Mylodon is a genus of extinct ground sloth belonging to the family Mylodontidae, known from southern South America. With a total length of 3 to 4 m and a body mass of 1-2 tonnes, it is one of the largest mylodontids.
Alvarezsauridae is a family of small, long-legged dinosaurs. Although originally thought to represent the earliest known flightless birds, they are now thought to be an early diverging branch of maniraptoran theropods. Alvarezsaurids were highly specialized. They had tiny but stout forelimbs, with compact, bird-like hands. Their skeletons suggest that they had massive breast and arm muscles, possibly adapted for digging or tearing. They had long, tube-shaped snouts filled with tiny teeth. They have been interpreted as myrmecophagous, adapted to prey on colonial insects such as termites, with the short arms acting as effective digging instruments to break into nests.
Proceratosaurus is a genus of carnivorous theropod dinosaur from the Middle Jurassic (Bathonian) of England. It contains a single species. P. bradleyi, known from a mostly complete skull and lower jaws. Proceratosaurus was a small dinosaur, estimated to measure around 3 m (9.8 ft) in length. Its name refers to how it was originally thought to be an ancestor of Ceratosaurus, due to the partially preserved portion of the crest of Proceratosaurus superficially resembling the small crest of Ceratosaurus. Now, however, it is considered a coelurosaur, specifically a member of the family Proceratosauridae, and amongst the earliest known members of the clade Tyrannosauroidea.
Amargasaurus is a genus of sauropod dinosaur from the Early Cretaceous epoch of what is now Argentina. The only known skeleton was discovered in 1984 and is virtually complete, including a fragmentary skull, making Amargasaurus one of the best-known sauropods of its epoch. Amargasaurus was first described in 1991 and contains a single known species, Amargasaurus cazaui. It was a large animal, but small for a sauropod, reaching 9 to 13 meters in length. Most distinctively, it sported two parallel rows of tall spines down its neck and back, taller than in any other known sauropod. In life, these spines could have stuck out of the body as solitary structures that supported a keratinous sheath. An alternate hypothesis, now more favored, postulates that they could have formed a scaffold supporting a skin sail. They might have been used for display, combat, or defense.
Prosqualodon is an extinct genus of Early to Middle Miocene cetacean from Argentina, Australia, New Zealand and Venezuela.
Protypotherium is an extinct genus of notoungulate mammals native to South America during the Oligocene and Miocene epochs. A number of closely related animals date back further, to the Eocene. Fossils of Protypotherium have been found in the Deseadan Fray Bentos Formation of Uruguay, Muyu Huasi and Nazareno Formations of Bolivia, Cura-Mallín and Río Frías Formations of Chile, and Santa Cruz, Salicas, Ituzaingó, Aisol, Cerro Azul, Cerro Bandera, Cerro Boleadoras, Chichinales, Sarmiento and Collón Curá Formations of Argentina.
Notosuchus is an extinct genus of South American notosuchian crocodyliforms. It was terrestrial, living approximately 85 million years ago in the Santonian stage of the Late Cretaceous.
Proterochampsa is an extinct genus of proterochampsid archosauriform from the Late Triassic of South America. The genus is the namesake of the family Proterochampsidae, and the broader clade Proterochampsia. Like other proterochampsids, Proterochampsa are quadruped tetrapods superficially similar in appearance to modern crocodiles, although the two groups are not closely related. Proterochampsids can be distinguished from other related archosauriformes by characters such as a dorsoventrally flattened, triangular skull with a long, narrow snout at the anterior end and that expands transversally at the posterior end, asymmetric feet, and a lack of postfrontal bones in the skull, with the nares located near the midline. Proterochampsa is additionally defined by characters of dermal sculpturing consisting of nodular protuberances on the skull, antorbital fenestrae facing dorsally, and a restricted antorbital fossa on the maxilla. The genus comprises two known species: Proterochampsa barrionuevoi and Proterochampsa nodosa. P. barrionuevoi specimens have been discovered in the Ischigualasto Formation in northwestern Argentina, while P. nodosa specimens have been found in the Santa Maria supersequence in southeastern Brazil. The two species are distinct in several characters, including that P. nodosa has larger, more well-developed nodular protuberances, a more gradually narrowing snout, and a higher occiput than P. barrionuevoi. Of the two, P. nodosa is thought to have less derived features than P. barrionuevoi.
