Drepanosaur

Drepanosaurs Temporal range: Late Triassic, 230–201.3 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Fossil specimen of Drepanosaurus unguicaudatus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Neodiapsida
Clade:	†Drepanosauromorpha Renesto et al., 2010
Subgroups
†Hypuronector †Kyrgyzsaurus †Longisquama? †Protoavis? †Elyurosauria †Vallesaurus †Drepanosauridae †Ancistronychus †Dolabrosaurus †Skybalonyx †Unguinychus †Megalancosaurinae †Drepanosaurus †Megalancosaurus †Avicranium

Drepanosaurs (members of the clade Drepanosauromorpha) are a group of extinct reptiles that lived between the Carnian and Rhaetian stages of the late Triassic Period, approximately between 230 and 210 million years ago.^[1] The various species of drepanosaurs were characterized by a bird-like skull, a barrell shaped body, and a horizontally narrow tail. A number of drepanosaurs had specialized grasping limbs and often prehensile tails similar to those of chameleons. Drepanosaurs are generally thought to have been arboreal (tree-dwelling),^[2] and probably insectivores.^[3] Some studies have alternately suggested fossorial (digging) and aquatic lifestyles for some members.^[4] Fossils of drepanosaurs have been found in North America (Arizona, New Mexico, New Jersey, Utah) and Europe (England and northern Italy). The name is taken from the family's namesake genus Drepanosaurus, which means "sickle lizard," a reference to their strongly curved claws.

Some studies have included Drepanosaurs within the group Avicephala, which also includes the gliding Weigeltisauridae, but the close relationship between the two groups has been doubted by other authors. Their phylogenetic position has been disputed, with some studies considering them to be members of Archosauromorpha (and thus more closely related to modern birds and crocodilians than to lizards), while other studies have considered them to be basal neodiapsids that are not related to any modern reptiles.^[2]