia lizard (Macedo)"

Tapuiasaurus macedoi is a mid-sized titanosaur (~13 m, ~10 tonnes) from the Early Cretaceous (Aptian, ~120 Ma) Quiricó Formation, Areado Group, Sanfranciscana Basin, in northern Minas Gerais, Brazil. The holotype MZSP-PV 807, curated at the Museu de Zoologia da USP, is renowned for preserving the only nearly complete Early Cretaceous titanosaur skull known worldwide, combined with an articulated partial postcranial skeleton. Its 'diplodocoid-like' cranial anatomy, with elongated rostrum, pencil-shaped cylindrical teeth and retroposed nares, pushed back by up to 30 million years the radiation of advanced titanosaurs that literature had assumed was restricted to the Late Cretaceous. Described in 2011 by Hussam Zaher and colleagues in PLOS ONE and cranially redescribed by Wilson, Pol, Carvalho and Zaher in 2016, the taxon is now a key piece for understanding the early evolution of Titanosauria in Gondwana.

Cretaceous Herbivore 13m

MN · 72–66 Ma

Tarbosaurus

Tarbosaurus bataar

"Alarming lizard, hero"

Tarbosaurus bataar was the largest land predator in Asia at the end of the Cretaceous, 72 to 66 million years ago. At up to 10 to 12 meters long and around 5 metric tons, it was the Asian equivalent of Tyrannosaurus rex, with whom it shared close kinship within the subfamily Tyrannosaurinae. Its skull measured approximately 1.3 meters, proportionally narrower than that of T. rex, with more laterally oriented orbits resulting in a reduced binocular field. The forelimbs were proportionally even smaller than those of T. rex, with only two functional digits. Known from over 30 specimens, including more than 15 skulls and several complete postcranial skeletons, Tarbosaurus is one of the best-represented tyrannosaurids in the fossil record. Its remains come exclusively from the Nemegt Formation of Mongolia and the Subashi Formation of China.

Cretaceous Carnivore 10m

GB · 200–183 Ma

Temnodontosaurus

Temnodontosaurus platyodon

"Flat-toothed cutting-tooth lizard"

Temnodontosaurus platyodon was one of the largest ichthyosaurs of the Early Jurassic, a marine reptile about 9 meters long that inhabited the seas of what is now Europe roughly 200 to 183 million years ago. It looked like a mix of dolphin, fish, and lizard, with a streamlined body, a bilobed tail fluke, four flippers, and an elongated snout filled with robust teeth. It was the first ichthyosaur to be scientifically described, based on a specimen found by Joseph and Mary Anning at Lyme Regis (England) between 1811 and 1812. It had the largest relative eyes ever documented in any vertebrate, the size of footballs, adapted for hunting in deep, dimly lit waters. It fed on fish, cephalopods, and even other ichthyosaurs.

Jurassic Piscivore 9m

US · 115–108 Ma

Tenontosaurus

Tenontosaurus tilletti

"Tillett's sinew lizard"

Tenontosaurus tilletti was a medium-sized iguanodontian ornithopod that lived during the Aptian-Albian of the Early Cretaceous, approximately 115 to 108 million years ago, in what is now the western United States. At 6 to 7.5 meters in length and estimated body mass of 700 to 1,000 kg, it was one of the most common and abundant herbivores of its time and region. The genus is morphologically distinct from other ornithopods by its extraordinarily long and robust tail, which in adults could represent more than half the total length of the animal. The caudal vertebrae are reinforced by ossified tendons, hence the name 'sinew lizard', which provided rigidity to the tail and possibly functioned as a counterweight to maintain balance during bipedal or quadrupedal locomotion. Tenontosaurus was capable of moving both on two and four legs depending on speed and terrain. The paleontological importance of Tenontosaurus extends far beyond its intrinsic morphology: the animal is the center of the longest and most influential debate in paleontology about cooperative predatory behavior in dinosaurs. When John Ostrom described Deinonychus antirrhopus in 1969 and 1970, he based much of his argument about pack hunting on the recurring spatial association of multiple Deinonychus teeth with Tenontosaurus carcasses in the Cloverly Formation. Ostrom inferred that groups of Deinonychus cooperatively attacked much larger Tenontosaurus individuals, similarly to the behavior of modern lions. This hypothesis became enormously influential and directly inspired the representation of Velociraptors as cooperative hunters in Jurassic Park (1993). However, subsequent analyses questioned the cooperative hunting interpretation. Roach and Brinkman (2007) argued that the association of Deinonychus with Tenontosaurus carcasses is more consistent with competitive scavenging behavior, like that observed in modern Komodo dragons feeding on the same carcass without true cooperation and frequently attacking each other during the feast. Evidence of multiple dead Deinonychus at the same localities as Tenontosaurus would suggest Tenontosaurus was capable of actively defending itself, killing some of its attackers. This debate about cooperative hunting versus competitive feeding in Deinonychus, centered on Tenontosaurus carcasses, remains without definitive resolution and continues to be one of the most stimulating problems in dinosaur behavior.

