Pareiasauromorpha is a group of parareptilian

amniotes 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 distingu ...

from the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

. It includes genera found all over the world, with many genera from

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

and

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

. The

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

was first used as a group by Linda A. Tsuji in

2011 File:2011 Events Collage.png, From top left, clockwise: a protester partaking in Occupy Wall Street heralds the beginning of the Occupy movement; protests against Libyan dictator Muammar Gaddafi, who was killed that October; a young man celebrate ...

, in order to group the family

Nycteroleteridae 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)''. Th ...

(nycteroleters) and the superfamily

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, ...

(pareiasaurs). Pareiasauromorpha is considered to be 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 ...

node, the sister group to procolophonoids.

Classification

''Pareiasauromorpha'' was first used to define a group of

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 ...

ns in

by Linda A. Tsuji. The next year, Tsuji and her colleagues used Pareiasauromorpha as a node inside

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 ...

. In their 2012 publication, Tsuji ''et al.'' defined it as a

node containing "nycteroleters" (the family

) and "pareiasaurs" (in the superfamily

Nycteroleteridae

Nycteroleteridae is a family, commonly called "nycteroleters", classified in Pareiasauromorpha. The group includes the genera ''

Emeroleter ''Emeroleter'' is an extinct genus of nycteroleterid parareptile known from the early Late Permian Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dement ...

'', ''

Nycteroleter ''Nycteroleter'' is an extinct genus of nycteroleterid parareptile known from the Middle Permian of European Russia. Fossils were first found in the Mezen River, near to Arkhangelsk. Within the Nycteroleteridae, it is considered most closely re ...

'', '' Bashykroleter'', ''

Rhipaeosaurus ''Rhipaeosaurus'' is an extinct genus of nycteroleterid parareptile known from an articulated skeleton from the mid Middle Permian of European Russia. It contained a single species, ''Rhipaeosaurus tricuspidens''. A bayesian analysis suggests t ...

'', ''

Macroleter ''Macroleter'' is an extinct genus of nycteroleterid parareptile which existed in Oklahoma and Russia during the upper Permian period. It was a quite generalized primitive reptile, in many ways resembling their amphibian ancestors. It was firs ...

'', and "Bashykroleter" ''mesensis''. The genus ''

Tokosaurus ''Macroleter'' is an extinct genus of nycteroleterid parareptile which existed in Oklahoma and Russia during the upper Permian period. It was a quite generalized primitive reptile, in many ways resembling their amphibian ancestors. It was firs ...

'' is often classified as the sister taxon to ''Macroleter'', but is actually more likely a juvenile of the later. ''Bashykroleter'', including both species, is now considered

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 ...

, as "B." ''mesensis'' is more closely related to other genera than the type species ''B. bashkyricus''.

Pareiasauroidea

Pareiasauroidea is a superfamily, called "pareiasaurs", that is classified as the sister group to "nycteroleters". It includes many genera, and in some classifications, is grouped with ''Macroleter'' as the most basal member, or the sister taxon, with ''Macroleter'' outside of Nycteroleteridae. Apart from the possible genus ''Macroleter'', the species "

Bradysaurus ''Bradysaurus'' was a large, early and common pareiasaur, the fossils of which are known from the ''Tapinocephalus'' Assemblage Zone (Capitanian age) of the South African Karoo. Along with the similarly large dinocephalia, the bradysaurs cons ...

" ''seeleyi'' is often classified outside its genus as the most primitive species, with the genus also classified as basal.

Phylogeny

The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

below was found in 2011 by Tsuji, and modified in

2012 File:2012 Events Collage V3.png, From left, clockwise: The passenger cruise ship Costa Concordia lies capsized after the Costa Concordia disaster; Damage to Casino Pier in Seaside Heights, New Jersey as a result of Hurricane Sandy; People gather ...

by Tsuji ''et al.'': Bradysaurus baini

A later study of parareptilian relationships published by Cisneros ''et al.'' (2021) recovered a diphyletic

Lanthanosuchoidea Lanthanosuchoidea is an extinct superfamily of ankyramorph parareptiles from the middle Pennsylvanian to the middle Guadalupian epoch ( Moscovian - Wordian In the geologic timescale, the Wordian is an age or stage of the Permian. It is th ...

, with ''

Lanthanosuchus ''Lanthanosuchus'' is an extinct genus of parareptile from the Late Permian. It was found at Isheevo in Tatarstan The Republic of Tatarstan (russian: Республика Татарстан, Respublika Tatarstan, p=rʲɪsˈpublʲɪkə tət ...

