''Polrussia'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of iguanian

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

s dating to the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

epoch, found in what is now Mongolia. It belongs to a group of extinct iguanians called

Gobiguania Gobiguania is an extinct clade of iguanian lizards from the Late Cretaceous. All known gobiguanians are endemic to the Gobi Desert of Mongolia. Gobiguania was given a phylogenetic definition by Jack Conrad and Mark Norell in 2007 as all taxa mor ...

that was endemic to the

Gobi Desert The Gobi Desert (Chinese: 戈壁 (沙漠), Mongolian: Говь (ᠭᠣᠪᠢ)) () is a large desert or brushland region in East Asia, and is the sixth largest desert in the world. Geography The Gobi measures from southwest to northeast an ...

during the Late Cretaceous. The

type species In 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 species that contains the biological type specimen ...

''Polrussia mongoliensis'' was named in 1991 on the basis of a skull found in the Barun Goyot Formation. The genus name refers to the Polish and Russian paleontologists who worked together to find and describe the material. ''Polrussia'' has a short skull, slightly pointed and flattened snout, and large eye sockets. The teeth each have one cusp, as opposed to the multiple cusps seen in some other gobiguanians. The skull is only long, making ''Polrussia'' one of the smallest gobiguanians. Below is a cladogram from Daza ''et al.'' (2012) showing the phylogenetic relationships of ''Polrussia'':

References

Cretaceous lizards Late Cretaceous reptiles of Asia Fossil taxa described in 1991 Prehistoric lizard genera {{paleo-lizard-stub