Cretaceous Herbivore 6.5m

MN · 76–69 Ma

Therizinosaurus

Therizinosaurus cheloniformis

"Reaping lizard with turtle-like form"

Therizinosaurus cheloniformis is one of the most bizarre dinosaurs ever discovered. It was a herbivorous theropod that lived during the Late Cretaceous, approximately 70 million years ago, in present-day Mongolia. Reaching up to 10 meters in length and weighing around 5 tonnes, its most striking feature was the enormous claws on its forelimbs, which could reach 70 cm in length, the largest of any known animal. Despite belonging to the same group as velociraptors and T. rex (Theropoda), Therizinosaurus was herbivorous, using its claws to pull down branches and feed on foliage. It was initially described as a giant turtle by Evgeny Maleev in 1954, and it took decades before paleontologists understood its true nature as a theropod dinosaur.

Cretaceous Herbivore 10m

US · 68–66 Ma

Torosaurus

Torosaurus latus

"Broad perforated lizard"

Torosaurus latus is one of the most imposing ceratopsids of the Late Cretaceous, notable for possessing the largest skull of any known land animal, reaching up to 2.77 meters in length. It lived between 68 and 66 million years ago in the Hell Creek and Lance Formations of western North America. Approximately 8 to 9 meters long and weighing up to 8 tonnes, it was a contemporary of Triceratops and Tyrannosaurus rex. Its extremely elongated frill bears two large bony openings (parietal fenestrae), a feature clearly distinguishing it from Triceratops. Described by Othniel Charles Marsh in 1891, Torosaurus sparked one of the most intense controversies in recent paleontology when Scannella and Horner (2010) proposed that its specimens were simply old Triceratops. Later studies, including bone histology analysis, refuted this hypothesis.

Cretaceous Herbivore 8.5m

US · 153–148 Ma

Torvosaurus

Torvosaurus tanneri

"Savage lizard of Tanner"

Torvosaurus tanneri is a large megalosaurid theropod from the Late Jurassic (late Kimmeridgian to basal Tithonian, about 153 to 148 million years ago) of the Morrison Formation of the western United States. Described by Peter Galton and James A. Jensen in 1979, it reached 9 to 10 metres in length, with some specimens estimated up to 11 metres, and 2 to 5 tonnes in body mass, ranking among the largest Jurassic carnivores worldwide. The skull was elongated, narrow and armed with ziphodont teeth up to 150 millimetres in crown height, among the largest ever recorded in non-avian theropods. Its forelimbs were short but extremely robust, with thick humerus and phalanges; the left humerus was designated lectotype by Britt in 1991. The animal occupied the apex predator role in the Morrison large-theropod guild alongside Allosaurus, Ceratosaurus and Saurophaganax. Later records extended the genus to Europe with the description of Torvosaurus gurneyi by Hendrickx and Mateus (2014) in the Lourinhã Formation of Portugal, and to embryos assigned to Torvosaurus sp. reported by Araújo and colleagues (2013), also from Portugal, among the oldest known dinosaur embryos.

Jurassic Carnivore 10m

US · 68–66 Ma

Triceratops

Triceratops horridus

"Horrible three-horned face"

Triceratops horridus is one of the most recognizable dinosaurs of the Late Cretáceous, famous for its three facial horns and large bony neck frill. It lived between 68 and 66 million years ago in the Lance and Hell Creek Formations of the western United States. Up to 9 meters long and weighing up to 12 tonnes, it was one of the largest herbivores in its ecosystem. The skull could exceed 2.5 meters in length, ranking among the largest of any terrestrial animal. Its dental battery included 36 to 40 tooth columns per jaw side, enabling processing of large volumes of fibrous plant material. The horns and frill were likely used primarily for species recognition, sexual display, and dominance among individuals, with possible secondary use in defense against Tyrannosaurus rex.

Cretaceous Herbivore 9m

US · 77–74 Ma

Troodon

Troodon formosus

"Wounding tooth (from Greek troodos = to wound + odon = tooth; formosus = beautiful in Latin)"

Troodon formosus was a small theropod from the Late Cretaceous of North America, notable for possessing the largest brain relative to body size among all known non-avian dinosaurs. At approximately 2.4 meters long and 45 kg, it inhabited the seasonal forests of the Two Medicine Formation in Montana. Its large, forward-facing eyes suggest binocular vision and possible nocturnal activity. Teeth with apical serrations indicate an omnivorous diet, including small mammals and possibly plant material. Originally described by Joseph Leidy in 1856 from a single tooth, Troodon became a symbol of the debate on intelligence and behavior in dinosaurs.

Cretaceous Omnivore 2.4m

CN · 77–73 Ma

Tsintaosaurus

Tsintaosaurus spinorhinus

"Tsingtao lizard with nasal spine"

Tsintaosaurus spinorhinus was a Campanian hadrosaurid from China, described by Yang Zhongjian in 1958 based on fossils collected at Laiyang, Shandong. Approximately 8.3 meters long and weighing 2.5 tonnes, it was a large herbivore that moved between bipedal and quadrupedal postures. Its most distinctive feature is the nasal crest: long described as a vertical unicorn-like spike, a 2013 analysis by Prieto-Márquez and Wagner revealed it to be the rear portion of a broader, lobate cranial structure formed by the nasal and premaxillary bones. The crest likely functioned in species recognition and acoustic communication within the herd.

