Regional hub

Dinosaurs from Patagonia and Argentina

Argentina is the paleontological powerhouse of the Southern Hemisphere, with fossils spanning the entire Mesozoic in formations distributed from the northwest to Patagonia. The Ischigualasto Formation in San Juan Province (Late Triassic, ~231 Ma) preserves the world's earliest known dinosaurs, including Herrerasaurus ischigualastensis, Eoraptor lunensis, Gnathovorax cabreirai, and the first sauropodomorphs. The Cañadón Asfalto Formation, from the Middle Jurassic of Chubut, records the transition to ecosystems dominated by dinosaurs. In the Late Cretaceous, the Candeleros and Huincul Formations of the Neuquén Basin produced the largest known theropods: Giganotosaurus carolinii, Mapusaurus roseae, and the megaraptorid Megaraptor namunhuaiquii. The La Colonia Formation preserved the iconic abelisaurid Carnotaurus sastrei. Titanosaur sauropods reached colossal sizes in the Patagonian formations Cerro Barcino, Cerro Lisandro, and Lago Colhué Huapí: Argentinosaurus huinculensis, Patagotitan mayorum, and Dreadnoughtus schrani rank among the largest land animals that ever existed.

15 species in the catalog

3 Triassic

1 Jurassic

11 Cretaceous

Filter by: 15 species

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

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

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

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

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

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

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

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

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

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

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

AR · 83–80 Ma

Abelisaurus

Abelisaurus comahuensis

"Abel's lizard from the Comahue region"

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

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

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

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