Notobatrachus is an extinct genus of frog from the Lower Jurassic (Toarcian) Cañadon Asfalto Formation, Cañadón Asfalto Basin and Middle Jurassic La Matilde Formation, Deseado Massif of Patagonia, Argentina. N. degiustoi is the most completely known Jurassic frog and has been recorded in many outcrops of the La Matilde Formation of the Deseado Massif in southern Patagonia.
Ilchunaia is an extinct genus of sebecid mesoeucrocodylian. Fossils have been found from the Divisadero Largo Formation of Argentina dating back to the Late Eocene, and a locality in Mendoza, Argentina dating back to the Oligocene. Little material is known from the genus, with only the anterior portion of the skull being present to study.
Condorchelys was a genus of stem turtle from Early Jurassic Cañadon Asfalto Formation of Argentina. Condorchelys represents the oldest Jurassic-aged Turtle from South America, with only one species described, Condorchelys antiqua.
Pipoidea are a clade of frogs, that contains the most recent common ancestor of living Pipidae and Rhinophrynidae as well as all its descendants. It is broadly equivalent to Xenoanura.
Manidens is an extinct genus of heterodontosaurid dinosaur from the Early Jurassic of Patagonia. It is a sister taxon of the closely related Pegomastax from South Africa. Fossils have been found in the Cañadón Asfalto Formation in Chubut Province, Argentina, considered to be originally dated to the Bajocian, latter were found to be from Toarcian beds.
Proborhyaenidae is an extinct family of metatherian mammals of the order Sparassodonta, which lived in South America from the Eocene (Mustersan) until the Oligocene (Deseadan). Sometimes it has been included as a subfamily of their relatives, the borhyaenids. The largest species, Proborhyaena gigantea, is estimated to be about the size of a spectacled bear, with its skull reaching 60 cm (2.0 ft) in length, and body mass estimates up to approximately 90–200 kg (200–440 lb), making the proborhyaenids some of the largest known metatherians. Proborhyaenid remains have been found in western Bolivia, Uruguay, southern Brazil, and the provinces of Mendoza, Salta, and Chubut, in Argentina.
Necrolestes is an extinct genus of mammals, which lived during the Early Miocene in what is now Argentine Patagonia. It is the most recent known genus of Meridiolestida, an extinct group of mammals more closely related to therians than to monotremes, which were the dominant mammals in South America during the Late Cretaceous. It contains two species, N. patagonensis and N. mirabilis; the type species N. patagonensis was named by Florentino Ameghino in 1891 based on remains found by his brother, Carlos Ameghino in Patagonia. Fossils of Necrolestes have been found in the Sarmiento and Santa Cruz Formations. Its morphology suggests that it was a digging, subterranean-dwelling mole-like mammal that fed on invertebrates.
Astraponotus is an extinct genus of astrapotheriids. It lived during the Middle-Late Eocene and its fossil remains have been found in the Sarmiento Formation of Argentina, South America.
Xesmodon is an extinct genus of mammal. It lived from the Middle to the Late Eocene, in what is today South America.
Eucinepeltus is an extinct genus of glyptodont. It lived during the Early Miocene, and its fossilized remains were discovered in South America.
The Sarmiento Formation, in older literature described as the Casamayor Formation, is a geological formation in Chubut Province, Argentina, in central Patagonia, which spans around 30 million years from the mid-Eocene to the early Miocene. It predominantly consists of pyroclastic deposits, which were deposited in a semi-arid environment. It is divided up into a number of members. The diverse fauna of the Sarmiento Formation, including a variety of birds, crocodilians, turtles and snakes, also includes many mammals such as South American native ungulates as well as armadillos, and caviomorph rodents.
The Cañadón Asfalto Formation is a geological formation which dates to the Toarcian age of the Early Jurassic period of Argentina. The rocks of the formation preserve a diverse biota, including plants, dinosaurs, invertebrates, mammals and pterosaurs, among others. The formation is divided into two members: the lower Las Chacritas Member, and the overlying Puesto Almada member, though the latter has also been assigned to the overlying Cañadón Calcáreo Formation by some authors. The members are typically composed of fluvial-lacustrine deposits consisting of sandstones and shales, with a limestone carbonate evaporitic sequence also being present in the lower of the two.
