''Vjushkovisaurus'' 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 ...

of Middle Triassic archosauriform. It is known from the

Anisian In the geologic timescale, the Anisian is the lower stage (stratigraphy), stage or earliest geologic age, age of the Middle Triassic series (stratigraphy), series or geologic epoch, epoch and lasted from million years ago until million years ag ...

-aged Donguz Gorizont in Sol-Iletsk, Orenburg Oblast,

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. The genus was named in 1982, with 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 ...

being ''V. berdjanensis''. Material has been collected in the Berdyanka II locality from a fossil assemblage called the '' Eryosuchus'' Fauna along the Berdyanka River, specifically in a

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

carbonate A carbonate is a salt of carbonic acid, (), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate group ...

concretion in the upper part of the main river channel. ''Vjushkovisaurus'' is known only from the holotype PIN 2865/62 (formerly SGU 104/3871), a partial postcranial skeleton which consists of 12 presacral

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 ...

e, left humerus, ribs, a fragment of the coracoid and a fragment of the fibula.

Description

Most rauisuchids have a crest on the ilium called the supra- acetabular process that overlies the head of the

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

, allowing them to have a "pillar-erect" stance. As an early rauisuchid ''Vjushkovisaurus'' lacks this crest, but it does have a small thickening on the surface of the ilium. The humerus differs from other better known rauisuchids in that it is shorter and broader. However, it has been suggested that the only known humerus of ''Vjushkovisaurus'' may actually belong to an

aetosaur Aetosaurs () are heavily armored reptiles belonging to the extinct order (biology), order Aetosauria (; from Ancient Greek, Greek, (aetos, "eagle") and (, "lizard")). They were medium- to large-sized Omnivore, omnivorous or Herbivore, herbivor ...

. More recently, Nesbitt (2009) argued that ''Vjushkovisaurus'' represent most probably a valid non- archosaurian archosauriform. According to his analysis, the original diagnosis of ''Vjushkovisaurus'' by Ochev (1982) consisted of some of the plesiomorphies for Archosauriformes and characters with wide distributions throughout archosauriforms. For example, elongated anterior cervical vertebrae are present in the poposauroids, '' Yarasuchus'', and in the non-archosaurian archosauriforms '' Proterosuchus'' and '' Guchengosuchus''. Other features which are typically thought to be associated with

skeletal pneumaticity Skeletal pneumaticity is the presence of air spaces within bones. It is generally produced during development by excavation of bone by pneumatic diverticula (air sacs) from an air-filled space, such as the lungs or nasal cavity. Pneumatization is h ...

, are also present in ''Guchengosuchus'', '' Erythrosuchus'', and in several archosaurs. Additionally, the shape and placement of the deltopectoral crests of the humerus of ''Vjushkovisaurus'' are typical of basal archosauriforms. The ectepicondylar groove on the humerus reported by Ochev is present in '' Prolacerta'', ''Proterosuchus'', phytosaurs,

s and several paracrocodylomorphs. Gower and Sennikov (2000) reported that the posterior cervical vertebrae bear well-defined facets for three-headed ribs. According to Nesbitt (2009), this trait is absent in Archosauria with the possible exception of '' Arizonasaurus'' and ''

Poposaurus ''Poposaurus'' is an extinct genus of pseudosuchian archosaur from the Late Triassic of the southwestern and eastern United States. It belongs to the clade Poposauroidea, an unusual group of Triassic pseudosuchians that includes sail-backed, bea ...

'', but was used as a

synapomorphy In phylogenetics, an apomorphy (or derived trait) is a novel Phenotypic trait, character or character state that has evolution, evolved from its ancestral form (or Plesiomorphy and symplesiomorphy, plesiomorphy). A synapomorphy is an apomorphy sh ...

of Erythrosuchia in Parrish (1992) phylogenetic analysis.

Paleobiology

Other vertebrates from the Berdyanka II locality that lived alongside ''Vjushkovisaurus'' include capitosauroid

temnospondyl Temnospondyli (from Greek language, Greek τέμνειν, ''temnein'' 'to cut' and σπόνδυλος, ''spondylos'' 'vertebra') or temnospondyls is a diverse ancient order (biology), order of small to giant tetrapods—often considered Labyrinth ...

s and the therapsid '' Nothogomphodon'', one of the last

therocephalia Therocephalia is an extinct clade of therapsids (mammals and their close extinct relatives) from the Permian and Triassic periods. The therocephalians ("beast-heads") are named after their large skulls, which, along with the structure of their te ...

ns. ''Vjushkovisaurus'' was likely a top predator in its environment along other large carnivores including '' Dongusuchus'' and '' Erythrosuchus''.

References

External links

''Vjushkovisaurus''
in the Paleobiology Database {{Taxonbar, from=Q3336421 Archosauriformes Prehistoric reptile genera Anisian genera Middle Triassic reptiles of Europe Triassic Russia Fossils of Russia Fossil taxa described in 1982