Protorothyrididae is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

family of small, lizard-like reptiles belonging to Eureptilia. Their skulls did not have fenestrae, like the more derived

diapsids 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 ...

. Protorothyridids lived from the Late Carboniferous to

Early Permian 01 or '01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * '01 (Richard Müller album), 01'' (Richard Müller album), 2001 * 01 (Son of Dave album), ''01'' (Son of Dave album), 2000 * 01 (Urban ...

periods, in what is now

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. Many genera of primitive reptiles were thought to be protorothyridids. ''

Brouffia ''Brouffia'' is an extinct genus of Late Carboniferous (late Westphalian stage) basal reptile known from Pilsen of Czech Republic. It is known from a single partial skeleton, the holotype ČGH III B.21.C.587 and MP 451 (part and ...

'', ''

Coelostegus ''Coelostegus'' is an extinct genus of Late Carboniferous (late Westphalian stage) basal reptile known from Pilsen of Czech Republic. It is known from the holotype ČGH 3027, a partial skeleton of an immature individual. It was collect ...

'', ''

Paleothyris ''Paleothyris'' was a small, agile, anapsid romeriidan reptile which lived in the Middle Pennsylvanian epoch in Nova Scotia (approximately 312 to 304 million years ago). ''Paleothyris'' had sharp teeth and large eyes, meaning that it was like ...

'' and '' Hylonomus'', for example, were found to be more

basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

eureptiles in Muller and Reisz (2006), making the family as historically defined

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 ...

, though three genera, ''

Protorothyris ''Protorothyris'' is an extinct genus of Early Permian protorothyridid known from Texas and West Virginia of the United States. It was first named by Llewellyn Ivor Price in 1937 and the type species is ''Protorothyris archeri''. ''P. archeri ...

, Anthracodromeus,'' and '' Cephalerpeton'', were recovered as a

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

group. ''Anthracodromeus'', ''Paleothyris'', and ''Protorothyris w''e recovered as a monophyletic group in Ford and Benson (2020) (who did not sample ''Cephalerpeton''), who recovered them as more derived than

captorhinids 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 C ...

and ''Hylonomus'', but less so than

araeoscelidians Araeoscelidia or Araeoscelida is a clade of extinct diapsid reptiles superficially resembling lizards, extending from the Late Carboniferous to the Early Permian. The group contains the genera '' Araeoscelis'', ''Petrolacosaurus'', the possi ...

. ''Anthracodromeus'' is the earliest known reptile to display adaptations to climbing. The majority of phylogenetic studies recover protorothyridids as

members of Eureptilia; however, Simões ''et al.'' (2022) recover them as

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

amniote Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are disti ...

s instead.

References

Prehistoric reptile families Prehistoric romeriids Taxa named by Llewellyn Ivor Price {{paleo-reptile-stub