'' nested within Pareiasauromorpha:

Distribution

Pareiasauromorphs are known from across the globe, with large numbers of genera from the

Karoo Basin The Karoo Supergroup is the most widespread stratigraphy, stratigraphic unit in Africa south of the Kalahari Desert. The group (stratigraphy), supergroup consists of a sequence of units, mostly of nonmarine origin, deposited between the Pennsylvan ...

, and

. Among pareiasaurs, the genera ''

Pareiasaurus ''Pareiasaurus'' is an extinct genus of pareiasauromorph reptile from the Permian period. It was a typical member of its family, the pareiasaurids, which take their name from this genus. Fossils have been found in the Beaufort Group. Descript ...

'', '' Anthodon'', ''Bradysaurus'', '' Pareiasuchus'', '' Embrithosaurus'', ''

Nochelesaurus ''Embrithosaurus'' was a pareiasaur from the Permian of South Africa. Description ''Embrithosaurus'' was in length and in weight. The skull is relatively deep and narrow. The body is lightly armoured with thin, smooth dermal scutes. Species ...

'', ''

Nanoparia ''Nanoparia'' is an extinct genus of pareiasaur that lived in the Permian. Description It was about 60 cm in length, and weighed around 8 to 10 kilograms. Classification This is an unusual small, spiny specialised form. The skull is ve ...

'', ''

Pumiliopareia ''Pumiliopareia'' is an extinct genus of pareiasauridae, pareiasaurid parareptile from the Permian period of South Africa. It is known from a complete skeleton with osteoderms. Description ''Pumiliopareia'' was about 50 cm in length with a ...

'' and "The Welgevonden Pareiasaur" are known from the Karoo Basin; ''

Scutosaurus ''Scutosaurus'' ("shield lizard") is an extinct genus of pareiasaur parareptiles. Its genus name refers to large plates of armor scattered across its body. It was a large anapsid reptile that, unlike most reptiles, held its legs underneath its b ...

'', '' Obirkovia'' and ''

Deltavjatia ''Deltavjatia'' was a pareiasauromorph procolophonoid from the Tatarian stage of the Permian time period. It had a large body of about in length. ''Deltavjatia'' was an herbivore and lived in what is now Russia. The first specimen of ''Delta ...

'' are from

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

; '' Shihtienfenia'', '' Shanchuansaurus'' and ''

Shansisaurus ''Shihtienfenia'' was a pareiasaurid parareptile from the Late Permian Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority tradin ...

'' are from

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

; ''

Parasaurus ''Parasaurus'' (meaning "near lizard") is a genus of pareiasaur known from fossils collected in the Kupferschiefer in Germany (Hesse, Thuringia and Lower Saxony), dating to the Late Permian (Wuchiapingian). The type species, ''Parasaurus geinit ...

'' is known from

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

; ''

Bunostegos ''Bunostegos'' ("knobbly kullroof") is an extinct genus of pareiasaur parareptile from the Late Permian of the Agadez Region in Niger. The type species, ''Bunostegos akokanensis'', was named from the Moradi Formation in 2003. It was a cow-size ...

'' is known from

Niger ) , official_languages = , languages_type = National languagesArganaceras ''Arganaceras'' ("Argana horn") is a medium-sized pareiasaur from the Late Permian Ikakern Formation of Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It o ...

'' is from

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...

; ''

Provelosaurus ''Provelosaurus'' is an extinct Pareiasaur genus of the Late Permian found on the road between Aceguá and Bagé in the Paleorrota, Rio Grande do Sul, Brazil. Found in the Rio do Rasto Formation, aged about 260 million years.http://www.ufrgs ...

'' is known from

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

; and ''

Elginia ''Elginia'' is an extinct genus of pareiasaurid known from the Late Permian of Scotland and China. It was named for the area around Elgin in Scotland, which has yielded many fossils referred to as the Elgin Reptiles. Discovery The type s ...

'' is from

Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...

. Though pareiasaurs are widely distributed, all six known nycteroleters are currently only known from Russia. The group ranges in age from the earliest

Guadalupian The Guadalupian is the second and middle series/epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± 0. ...

(271

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago). ...

) until the latest

Lopingian The Lopingian is the uppermost series/last epoch of the Permian. It is the last epoch of the Paleozoic. The Lopingian was preceded by the Guadalupian and followed by the Early Triassic. The Lopingian is often synonymous with the informal terms l ...

(about 251 million years ago).

References

{{Taxonbar, from=Q16756895 Pareiasauromorphs Fossil taxa described in 2012