Cretaceous Herbivore 8.3m

US · 68–66 Ma

T-Rex

Tyrannosaurus rex

"King of the tyrant lizards"

Tyrannosaurus rex is arguably the most famous dinosaur in the world. It lived at the end of the Cretáceous period, 68 to 66 million years ago, in what is now North America. At up to 12 meters long and over 8 metric tons, it was the apex predator of its ecosystem. Its serrated teeth measured up to 20 centimeters. While its tiny arms are often mocked, they were muscular enough to lift up to 200 kg. Recent research suggests T. rex may have had proto-feathers on parts of its body, as seen in close relatives.

Cretaceous Carnivore 12m

BR · 115–113 Ma

Ubirajara

Ubirajara jubatus

"Lord of the spear, with mane"

Ubirajara jubatus is a small coelurosaurian theropod from the Lower Cretaceous of the Araripe Basin, Ceará, discovered around 1990 and illegally exported to Germany in the 1990s. Described in 2020 by Smyth and colleagues as the first non-avian dinosaur from Gondwana with elaborate integumentary structures (a filamentous mane along the neck and two elongate, ribbon-like shoulder structures likely used for display), the animal became the epicentre of an international campaign for the repatriation of Brazilian fossils. The original paper was withdrawn in September 2021, and the name 'Ubirajara jubatus' was formally declared unavailable under the International Code of Zoological Nomenclature by Caetano, Delcourt and Ponciano (2023). Even so, the holotype SMNK PAL 29241 was repatriated to Brazil in June 2023 and now resides at the Plácido Cidade Nuvens Paleontology Museum of the Regional University of Cariri (URCA), in Santana do Cariri.

Cretaceous Carnivore 1m

BR · 228–225 Ma

Unaysaurus

Unaysaurus tolentinoi

"Black-water lizard (Tolentino)"

Unaysaurus tolentinoi is a small basal sauropodomorph from the Late Triassic (early Norian, around 225 million years ago) Caturrita Formation of the Paraná Basin in southern Brazil. About 2.5 m long and 70 kg, it is one of the most complete early sauropodomorphs known from South America, with a nearly intact skull and partially articulated postcranium. Leal and colleagues described holotype UFSM 11069 in 2004 and recovered it as a plateosaurid close to European Plateosaurus. In 2018 Müller, Langer and Dias-da-Silva erected the family Unaysauridae to accommodate Unaysaurus, Brazilian Macrocollum itaquii, and Indian Jaklapallisaurus asymmetricus, while Beccari et al. (2021) and Pretto et al. (2019) returned the taxon to the Plateosauridae orbit. The species is a global reference for studying the transition from small, opportunistic early sauropodomorphs to the large long-necked herbivores that would dominate the Jurassic.

Triassic Herbivore 2.5m

US · 126–125 Ma

Utahraptor

Utahraptor ostrommaysorum

"Utah thief of Ostrom and Mays"

Utahraptor ostrommaysorum is the largest known dromaeosaurid, the Early Cretáceous equivalent of a giant velociraptor. Up to 6 meters long and around 500 kg, it was considerably larger than Late Cretáceous dromaeosaurids. It lived 126 to 125 million years ago in the Cedar Mountain Formation of Utah, in an ecosystem dominated by large iguanodonts and ankylosaurs. Its most iconic feature is the retractable sickle claw on the second toe, up to 24 centimeters long, used to pin prey or inflict deep wounds. Like other dromaeosaurids, it was likely covered in feathers, inferred from close relatives with preserved feathers. A sandstone block containing at least seven individuals, including adults, juveniles, and a hatchling, suggests gregarious behavior with some social structure.

Cretaceous Carnivore 6m

AQ · 68–66.5 Ma

Vega Bird

Vegavis iaai

"Bird of Vega Island"

Vegavis iaai is a Late Cretaceous bird discovered on Vega Island, in the Antarctic Peninsula, and formally described by Julia Clarke and colleagues in 2005 in Nature. The fossil is considered the first indisputable evidence of a modern bird (crown-group Aves) preserved in the Mesozoic, around 68 to 66.5 million years old. Vegavis belongs to Anseriformes, the order that includes ducks, geese and swans, and held a phylogenetic position close to the family Anatidae. It was about the size of a modern duck or teal, with around 60 centimeters in length and an estimated mass of 1.5 kilograms. In 2016 a second specimen, also described by Clarke and team in Nature, revealed the first preserved syrinx (avian vocal organ) in the Mesozoic fossil record, proving that modern birds already vocalized before the Cretaceous-Paleogene mass extinction. Vegavis lived in an Antarctica still covered by forests, at high latitude but with a temperate to cold climate.

