Priscagamidae is an extinct

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

iguania Iguania is an infraorder of squamate reptiles that includes iguanas, chameleons, agamids, and New World lizards like anoles and phrynosomatids. Using morphological features as a guide to evolutionary relationships, the Iguania are believed ...

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 known from 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 ...

of Mongolia and China and the

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

of India, spanning a range from 75 to 54 million years ago. It includes the

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

Heterodontagama ''Heterodontagama'' is an extinct genus of iguanian lizard from the Early Eocene of India. It belongs to the extinct family Priscagamidae, which is otherwise only known from the Late Cretaceous of Mongolia. The type species ''Heterodontagama bors ...

'', ''

Mimeosaurus ''Mimeosaurus'' is an extinct genus of iguanian lizard from the Late Cretaceous of Mongolia. It is part of an extinct family of iguanians called Priscagamidae, and was the first priscagamid to have been described, having been named by American pa ...

'', ''

Phrynosomimus ''Phrynosomimus'' is an extinct genus of iguanian lizard from the Late Cretaceous of Mongolia belonging to the extinct family Priscagamidae. The type species ''Phrynosomimus asper'' was named in 1996. Fossils have been found in the Barun Goyot a ...

'', ''

Priscagama ''Priscagama'' (meaning "earliest '' Agama''" in Latin) is an extinct genus of iguanian lizard from the Late Cretaceous of Mongolia and China. It belongs to an extinct family of iguanians called Priscagamidae (or subfamily Priscagaminae). Several ...

'', and possibly ''

Pleurodontagama ''Pleurodontagama'' is an extinct genus of iguanian lizard from the Late Cretaceous of Mongolia. The type species, ''Pleurodontagama aenigmatodes'', was named in 1984 on the basis of a mostly complete skull and isolated lower jaw from a fossil lo ...

''. The first fossils of priscagamids were found in the Djadochta and Khermeen Tsav formations of Mongolia. More recently they have been found in the Cambay Formation in India, leading to the naming of ''Heterodontagama'' in 2013. Priscagamidae was originally described as a subfamily of

Agamidae Agamidae is a family (biology), family of over 300 species of iguanian lizards indigenous to Africa, Asia, Australia, and a few in Southern Europe. Many species are commonly called dragons or dragon lizards. Overview phylogenetics, Phylogenetic ...

called Priscagaminae in 1984, but it was reclassified as a distinct family in 1989. Most

phylogenetic analyses In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

(analyses of evolutionary relationships) still find a close relationship between Priscagamidae and Agamidae (both have been grouped under a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

called

Chamaeleontiformes Chamaeleontiformes is a hypothesized clade (evolutionary grouping) of iguanian lizards defined as all taxa sharing a most recent common ancestor, more recent common ancestor with ''Chamaeleo chamaeleon'' (the common chamaeleon) than with ''Hoploc ...

), although a 2015 study found it to be basal to all other iguanian clades, warranting its removal from Iguania and placement in a larger clade called

Iguanomorpha Iguania is an infraorder of squamate reptiles that includes iguanas, chameleons, agamids, and New World lizards like anoles and phrynosomatids. Using morphological features as a guide to evolutionary relationships, the Iguania are believed t ...

References

Cretaceous lizards Prehistoric reptiles of Asia Late Cretaceous first appearances Eocene extinctions Fossil taxa described in 1984 Prehistoric reptile families {{paleo-lizard-stub