''Babibasiliscus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of casquehead lizard (family Corytophanidae) that lived in what is now Wyoming during the early

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

, approximately 48 million years ago. The genus is known from a single species, ''Babibasiliscus alxi'', which was named by paleontologist Jack Conrad in 2015 on the basis of a fossilized skull from the

Bridger Formation The Bridger Formation is a Formation (geology), geologic formation in southwestern Wyoming. It preserves fossils dating back to the Bridgerian and Uintan North American land mammal age, stages of the Paleogene Period (geology), Period. The formati ...

in the

Green River Basin Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 nm. In subtractive color systems, used in painting and color printing, it is created by a combin ...

. The name ''Babibasiliscus'' comes from the

Shoshoni The Shoshone or Shoshoni ( or ), also known by the endonym Newe, are an Indigenous people of the United States with four large cultural/linguistic divisions: * Eastern Shoshone: Wyoming * Northern Shoshone: Southern Idaho * Western Shoshone ...

word ''babi'', meaning "older male cousin", and ''

Basiliscus Basiliscus (; died 476/477) was Eastern Roman emperor from 9 January 475 to August 476. He became in 464, under his brother-in-law, Emperor Leo I (457–474). Basiliscus commanded the army for an invasion of the Vandal Kingdom in 468, which ...

'', a modern-day genus of casquehead lizards. The specimen is undeformed and nearly complete except for the tip of the snout and the top of the skull, making it unclear whether the distinctive bony crest of living corytophanids was present in prehistoric relatives like ''Babibasiliscus''. The skull is about in length and the entire body is estimated to have been about long. Bones on the right side of lower jaw of the specimen are thickened and fused together, suggesting that the jaw had broken and healed when the animal was alive. ''Babibasiliscus'' occurs farther north than any living genus of corytophanid. During the Eocene temperatures in what is now Wyoming were about warmer than they are today, and the region was likely covered by a tropical forest based on other Eocene fossil assemblages known from western North America.

Phylogenetic analysis In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data ...

indicates that ''Babibasiliscus'' is deeply nested within Corytophanidae as the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

of the living genus ''

Laemanctus ''Laemanctus'' is a genus of lizards in the Family (biology), family Corytophanidae. Species in the genus ''Laemanctus'' are commonly referred to as conehead lizards or casquehead iguanas. The genus is Endemism, endemic to Central America. Desc ...

''. Below is a

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

from Conrad's description of ''Babibasiliscus'' showing its relationships to other corytophanids:

References

Corytophanidae Eocene lepidosaurs Fossil taxa described in 2015 Eocene reptiles of North America Paleontology in Wyoming {{paleo-lizard-stub