Cretaceous Omnivore 0.6m

MN · 75–71 Ma

Velociraptor

Velociraptor mongoliensis

"Swift thief of Mongolia"

Velociraptor mongoliensis was a small dromaeosaurid dinosaur approximately two meters long and under 20 kg, living during the late Campanian stage of the Cretáceous, 75 to 71 million years ago, in Mongolia. Unlike its depiction in Jurassic Park, it was roughly turkey-sized. It had confirmed feathers, evidenced by quill knobs on the ulna, a sickle-shaped enlarged claw on the second toe, and was likely an agile hunter of small vertebrates in the arid sand-dune environment of the Djadochta Formation.

Cretaceous Carnivore 2.07m

CN · 132–125 Ma

Wuerhosaurus

Wuerhosaurus homheni

"Wuerho lizard"

Wuerhosaurus homheni was a large stegosaurid from the Early Cretaceous of northwestern China, collected in the Wuerho (Urho) region of the Junggar Basin in the Xinjiang Uygur Autonomous Region. Roughly 7 meters long and an estimated 4 tonnes in weight, it occupies an unusual spot in stegosaur history: it lived between about 132 and 125 million years ago, tens of millions of years after the group's Late Jurassic peak. Most well-known stegosaurs, such as Stegosaurus, Kentrosaurus, Dacentrurus, and Miragaia, had vanished before the end of the Jurassic, making Wuerhosaurus one of the last well-documented representatives of the clade. The genus name refers directly to the town of Wuerho in the prefecture of Karamay, where the type material was collected, combined with the Greek suffix sauros, meaning lizard. The specific epithet homheni was coined by Dong Zhiming in the original publication. The holotype, catalogued as IVPP V4006, was collected in 1964 by a team from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) led by Dong Zhiming and described in 1973 in the volume Dinosaurs from Wuerho, published in the Memoirs of the IVPP. The material includes dorsal vertebrae, pelvic girdle, and fragments of dorsal plates; the skull was not preserved, which limits some fine anatomical comparisons. The specimen comes from the Tugulu Group, probably from the Lianmuqin Formation, a unit whose precise age is still debated but generally placed in the Early Cretaceous, somewhere between the Valanginian and Albian depending on the study. Wikipedia and regional surveys favor a Hauterivian to Barremian position, which we adopt here. The anatomy of Wuerhosaurus is marked by low, broad, rectangular dorsal plates, distinct from the famous tall triangular plates of Stegosaurus. This geometry changed the way paleontologists imagined the diversity of stegosaur armor and was one of the main reasons Dong erected a new genus. Robust femora, a wide pelvis, and vertebrae with low neural spines complete the profile of a heavy stegosaurid, adapted to slow quadrupedal locomotion. Like other stegosaurs, the animal likely carried a thagomizer, the set of terminal caudal spikes used in defense, though those elements were not recovered in the holotype. The systematic status of Wuerhosaurus has been debated. Maidment et al. (2008), in a broad cladistic review of Stegosauria, proposed that W. homheni was a junior synonym of Stegosaurus and should be renamed Stegosaurus homheni. The proposal was not universally accepted: most subsequent reviews, including Raven and Maidment (2017) and regional Chinese syntheses, continue to recognize Wuerhosaurus as a valid genus, given the distinctive combination of low rectangular plates and the survival of the clade into the Early Cretaceous. Dong also described, in 1993, a second species, Wuerhosaurus ordosensis, from the Ordos Basin in Inner Mongolia, which expanded the geographic range of the genus across Asia. Wuerhosaurus therefore remains a key piece for understanding how the stegosaur lineage survived beyond the Jurassic, before the clade's final extinction in the mid-Cretaceous.

Cretaceous Herbivore 7m

CN · 163–159 Ma

Yi

Yi qi

"Strange wings"

Yi qi (pronounced approximately 'ee chee') was a diminutive scansoriopterygid dinosaur that lived during the Middle to Late Jurassic, Oxfordian stage, approximately 163 to 159 million years ago, in the region of present-day Hebei, northern China. At only 0.6 meters in length with an estimated body mass of 380 grams, it was smaller than most modern pigeons. The most extraordinary feature of Yi qi is the styliform elongate bony rod projecting from the wrist: a long, pointed skeletal element that, together with a skin membrane (patagium), formed a wing of morphology entirely unlike any other known flying bird or dinosaur. This combination of a membrane wing supported by an accessory bony rod is unique among Dinosauria and finds functional parallels only in bats and flying squirrels among modern vertebrates. The holotype specimen (STM 31-2) was preserved with impressions of contour feathers on the body and filamentous plumage, plus portions of carbonized wing membrane visible around the forelimbs. Histological analysis of the feathers and bones indicates the animal had not reached full skeletal maturity at death, making adult size estimates slightly uncertain. Yi qi had long recurved foot claws consistent with arboreal habits, and simple conical teeth suggesting insectivorous or generalist carnivorous diet. The skull is relatively large in proportion to the body, with broad orbital openings, suggesting acute vision in a forest canopy environment. The phylogeny of Yi qi within Scansoriopterygidae is well-supported, but the placement of that clade within Coelurosauria remains debated: recent analyses alternate between positioning them as basal members of Pennaraptora or as an independent branch of theropods that developed gliding flight convergently and independently from modern birds. If Yi qi's patagium permitted active flight, it would represent a third independent origin of flight among feathered Jurassic dinosaurs, alongside the lineages leading to modern birds (Avialae) and possibly the gliding of Microraptor. Alternatively, aerodynamic analyses suggest the wing morphology was better suited to descending gliding from elevated perches than to sustained flapping. The discovery was announced in April 2015 in Nature by Xu Xing and collaborators, immediately becoming one of the most impactful paleontological finds of the decade.

