Fossil of '' Labidosaurus hamatus'' Captorhinida (older name: Cotylosauria) is a doubly

paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...

grouping of early

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates ( lizards and snakes) and rhynchocephalia ...

s. Robert L. Carroll (1988) ranked it as an order in the subclass

Anapsid An anapsid is an amniote whose skull lacks one or more skull openings (fenestra, or fossae) near the temples. Traditionally, the Anapsida are the most primitive subclass of amniotes, the ancestral stock from which Synapsida and Diapsida evolv ...

a, composed of the following suborders:R. L. Carroll (1988), '' Vertebrate Paleontology and Evolution'', W. H. Freeman and Company, New York * A paraphyletic Captorhinomorpha, containing the families Protorothyrididae, Captorhinidae, Bolosauridae,

Acleistorhinidae Acleistorhinidae is an extinct family of Late Carboniferous and Early Permian-aged ( Moscovian to Kungurian stage) parareptiles. Acleistorhinids are most diverse from the Richards Spur locality of the Early Permian of Oklahoma. Richards Spur acle ...

and possibly also Batropetidae *

Procolophonia The Procolophonia are a suborder of herbivorous reptiles that lived from the Middle Permian till the end of the Triassic period. They were originally included as a suborder of the Cotylosauria (later renamed Captorhinida Carroll 1988) but are n ...

, containing families

Nyctiphruretidae Nyctiphruretidae is an extinct family of hallucicranian parareptiles known from the late Early to the late Middle Permian of European Russia and south-central United States. Nyctiphruretidae was named by Efremov in 1938. The type genus is '' Ny ...

Procolophonidae Procolophonidae is an extinct family of small, lizard-like parareptiles known from the Late Permian to Late Triassic that were distributed across Pangaea, having been reported from Europe, North America, China, South Africa, South America, Anta ...

and Sclerosauridae * Pareiasauroidea, with families Rhipaeosauridae and Pareiasauridae * Millerosauroidea, with a single family Millerettidae. While they all share primitive features and resemble the ancestors of all modern reptiles, some of these families are more closely related to (or belong to) the clade

Parareptilia Parareptilia ("at the side of reptiles") is a subclass or clade of basal sauropsids (reptiles), typically considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds). Parareptiles first arose near th ...

, while others are further along the line leading to

diapsid Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The group first appeared about three hundred million years a ...

s. For this reason, the group is only used informally, if at all, by most modern paleontologists. All members of this group are thought to be extinct.

References

Prehistoric reptile taxonomy Prehistoric animal orders Tetrapod orders Paraphyletic groups {{Paleo-reptile-stub