''Igua'' 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 belonging to a group 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 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 ...

. 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 ...

''Igua minuta'' was named in 1991 on the basis of a skull from the Barun Goyot Formation in Mongolia. The skull itself is very small, only long, and may have belonged to a juvenile given that it possesses a large

fontanelle A fontanelle (or fontanel) (colloquially, soft spot) is an anatomical feature of the infant human skull comprising soft membranous gaps ( sutures) between the cranial bones that make up the calvaria of a fetus or an infant. Fontanelles allow f ...

and that many of the bones are unfused. The snout-vent length of the individual (the total body length minus the tail) is estimated to have been . ''Igua'' differs from related gobiguanians like ''

Polrussia ''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 ...

'' in having a more rounded skull. It is similar in appearance to the living genera '' Liolaemus'' and ''

Tropidurus ''Tropidurus'' is a genus of reptiles. The genus includes many species of Neotropical ground lizards (family Tropiduridae). ''Tropidurus'' is the type genus of the family Tropiduridae. Geographic range and habitat Species in the genus ''Tropid ...

''. The teeth are tricuspid and pleurodont, meaning they are attached to inner surfaces of the jaws. Below is a cladogram from Daza ''et al.'' (2012) showing the phylogenetic relationships of ''Igua'':

References

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