Jurassic Carnivore 0.6m

CN · 125–122 Ma

Yutyrannus

Yutyrannus huali

"Beautiful feathered tyrant"

Yutyrannus huali is the largest feathered animal known in the history of life, measuring around 9 metres in length and weighing approximately 1.4 tonnes. It lived during the Early Cretaceous, some 125 million years ago, in what is now northeastern China. A basal tyrannosauroid of the family Proceratosauridae, it was a distant relative of the famous T. rex but far more primitive. Its filamentous feathers, exceptionally preserved in all three known specimens, reached up to 20 cm in length and covered much of the body, likely aiding thermoregulation in a cold, high-altitude environment. It bore a prominent nasal crest and proportionally longer arms than derived tyrannosaurids.

Cretaceous Carnivore 9m

US · 76–75 Ma

Zuul

Zuul crurivastator

"Zuul, destroyer of shins"

Zuul crurivastator is a large ankylosaurid from the Late Cretaceous (Campanian, about 76 million years ago) of the Coal Ridge Member of the Judith River Formation in Montana, United States. It was described in 2017 by Victoria M. Arbour and David C. Evans in Royal Society Open Science, based on holotype ROM 75860, housed at the Royal Ontario Museum in Toronto. The skeleton, initially exposed by chance in 2014 by a commercial team from Theropoda Expeditions LLC that was excavating a nearby tyrannosaur, turned out to be the most complete ankylosaurid ever found in North America: a whole skull, a complete tail with its terminal club, much of the postcranium, osteoderms preserved in situ, skin impressions, and even dark films interpreted as fossilised keratin sheaths of the spikes. The animal reached about six metres in length and weighed around 2.5 tonnes, with the typical low, broad ankylosaurid body, robust limbs, a neck guarded by cervical half rings of fused osteoderms, and a back covered by a complex carapace of polygonal plates, some forming pronounced lateral spikes over the flanks. The genus name Zuul, a nod to the Gatekeeper of Gozer in Ghostbusters (1984), was chosen because the short, rounded snout and two large backward-projecting squamosal horns immediately recall the film's demonic hound. The species epithet crurivastator, Latin for 'destroyer of shins', is a direct reference to the tail: the last seven caudal vertebrae are co-ossified into a rigid 'handle', and the tip ends in a huge bony club of fused osteoderms, heavy enough in theory to shatter the lower limbs of a large attacking theropod such as Daspletosaurus. Zuul also became a worldwide reference in a long-running debate in ankylosaur palaeontology: what was the tail club actually for? The holotype preserves, along its flanks near the pelvic girdle, osteoderms with pathologies (healed fractures, bone resorption) whose distribution is incompatible with predator bites but is consistent with lateral strikes delivered by another individual of the same species. In 2022, Arbour, Zanno and Evans presented this evidence in Biology Letters and concluded that the ankylosaurid tail club evolved largely as a weapon for intraspecific combat, probably tied to mate competition and sexual selection. Another extraordinary dimension of the holotype is the preservation of soft tissue: dark films over the osteoderms indicate keratin sheaths on the spikes, and there are scale impressions on the neck and tail. Together with Borealopelta markmitchelli (a nodosaurid preserved in three dimensions), Zuul is today the best material available to study what an ankylosaur's skin, armour and, in some cases, colouration may have looked like in life. It was also the first ankylosaurid described from the Judith River Formation, enriching the already famous portrait of Campanian Laramidia, which it shared with tyrannosaurids, ceratopsids and hadrosaurids on a warm, humid coastal plain on the western margin of the Western Interior Seaway.

Cretaceous Herbivore 6m

Mesozoic · Non-dinosaurs

Other Animals of the Mesozoic

Not dinosaurs, but they dominated the oceans, the skies, and parts of the continents during the same period.

BR · 112–108 Ma

Anhanguera

Anhanguera blittersdorffi

"Blittersdorff's evil spirit"

Anhanguera blittersdorffi is an anhanguerid pterosaur from the Lower Cretaceous of Brazil, described by Campos and Kellner in 1985 from an extraordinarily preserved three-dimensional skull. With an estimated wingspan of 4 to 4.5 meters, it was an aerial predator specialized in fish capture, bearing characteristic premaxillary crests, curved coniform teeth, and a rosette-shaped mandible. Originating from the calcareous nodules of the Romualdo Formation, Araripe Basin, in Ceará, it is one of the most studied Brazilian pterosaurs and an emblem of the Cretaceous fauna of northeastern Brazil.

