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

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

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 rhynchocephalians ( ...

Robert L. Carroll Robert "Bob" Lynn Carroll (May 5, 1938 – April 8, 2020) was an American–Canadian vertebrate paleontologist who specialised in Paleozoic and Mesozoic amphibians and reptiles. Biography Carroll was an only child and grew up on a farm ne ...

(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 evolve ...

a, composed of the following suborders:R. L. Carroll (1988), ''

Vertebrate Paleontology and Evolution ''Vertebrate Paleontology and Evolution'' is an advanced textbook on vertebrate paleontology by Robert L. Carroll, published in 1988 by WH Freeman. It provides a very detailed technical account of various groups of living and fossil vertebrate ...

'', W. H. Freeman and Company, New York * A paraphyletic Captorhinomorpha, containing the families

Protorothyrididae Protorothyrididae is an extinct family of small, lizard-like reptiles belonging to Eureptilia. Their skulls did not have fenestrae, like the more derived diapsids. Protorothyridids lived from the Late Carboniferous to Early Permian periods, ...

Captorhinidae Captorhinidae (also known as cotylosaurs) is an extinct family of tetrapods, traditionally considered primitive reptiles, known from the late Carboniferous to the Late Permian. They had a cosmopolitan distribution across Pangea. Description ...

Bolosauridae Bolosauridae is an extinct family of ankyramorph parareptiles known from the latest Carboniferous (Gzhelian) or earliest Permian (Asselian) to the early Guadalupian epoch (latest Roadian stage) of North America, China, Germany, Russia and France. ...

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 ...

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 ...

, containing families

Nyctiphruretidae Nyctiphruretidae is an extinct family (biology), family of hallucicranian parareptiles known from the late Early Permian, Early to the late Middle Permian of European Russia and south-central United States. Nyctiphruretidae was named by Efremov ...

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, Antarc ...

and

Sclerosauridae 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, Antarc ...

Pareiasauroidea Pareiasaurs (meaning "cheek lizards") are an extinct clade of large, herbivorous parareptiles. Members of the group were armoured with scutes which covered large areas of the body. They first appeared in southern Pangea during the Middle Permian, ...

, with families

Rhipaeosauridae Nycteroleteridae is a family of procolophonian parareptilians (extinct early reptiles) from the Middle to Late Permian of Russia and North America. They are sometimes classified as a sister group to pareiasaurids (but see ''Classification)''. T ...

and Pareiasauridae *

Millerosauroidea Millerosauria is an order of Parareptiles that contains the families †Millerettidae and †Eunotosauridae. It is the sister group to the order Procolophonomorpha. It was named in 1957 by Watson. It was once considered a suborder of the disused ...

, with a single family

Millerettidae Millerettidae is an extinct family of parareptiles from the Middle Permian to the Late Permian period (Capitanian - Changhsingian stages) of South Africa. The millerettids were small insectivores and probably resembled modern lizards in appearanc ...

. 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 the ...

, 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 ago ...

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