''Ischigualastia'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of large

dicynodont Dicynodontia is an extinct clade of anomodonts, an extinct type of non-mammalian therapsid. Dicynodonts were herbivorous animals with a pair of tusks, hence their name, which means 'two dog tooth'. Members of the group possessed a horny, typic ...

therapsid Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more ...

s that lived during the Late Carnian age and the Early Norian age of the

Late Triassic The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. ...

Period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

. The genus was found in and named after the

Ischigualasto Formation The Ischigualasto Formation is a Late Triassic fossiliferous formation and Lagerstätte in the Ischigualasto-Villa Unión Basin of the southwestern La Rioja Province and northeastern San Juan Province in northwestern Argentina. The formation ...

(Cancha de Bochas Member) of the Ischigualasto-Villa Unión Basin in northwestern

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

. It has been placed in the family

Stahleckeriidae Stahleckeriidae is a family of dicynodont therapsids whose fossils are known from the Triassic of North America, South America, Asia and Africa. Classification Phylogeny Below is a cladogram A cladogram (from Greek ''clados'' "branch" and ...

Description

The genus is described as an enormous dicynodont, with a short, high skull, and lacking tusks. It is regarded as larger than its later, more famous relative ''

Placerias ''Placerias'' (meaning 'broad body') is an extinct genus of dicynodonts that lived during the Carnian to the Norian age of the Triassic Period (230–220 million years ago). ''Placerias'' belongs to a group of dicynodonts called Kannemeyeriifor ...

'', which weighed over .

Paleoecology

It was a large

quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...

al herbivore, most common at the base of the

. It was a common member of the local fauna, although not as abundant as the medium-sized herbivores ''

Hyperodapedon ''Hyperodapedon'' is a genus of rhynchosaurs (beaked, archosaur-like reptiles) from the Late Triassic period (Carnian stage). Fossils of the genus have been found in Africa, Asia, Europe and North and South America. Its first discovery and namin ...

'' and ''

Exaeretodon ''Exaeretodon'' is an extinct genus of fairly large, low-slung traversodontid cynodonts from the southern parts of Pangea. Four species are known, from various formations. ''E. argentinus'' is from the Carnian-age (Late Triassic) Cancha de Boch ...

''. The only danger to such a huge animal was the almost equally large carnivorous pseudosuchian ''

Saurosuchus ''Saurosuchus'' (meaning "lizard crocodile") is an extinct genus of large loricatan pseudosuchian archosaur that lived in South America during the Late Triassic period. It was a heavy, ground-dwelling, quadrupedal carnivore, likely being the ape ...

'' and perhaps the predatory dinosaur ''

Herrerasaurus ''Herrerasaurus'' is a genus of saurischian dinosaur from the Late Triassic period. This genus was one of the earliest dinosaurs from the fossil record. Its name means "Herrera's lizard", after the rancher who discovered the first specimen in ...

'', which shared the same environment. It is likely that pressure from this predator pushed ''Ischigualastia'' into extinction, for it becomes less common and finally disappears in the higher levels of the Ischigualasto Formation. A somewhat relative, ''

'', survived in Laurasia.

Gallery

File:Ischigualastia.jpg, Life restoration of ''I. jenseni'' File:Ischigualastia scale.svg, Size of ''I. jenseni'' relative to a human

References

External links

* Dicynodonts Carnian genera Late Triassic synapsids of South America Triassic Argentina Fossils of Argentina Fossil taxa described in 1962 Anomodont genera {{anomodont-stub

Description

Paleoecology

Gallery

See also

References

External links