Cretaceous Piscivore 4.5m

US · 100–72 Ma

Cretoxyrhina

Cretoxyrhina mantelli

"Mantell's sharp tooth from the Cretaceous"

Cretoxyrhina mantelli, popularly known as the Ginsu shark, was one of the largest and most feared marine predators of the Late Cretaceous. It lived approximately 100 to 72 million years ago in the Western Interior Seaway, a vast body of water that divided North America. Up to 6.5 meters long with anatomy similar to modern mako sharks, it preyed on mosasaurs, plesiosaurs, sea turtles, and pterosaurs. Several near-complete skeletons have been found in the Cretaceous of Kansas, making it one of the best-documented extinct sharks in science.

Cretaceous Carnivore 6.5m

DE · 157–137 Ma

Dakosaurus

Dakosaurus maximus

"Maximum biter lizard"

Dakosaurus maximus was the most fearsome marine crocodyliform of the Late Jurassic. Belonging to the family Metriorhynchidae, it stood apart from all other members of the group by possessing laterally compressed, serrated teeth convergent with those of terrestrial theropods, indicating specialization in large prey. Without osteoderm armor and with limbs transformed into flippers and a lunate bifurcated tail, it was fully adapted to pelagic life. Its fossils were found in Europe (France, Germany, Switzerland, Poland, England) and Argentina, where the D. andiniensis specimen was nicknamed 'Godzilla' by Argentine paleontologists. It was the apex predator of the European Jurassic seas.

Jurassic Carnivore 4.5m

US · 82–73 Ma

Terror Croc

Deinosuchus riograndensis

"Terrible Rio Grande crocodile"

Deinosuchus riograndensis was one of the largest crocodilians ever to live, reaching about 10 to 12 meters in length and 3,500 to 8,500 kg. Placed in the superfamily Alligatoroidea according to the revision of Cossette and Brochu (2020), it inhabited the coastal plains and estuaries of the Western Interior Seaway during the Campanian, around 82 to 73 million years ago. Its name means, terrible crocodile of the Rio Grande, after the river that bounds Big Bend National Park, Texas, where the most complete specimens were collected. It had banana-sized teeth, thick dorsal osteoderms and a bite force comparable to that of Tyrannosaurus rex, preying on hadrosaurs, ceratopsians and marine turtles. A recent phylogenetic analysis by Walter et al. (2025) proposed repositioning the genus as a stem-crocodylian outside Alligatoroidea.

Cretaceous Carnivore 11m

US · 80.5–77 Ma

Elasmosaurus

Elasmosaurus platyurus

"Thin-plate flat-tailed reptile"

Elasmosaurus platyurus was one of the largest and most distinctive plesiosaurs of the Late Cretaceous, famous for its extraordinarily long neck that accounted for more than half of its total length of approximately 14 meters. With 71 cervical vertebrae, it holds the record for the greatest number of neck vertebrae of any known vertebrate. It was not a dinosaur but a marine reptile of the group Sauropterygia. It lived in the Western Interior Seaway that covered central North America, feeding on fish and cephalopods with sharp teeth. It became famous for a historic error: when Edward Drinker Cope described it in 1868, he assembled the skeleton with the skull at the wrong end, placing it at the tip of the tail. The mistake was corrected in 1870 following the intervention of Joseph Leidy.

Cretaceous Piscivore 14m

DE · 183–174 Ma

Hybodus

Hybodus hauffianus

"Hauff's humped shark"

Hybodus hauffianus is one of the best-documented extinct sharks of the Mesozoic. It lived in the Early Jurassic, approximately 183 to 174 million years ago, in the shallow warm seas that covered central Europe. Up to 2 meters long, it had two types of teeth: pointed at the front for catching slippery prey and flattened toward the back for crushing hard-shelled prey. Exceptional specimens preserved in the Posidonia Shale of Germany reveal rare anatomical details, including stomach contents with belemnite rostra, confirming its diet of cephalopods.

Jurassic Carnivore 2m

AU · 115–100 Ma

Kronosaurus

Kronosaurus queenslandicus

"Kronos lizard from Queensland"

Kronosaurus queenslandicus was one of the largest pliosaurids of the Early Cretaceous, with an estimated length of 9 to 11 meters and a skull 2.2 meters long, one of the largest of any prehistoric reptile. It was not a dinosaur but a marine reptile of the clade Pliosauridae. It lived in the Eromanga Sea that covered inland Australia during the Aptian-Albian (~115-100 Ma). The nickname 'Plasterosaurus' reflects the controversial Harvard reconstruction (MCZ 1285), where eight extra plaster vertebrae were added to the specimen, inflating the length from 10.5 to 12.8 meters. With conical teeth up to 7 centimeters, it was the dominant apex predator of its environment, capable of attacking plesiosaurs, sea turtles, and large fish.

