Chalishevia

Chalishevia Temporal range: Ladinian ~242–237  Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Diagram showing the known skull remains of the holotype individual
Chalishevia
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauriformes
Family:	† Erythrosuchidae
Genus:	† Chalishevia Ochev, 1980
Species
†C. cothurnataOchev, 1980 (type)

Size comparison of Chalishevia (skeletal reconstruction based from Shansisuchus )

Chalishevia is an extinct genus of erythrosuchid archosauriform (quadrupedal, large-headed terrestrial carnivore) from the Ladinian Bukobay Formation of Russia (Orenburg Oblast), likely making it the youngest known erythrosuchid in the geological time scale. ^{[1] [2]} Though it is only known from some fragmentary cranial material, the skull is estimated to be around 80 centimeters long, making it one of the largest erythrosuchids known. ^[1]

Due to a breakage in the nasal/maxilla region, these bones were previously (and likely, innacurately) interpreted to sharply converge to eachother anteriorly, resulting in a very triangular snout, and a strongly constricted region behind the premaxilla

What is known of its anatomy is very similar to that of Shansisuchus (likely indicating a close phylogenetic relationship), ^{[3] [1]} sharing a large additional fenestra in the skull behind the nostrils, between the premaxilla and maxilla bones, and roofed by the nasal. This fenestra has been described as the "accessory antorbital fenestra" or "sub-narial fenestra".

Besides the holotype, two bone fragments of the same part of the skull from two other different individuals have been described, one being noticeably smaller than the holotype (possibly a juvenile animal).

Several vertebrae and a jaw bone are also known near the region, but due to lack of overlap between the preserved bones of the holotype, these have been referred to Erythrosuchidae indet.

References

1. Butler, R.J.; Sennikov, A.G.; Ezcurra, M.D.; Gower, D.J. (2019). "The last erythrosuchid—a revision of Chalishevia cothurnata from the late Middle Triassic of European Russia". Acta Palaeontologica Polonica. 64 (4): 757–774. doi: 10.4202/app.00648.2019 . hdl: 11336/123959 .
2. Ochev, VG (1980). "New archosaurs from the Middle Triassic of the southern Cis-Urals". Paleontologicheskii Zhurnal. 1980 (101–107).
3. Ezcurra, Martín D. (2016-04-28). "The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms". PeerJ. 4 e1778. doi: 10.7717/peerj.1778 . ISSN   2167-8359. PMC   4860341 . PMID   27162705.