''Barasaurus'' 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 ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

owenettid Owenettidae is an extinct family of procolophonian parareptiles. Fossils have been found primarily from Africa and Madagascar, with one genus present from South America. It is the sister taxon to the family Procolophonidae. The family was const ...

procolophonoid Procolophonoidea is an extinct superfamily of procolophonian parareptiles. Members were characteristically small, stocky, and lizard-like in appearance. Fossils have been found worldwide from many continents including Antarctica. The first membe ...

parareptile 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 ...

known from the late

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 trading enterprise, a New Zealand business law ** Local average treatment effect, ...

and early

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is ...

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Afric ...

. It contains a single species, ''Barasaurus besairiei''.

Discovery

''Barasaurus besairiei'', the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specim ...

of the ''Barasaurus'', was first described and named by the French

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

Jean Piveteau Jean Piveteau (23 September 1899 – 7 March 1991) was a distinguished French vertebrate paleontologist. He was elected to the French Academy of Sciences in 1956 and served as the institute's president in 1973. References External links Membe ...

1955 Events January * January 3 – José Ramón Guizado becomes president of Panama. * January 17 – , the first nuclear-powered submarine, puts to sea for the first time, from Groton, Connecticut. * January 18– 20 – Battle of Yijian ...

on the basis of the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

MNHN P1, a natural mold of a nearly complete

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

, missing only the tail and distal limb reposited in the

Muséum national d'Histoire naturelle The French National Museum of Natural History, known in French as the ' (abbreviation MNHN), is the national natural history museum of France and a ' of higher education part of Sorbonne Universities. The main museum, with four galleries, is loc ...

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. Si ...

. The holotype was collected from the Lower Sakamena Formation of the

Sakamena Group Sakamena is a village near Betroka in the region of Anosy in Madagascar. Sakamena is also the name of a Permian sedimentary geological formation that has yielded many vertebrate fossil, including Triadobatrachus (the first lissamphibian), Claudios ...

at the Ranohira locality of

Morondava Basin Morondava Basin is one of the major sedimentary basins of Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island c ...

Fianarantsoa Fianarantsoa is a city (commune urbaine) in south central Madagascar, and is the capital of Haute Matsiatra Region. History It was built in the early 19th century by the Merina as the administrative capital for the newly conquered Betsileo kin ...

, dating to the

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 ...

stage of the late

period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

. The generic name honors the

Bara people The Bara people are a Malagasy ethnic group living in the southern part of the central plateaus of Madagascar, in the Toliara Province, concentrated around their historic capital at Ihosy. The Bara are the largest of the island's zebu-herding ...

, indigenous to the Ranohira region of Madagascar, and is derived from ''sauros'', meaning "lizard" in

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...

. The specific name, ''besairiei'', honors Henri Michel-Edouard Besairie, a French

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

who supervised the Geological Survey of Madagascar and collected the holotype specimen. Hilary F. Ketchum and Paul M. Barrett (2004) referred additional specimens from the Sakamena Group to ''Barasaurus''. They described four specimens, consisting of hind limb material: OUMNH GX.95, a

foot The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg mad ...

including the tarsus and digits; OUMNH GX.97, left

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates ...

, possible

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it conn ...

and foot; OUMNH GX.99, right tibia,

fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity ...

, and foot; and OUMNH GX.101, a foot. These specimens are housed at the

Oxford University Museum of Natural History The Oxford University Museum of Natural History, sometimes known simply as the Oxford University Museum or OUMNH, is a museum displaying many of the University of Oxford's natural history specimens, located on Parks Road in Oxford, England. It a ...

. They were collected from the "Couches à Poissons et Ammonites" Member of the

Middle Sakamena Formation Middle or The Middle may refer to: * Centre (geometry), the point equally distant from the outer limits. Places * Middle (sheading), a subdivision of the Isle of Man * Middle Bay (disambiguation) * Middle Brook (disambiguation) * Middle Creek ( ...

at the only currently known

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 dis ...

locality of the Diego Basin,

Antsiranana Antsiranana ( mg, Antsiran̈ana ), named Diego-Suárez prior to 1975, is a city in the far north of Madagascar. Antsiranana is the capital of Diana Region. It had an estimated population of 115,015 in 2013. History The bay and city originally ...

of northwestern Madagascar, dating to the

Induan The Induan is the first age of the Early Triassic epoch in the geologic timescale, or the lowest stage of the Lower Triassic series in chronostratigraphy. It spans the time between 251.902 Ma and Ma (million years ago). The Induan is someti ...

stage of the early

period.

