Polrussia is an extinct genus of iguanian lizards 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
†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
†Huehuecuetzpalli mixtecus †Pristiguana brasiliensis
†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
Chamaeleontiformes†Priscagamidae Acrodonta
†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
Silvaiguana Hoplocercidae Polychrotidae †Gobiguania †Polrussia mongoliensis †Igua minuta †Isodontosaurus gracilis †Anchaurosaurus gilmorei †Zapsosaurus sceliphros †Saichangurvel davidsoni †Temujinia ellisoni †Ctenomastax parva
SilvaiguanaHoplocercidae Polychrotidae
Hoplocercidae
Polychrotidae
†Gobiguania†Polrussia mongoliensis †Igua minuta †Isodontosaurus gracilis †Anchaurosaurus gilmorei †Zapsosaurus sceliphros †Saichangurvel davidsoni †Temujinia ellisoni †Ctenomastax parva
†Polrussia mongoliensis
†Igua minuta
†Isodontosaurus gracilis
†Anchaurosaurus gilmorei †Zapsosaurus sceliphros
†Anchaurosaurus gilmorei
†Zapsosaurus sceliphros
†Saichangurvel davidsoni †Temujinia ellisoni †Ctenomastax parva
†Saichangurvel davidsoni
†Temujinia ellisoni †Ctenomastax parva
†Temujinia ellisoni
†Ctenomastax parva
EuiguanaCorytophanidae Terraiguana Iguanidae Crotaphytidae Phrynosomatidae Opluridae †Uquiasaurus Liolaemidae Leiocephalus Tropiduridae
Corytophanidae
Terraiguana
Iguanidae Crotaphytidae Phrynosomatidae Opluridae †Uquiasaurus Liolaemidae Leiocephalus Tropiduridae
Iguanidae Crotaphytidae
Iguanidae
Crotaphytidae
Phrynosomatidae Opluridae †Uquiasaurus Liolaemidae Leiocephalus Tropiduridae
Phrynosomatidae
Opluridae †Uquiasaurus Liolaemidae Leiocephalus Tropiduridae
Opluridae
†Uquiasaurus Liolaemidae Leiocephalus Tropiduridae
†Uquiasaurus
Liolaemidae Leiocephalus Tropiduridae
Liolaemidae
Leiocephalus Tropiduridae
Leiocephalus
Tropiduridae