''Cryptovaranoides'' ("hidden lizard-like animal") 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 ...

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 ...

from the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. It contains a single species, ''Cryptovaranoides microlanius''. It is represented by a holotype partial skeleton as well as referred isolated bones from

Rhaetian The Rhaetian is the latest age of the Triassic Period (in geochronology) or the uppermost stage of the Triassic System (in chronostratigraphy). It was preceded by the Norian and succeeded by the Hettangian (the lowermost stage or earliest age ...

-aged fissure fill-deposits in Cromhall Quarry, near

Tortworth Tortworth is a small village and civil parish, near Thornbury in Gloucestershire, England. It has a population of 147 as of 2011. It lies on the B4509 road, which crosses the M5 motorway to the west of Tortworth. History In the Domesday Book o ...

, Gloucestershire preserved alongside the common fossil rhynchocephalian ''

Clevosaurus ''Clevosaurus'' (meaning "Gloucester lizard") is an extinct genus of rhynchocephalian reptile from the Triassic, Late Triassic and the Jurassic, Early Jurassic Period (geology), periods. Species of ''Clevosaurus'' were widespread across Pangaea, ...

''. The type specimen had been collected in 1953, but was only described as a distinct taxon in 2022. Several traits such as braincase, neck vertebrae, skull architecture, and teeth arrangement support ''Cryptovaranoides''' classification as a squamate. ''Cryptovaranoides'' marks the earliest known occurrence of a

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

squamate Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, ...

, with previous fossils known only as early as the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

; the discovery of ''Cryptovaranoides'' pushes back the estimated origin of modern squamates by 35 million years. A phylogenetic analysis placed ''Cryptovaranoides'' within the

Anguimorpha The Anguimorpha is a suborder of squamates. The group was named by Fürbringer in 1900 to include all autarchoglossans closer to '' Varanus'' and '' Anguis'' than ''Scincus ''Scincus'' is a genus of skinks, lizards in the family Scincidae. Th ...

sister A sister is a woman or a girl who shares one or more parents with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to refer to ...

to the

Neoanguimorpha Neoanguimorpha is a clade of anguimorphs comprising Monstersauria (represented today by helodermatids) and Diploglossa (Xenosauridae and Anguioidea). Morphological studies in the past had classified helodermatids with the varanoids in the clade ...

(containing modern helodermatids, anguids, and knob-scaled lizards), supporting a much more ancient estimate for the radiation of modern squamate lineages than previously assumed.

References

{{Taxonbar, from=Q115604719 Anguimorpha Triassic England Taxa named by Michael Benton Fossil taxa described in 2022