Description

Several traits suggest that the lower Triassic and upper Permian specimens are referable to ''Barasaurus''. The presence of a fused astragalocalcaneum indicate that they belong to the

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 ...

. Among parareptiles, only specimens of ''Barasaurus'' and the millerettid ''

Broomia ''Broomia'' is an extinct genus of millerettid parareptile from the Middle Permian (Capitanian stage) of South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It ...

'' possess a fifth distal tarsal, a reversal to the primitive

condition. This trait is considered an

autapomorphy In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to ...

of both genera separately, as ''Broomia'' is easily distinguished from ''Barasaurus'' on the basis of several other characters and its phylogenetic position within

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 ...

. All specimens of ''Barasaurus'' as well as ''

Procolophon ''Procolophon'' is a genus of lizard-like procolophonid parareptiles that first appeared in the Early Triassic (Induan) of South Africa, Brazil, and Antarctica. It persisted through the Permian–Triassic extinction event, but went extinct in ...

'' share the presence of the medial flange on the proximal end of the first

metatarsal The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the me ...

, a possible

synapomorphy In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...

for Procolophonoidea. All specimens of ''Barasaurus'' are distinguished from all other procolophonians by the presence of a pedal centrale and relatively short pedal unguals, and therefore these represent two additional autapomorphic reversals of ''Barasaurus''. Although the complete pedal phalangeal count of ''Barasaurus'' is unknown from the holotype, the lower Triassic material revealed that the phalangeal formula for this genus is 2:3:4:5:5. Procolophonoid material with such arrangement is otherwise known from the Lower Sakamena Formation. These specimens are also similar to ''

Owenetta ''Owenetta'' is an extinct genus of owenettid procolophonian parareptile. Fossils have been found from the Beaufort Group in the Karoo Basin of South Africa. Although most procolophonians lived during the Triassic, ''Owenetta'' existed during ...

'', and therefore likely referable to ''Barasaurus'' as well. The presence of five phalanges in the fifth pedal digit (as seen in the phalangeal formula) is unique among

s to ''Barasaurus'' and

mesosaur Mesosaurs ("middle lizards") were a group of small aquatic reptiles that lived during the early Permian period, roughly 299 to 270 million years ago. Mesosaurs were the first known aquatic reptiles, having apparently returned to an aquatic life ...

s, however their feet are easily distinguishable on the basis of other traits, suggesting that this unusual formula represents an additional autapomorphy for ''Barasaurus''.

Phylogeny

Phylogenetic analyses place ''Barasaurus'' within the

Owenettidae Owenettidae is an extinct family of procolophonian parareptiles. Fossils have been found primarily from Africa and Madagascar, with one genus present from South America. It is the sister taxon to the family Procolophonidae. The family was const ...

, the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

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 ...

. ''Barasaurus'' forms the sister taxon to the clade containing ''

Saurodektes ''Saurodektes'' is an extinct genus of owenettid procolophonoid parareptile known from the earliest Triassic deposits of Eastern Cape Province, South Africa. It was first named by Sean P. Modesto, Ross J. Damiani, Johann Neveling and Adam M. Ya ...

'' and the only known owenettid older than ''Barasaurus'', '' Owenetta rubidgei'', while '' "Owenetta" kitchingorum'' and '' Candelaria'' form another lineage within the family. The addition of ''

Ruhuhuaria ''Ruhuhuaria'' is an extinct genus of owenettid procolophonoid reptile known from the Middle Triassic Manda Beds of southwestern Tanzania. ''Ruhuhuaria'' is known solely from the holotype CAMZM T997, poorly preserved but complete skull and man ...

'' to the phylogenetic analysis resulted in less resolved relation within Owenettidae, however ''Barasaurus'' and ''Owenetta rubidgei'' are recovered as sister taxa.

References

{{Taxonbar, from=Q16748765 Fossil taxa described in 1955 Procolophonomorphs Permian reptiles of Africa Early Triassic reptiles of Africa Triassic parareptiles Prehistoric reptile genera