Cretaceous Carnivore 10.5m

FR · 166–155 Ma

Liopleurodon

Liopleurodon ferox

"Smooth-sided teeth, fierce"

Liopleurodon ferox was a pliosaur, a predatory marine reptile from the Middle to Late Jurassic seas that covered Europe around 166 to 155 million years ago. It was not a dinosaur: it belongs to Sauropterygia, a fully aquatic lineage with four paddle-shaped flippers, a short neck, and an elongated skull. Recent studies estimate a typical body length between 5 and 7 meters, far from the 25 meters depicted in the BBC documentary Walking with Dinosaurs (1999). The name means 'smooth-sided teeth', referring to the enamel ridges on the tooth crown. It was an apex predator of the epicontinental seas, feeding on fish, cephalopods, and other marine reptiles, as shown by preserved stomach contents. The holotype, described by Henri Sauvage in 1873, is a single tooth from the Boulogne-sur-Mer region of France; the species' identity has been progressively refined through decades of taxonomic work.

Jurassic Piscivore 6.5m

ZA · 252–249 Ma

Lystrosaurus

Lystrosaurus murrayi

"Murray's shovel lizard"

Lystrosaurus murrayi is a dicynodont (non-mammalian synapsid) that survived the greatest mass extinction in the history of life, the end-Permian catastrophe approximately 252 million years ago. In the Early Triassic it constituted more than 90% of terrestrial vertebrates, a dominance unparalleled in tetrapod history. Its massive skull bore a horny beak for cutting vegetation and two small upper tusks. Roughly the size of a medium pig, Lystrosaurus murrayi has become a symbol of post-extinction resilience and continental drift, with fossils found in South Africa, Antarctica, India, China, and Russia.

Triassic Herbivore 0.9m

NL · 82–66 Ma

Mosasaurus

Mosasaurus hoffmannii

"Hoffmann's Meuse River lizard"

Mosasaurus hoffmannii was the largest known mosasaur and one of the greatest marine predators of all time. At up to 13 meters long (recent estimates revised from earlier 17-meter values) and an estimated weight of 10 tonnes, it dominated the oceans of the Late Cretaceous. It was not a dinosaur but a squamate reptile (Squamata), closely related to monitor lizards and snakes. It possessed a double-hinged jaw similar to snakes, allowing it to swallow large prey. Its robust, conical teeth were adapted for a generalist diet: fish, sharks, cephalopods, sea turtles, seabirds, and other mosasaurs. The first Mosasaurus fossil, found in Maastricht (Netherlands) in 1764, was one of the first giant marine reptiles described by science, even before Darwin. The holotype skull was confiscated by French soldiers during the Siege of Maastricht in 1794 and taken to Paris, where Georges Cuvier used it as evidence that species could go extinct, a revolutionary concept at the time.

Cretaceous Carnivore 13m

GB · 165–150 Ma

Ophthalmosaurus

Ophthalmosaurus icenicus

"Eye lizard (from Greek: ophthalmos = eye, sauros = lizard)"

Ophthalmosaurus icenicus was a Middle-Late Jurassic ichthyosaur, famous for having the largest eyes relative to body size of any known vertebrate: the sclerotic ring measured up to 23 centimeters in outer diameter. Found primarily in the Oxford Clay Formation of Peterborough, England, it was an agile oceanic swimmer with a hydrodynamic body of about 6 meters and paddle-shaped fins. Although not a dinosaur, it was strictly contemporary with many of them. Its enormous eyes were adapted for deep dives in dark mesopelagic zones, likely in pursuit of squid and cephalopods. Harry Govier Seeley described the species in 1874, and since then it has become one of the best-documented ichthyosaurs of the Jurassic, with dozens of excellent preserved specimens.

Jurassic Piscivore 6m

US · 228–201 Ma

Postosuchus

Postosuchus kirkpatricki

"Crocodile from Post (Post, Texas)"

Postosuchus kirkpatricki was one of the largest terrestrial predators of the Late Triassic in North America. A crurotarsal archosaur belonging to the family Rauisuchidae, it was not a dinosaur but rather a distant relative of modern crocodilians. Estimated at 4 to 6 meters in length, it had an erect posture, laterally compressed serrated teeth, and a robust skull. Locomotion was predominantly bipedal in adults, with the forelimbs progressively reduced with growth. It lived in the tropical humid and semiarid environments of the Late Triassic, coexisting with the first dinosaurs and the rhynchosaurs it would eventually replace.

Triassic Carnivore 5m

US · 88–80 Ma

Pteranodon

Pteranodon longiceps

"Toothless wing with long head"

Pteranodon longiceps is the most studied pterosaur in the history of paleontology, with over 1,200 known specimens. It flew over the Western Interior Seaway, a shallow waterway that covered the center of North America in the Cretaceous. Adult males reached wingspans of 5.6 to 7.6 meters, while females were smaller, at approximately 3.8 meters. The long backward-pointing head crest was more prominent in males. Despite its imposing appearance, it was a specialized piscivore, capturing fish at the sea surface with its long, toothless beak.

