''Trialestes'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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

(

Carnian The Carnian (less commonly, Karnian) is the lowermost stage (stratigraphy), stage of the Upper Triassic series (stratigraphy), Series (or earliest age (geology), age of the Late Triassic Epoch (reference date), Epoch). It lasted from 237 to 227.3 ...

)

crocodylomorphs Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably more ...

that lived in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. It has been classified as a

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

in the past due it being adapted as a terrestrial, running carnivore. It is classified in

Sphenosuchia Sphenosuchia is a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Middle Jurassic. Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral to crocodyliforms ...

, which were early relatives of

crocodylia Crocodilia () is an Order (biology), order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorp ...

ns. Irmis, Nesbitt and Sues (2013) noted that some of the material referred to this taxon is actually dinosaurian; however, according to the authors, the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen PVL 2561, found in the Cancha de Bochas Member of the

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

in the Ischigualasto-Villa Unión Basin in northwestern Argentina, "comprises a single individual that preserves unambiguous crocodylomorph synapomorphies", indicating it is indeed a crocodylomorph, and one of the referred specimens, PVL 3889, does share one or more autapomorphies with the holotype, indicating it represents the same taxon. The type species, ''T. romeri'', was named in 1963.O. A. Reig. 1963. La presencia de dinosaurios saurisquios en los "Estratos de Ischigualasto" (Mesotriasico Superior) de las provincias de San Juan y La Rioja (República Argentina) he presence of saurischian dinosaurs in the "Ischigualasto beds" (upper Middle Triassic) of San Juan and La Rioja Provinces (Argentine Republic) Ameghiniana 3(1):3-20

References

External links

Trialestidae
at Palaeos

{{Portal bar, Paleontology Terrestrial crocodylomorphs Triassic crocodylomorpha Carnian genera Late Triassic reptiles of South America Triassic Argentina Fossils of Argentina Ischigualasto Formation Fossil taxa described in 1982 Taxa named by José Bonaparte Prehistoric pseudosuchian genera