Polrussia

Polrussia Temporal range: Late Cretaceous
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Iguania
Clade:	†Gobiguania
Genus:	†Polrussia Borsuk-Białynicka and Alifanov, 1991
Type species
†Polrussia mongoliensis Borsuk-Białynicka and Alifanov, 1991

Polrussia is an extinct genus of iguanian lizard dating to the Late Cretaceous epoch, found in what is now Mongolia. It belongs to a group of extinct iguanians called Gobiguania that was endemic to the Gobi Desert during the Late Cretaceous. The type species 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 1.2 centimetres (0.47 in) long, making Polrussia one of the smallest gobiguanians.

Below is a cladogram from Daza et al. (2012) showing the phylogenetic relationships of Polrussia:

Iguania

†Hoyalacerta sanzi †Huehuecuetzpalli mixtecus †Pristiguana brasiliensis Chamaeleontiformes †Priscagamidae Acrodonta Iguanoidea (=Pleurodonta) Silvaiguana Hoplocercidae Polychrotidae †Gobiguania †Polrussia mongoliensis †Igua minuta †Isodontosaurus gracilis †Anchaurosaurus gilmorei †Zapsosaurus sceliphros †Saichangurvel davidsoni †Temujinia ellisoni †Ctenomastax parva Euiguana Corytophanidae Terraiguana Iguanidae Crotaphytidae Phrynosomatidae Opluridae †Uquiasaurus Liolaemidae Leiocephalus Tropiduridae