Cretaceous Piscivore 1.8m

US · 68–66 Ma

Quetzalcoatlus

Quetzalcoatlus northropi

"Feathered serpent of Northrop"

Quetzalcoatlus northropi is the largest known pterosaur and one of the largest flying animals in Earth's history. With a wingspan estimated at 10 to 11 meters, it was as wide as a single-engine aircraft. It lived during the late Maastrichtian, 68 to 66 million years ago, in the Javelina Formation of Texas, in the basin of what is now Big Bend National Park. Despite its colossal size, it weighed only 150 to 250 kg thanks to hollow bones reinforced with internal struts. Biomechanical studies show it was capable of active flight, taking off with a quadrupedal vault using its forelimbs. On land, it walked quadrupedally and hunted small vertebrates in the manner of a giant stork.

Cretaceous Carnivore 5m

CN · 125–123 Ma

Repenomamus

Repenomamus robustus

"Robust reptile mammal"

Repenomamus robustus was one of the largest Mesozoic mammals and living proof that mammals of the Age of Dinosaurs were not all small and harmless. Belonging to the order Eutriconodonta and family Gobiconodontidae, it lived during the Aptian of the Early Cretaceous in Liaoning, China, in the same fauna as Microraptor gui. At approximately 50 cm in body length and an estimated weight of 4.5 kg, it was as large as a modern Virginia opossum. The most notable find is a specimen with bones of a juvenile Psittacosaurus fossilized in the stomach, the only direct evidence of a Mesozoic mammal preying on dinosaurs. The robust mandible and heterodont teeth confirm frankly carnivorous habits.

Cretaceous Carnivore 0.5m

GB · 183–178 Ma

Rhomaleosaurus

Rhomaleosaurus cramptoni

"Crampton's robust lizard"

Rhomaleosaurus cramptoni was a basal pliosauroid of the Early Jurassic, about 7 meters long with a skull roughly 88 centimeters in length. It was not a dinosaur but a marine reptile of the family Rhomaleosauridae, the dominant predatory group of early Jurassic seas. The type skeleton, now in the National Museum of Ireland – Natural History in Dublin, was unearthed in 1848 by alum quarry workers at Kettleness, Yorkshire coast, England. Carte and Baily described it in 1863 as Plesiosaurus cramptoni; Harry Seeley reclassified it in 1874, erecting the genus Rhomaleosaurus. The animal combined the relatively hydrodynamic body of a plesiosaur with the large head and robust jaws of a pliosaur, occupying the niche of a versatile mid-sized apex predator.

Jurassic Piscivore 7m

NE · 133–112 Ma

SuperCroc

Sarcosuchus imperator

"Emperor flesh crocodile"

Sarcosuchus imperator was a giant crocodyliform of the family Pholidosauridae that inhabited rivers and humid plains of subcontinental Africa during the Aptian-Albian, around 133 to 112 million years ago. The nearly complete specimen collected in 1964 at Gadoufaoua, in present-day Niger, and formally described by de Broin and Taquet in 1966 provided the first skull of more than one and a half meters of the genus. Sereno and colleagues, in 2001, estimated that adults reached 11 to 12 meters in length and 8 tonnes based on cranial allometry, figures later revised downward by O'Brien and colleagues in 2019, who proposed about 9.5 meters and 4,300 kilos from a phylogenetically informed regression of head width. The name combines the Greek words for flesh, crocodile and emperor, reflecting the exceptional size. It had a wide, robust snout, conical non-interlocking teeth, thick dorsal osteoderms and a hollow bone structure at the tip of the snout called a bulla, present in all adult specimens and still of no clearly established function.

Cretaceous Carnivore 9.5m

US · 221–205 Ma

Smilosuchus

Smilosuchus gregorii

"Gregory's knife-crocodile (honoring geologist Herbert E. Gregory)"

Smilosuchus gregorii was one of the largest semiaquatic predators of the Late Triassic of North America. Up to 6 meters long, it occupied the same ecological niche as modern crocodiles: ambush predation along the margins of rivers and lakes in the Chinle Formation of what is now Arizona. Its key distinction from true crocodilians lies in nostril position: instead of opening at the tip of the snout, phytosaur nostrils open in a bony mound between the eyes. The skull of S. gregorii can exceed 1.5 meters in length, with heterodontic dentition, large anterior tusks for impaling prey and more blade-like posterior teeth for slicing flesh. The species was originally described by Camp (1930) and transferred to the genus Smilosuchus by Long and Murry (1995).

Triassic Carnivore 6m

US · 100–72 Ma

Squalicorax

Squalicorax falcatus

"Falcate crow shark (from the curved, sickle-like teeth)"

Squalicorax falcatus was a medium-sized lamniform shark that inhabited the shallow seas of the Late Cretaceous, including the extensive Western Interior Seaway of North America. About 2.5 meters in length, it had a fusiform body similar to the modern reef shark, but its strongly serrated teeth resembled those of today's tiger shark. The genus Squalicorax, commonly called the crow shark, was a generalist predator and opportunistic scavenger. Fossil evidence includes teeth embedded in bones of terrestrial hadrosaurs, mosasaurs, and sea turtles, revealing that it fed on carcasses washed into the sea. The species S. falcatus is known from nearly complete skeletons found in Kansas, making it one of the best-documented Mesozoic sharks.

Cretaceous Carnivore 2.5m