''Pseudhesperosuchus'' (meaning "false ''

Hesperosuchus ''Hesperosuchus'' is an extinct genus of crocodylomorph reptile that contains a single species, ''Hesperosuchus agilis''. Remains of this pseudosuchian have been found in Late Triassic (Carnian) strata from Arizona and New Mexico.Colbert, E. H. 1 ...

''") is a

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 ...

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 ...

n, a type of basal

crocodylomorph 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 mor ...

, the

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

that comprises the

crocodilia Crocodilia () is an 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 crocodylomorph pseudosuchia ...

ns and their closest kin. It is known from a partial skeleton and skull found in rocks of the

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 ...

(

Norian The Norian is a division of the Triassic geological period, Period. It has the rank of an age (geology), age (geochronology) or stage (stratigraphy), stage (chronostratigraphy). It lasted from ~227.3 to Mya (unit), million years ago. It was prec ...

-age)

Los Colorados Formation The Los Colorados Formation is a sedimentary geological formation, rock formation of the Ischigualasto-Villa Unión Basin, found in the provinces of San Juan Province, Argentina, San Juan and La Rioja Province (Argentina), La Rioja in Argentina. ...

of the

Ischigualasto-Villa Unión Basin The Ischigualasto-Villa Unión Basin () is a small sedimentary basin located in the Argentine Northwest, Argentina. It is located in the southwestern part of La Rioja Province and the northeastern part of San Juan Province. The basin borders the ...

in northwestern

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

History and description

''Pseudhesperosuchus'' is based on PVL 3830. This specimen consists of a skull and lower jaws, most of the

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

l column, the

shoulder girdle The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans, it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists o ...

, and parts of the arms and legs. The genus was named by

José Bonaparte José Fernando Bonaparte (14 June 1928–18 February 2020) was an Argentine paleontologist who discovered a plethora of South American dinosaurs and mentored a new generation of Argentine paleontologists. He has been described by paleontologist ...

in 1969. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is ''P. jachaleri''. The skull, though nearly complete, is poorly preserved, and some of its bones and sutures have been misidentified over the years. A 2002

phylogenetic analysis In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data ...

of sphenosuchians performed by James Clark and Hans–Dieter Sues found ''Pseudhesperosuchus'' to have an unresolved position along with several other sphenosuchians, neither closer to true crocodiles or to ''

Sphenosuchus ''Sphenosuchus'' ("wedge crocodile") is an extinct genus of crocodylomorph from the Early Jurassic Elliot Formation of South Africa, discovered and described early in the 20th century. The skull is preserved very well but other than elements of t ...

''. The genus is sometimes misspelled ''Pseudohesperosuchus'', as in Carroll (1988).

References

{{Portal bar, Paleontology Triassic crocodylomorpha Terrestrial crocodylomorphs Norian life Late Triassic reptiles of South America Triassic Argentina Fossils of Argentina Los Colorados Formation Fossil taxa described in 1969 Taxa named by José Bonaparte Prehistoric pseudosuchian genera