{{Short description|Extinct genus of reptiles}} {{confused|Barosaurus}} {{Automatic taxobox | fossil_range = Late Permian - Early Triassic, {{fossil_range|Lopingian|Induan}} | image = Barasaurus.jpg | taxon = Barasaurus | authority = Piveteau, 1955 | type_species = {{extinct}}'''''Barasaurus besairiei''''' | type_species_authority = Piveteau, 1955 }}
'''''Barasaurus''''' is an extinct genus of owenettid procolophonoid parareptile known from the Late Permian and Early Triassic of Madagascar. It contains a single species, '''''Barasaurus besairiei'''''.<ref name=Barasaurus>{{cite journal |last=Piveteau |first=Jean |year=1955 |title=Existence d'un Reptile du groupe des Procolophonidés à Madagascar - Conséquences stratigraphiques et paléontologiques |journal=Comptes rendus hebdomadaires des séances de l'Académie des Sciences |volume=241 |pages=1325–1327 }}</ref><ref name=KetchumBarrett04>{{Cite journal | last1 = Ketchum | first1 = H. F. | last2 = Barrett | first2 = P. M. | doi = 10.1139/E03-084 | title = New reptile material from the Lower Triassic of Madagascar: Implications for the Permian–Triassic extinction event | journal = Canadian Journal of Earth Sciences | volume = 41 | pages = 1 | year = 2004 | issue = 1 | bibcode = 2004CaJES..41....1K }}</ref>
==Discovery== ''Barasaurus besairiei'', the type species of the ''Barasaurus'', was first described and named by the French paleontologist Jean Piveteau in 1955 on the basis of the holotype MNHN P1, a natural mold of a nearly complete skeleton, missing only the tail and distal limb reposited in the Muséum national d'Histoire naturelle, Paris. The holotype was collected from the Lower Sakamena Formation of the Sakamena Group at the Ranohira locality of Morondava Basin, Fianarantsoa, dating to the Lopingian stage of the late Late Permian period. The generic name honors the Bara people, indigenous to the Ranohira region of Madagascar, and is derived from ''sauros'', meaning "lizard" in Ancient Greek. The specific name, ''besairiei'', honors Henri Michel-Edouard Besairie, a French geologist who supervised the Geological Survey of Madagascar and collected the holotype specimen.<ref name=Barasaurus/><ref name=BarasaurusThesis>{{cite journal |last=Meckert |first=Dirk |year=1995 |title=The procolophonid ''Barasaurus'' and the phylogeny of early amniotes |journal=McGill University |volume=Dissertation |pages=149 pp}}</ref>
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 including the tarsus and digits; OUMNH GX.97, left femur, possible tibia and foot; OUMNH GX.99, right tibia, fibula, and foot; and OUMNH GX.101, a foot. These specimens are housed at the Oxford University Museum of Natural History. They were collected from the "Couches à Poissons et Ammonites" Member of the Middle Sakamena Formation at the only currently known amniote locality of the Diego Basin, Antsiranana of northwestern Madagascar, dating to the Induan stage of the early Early Triassic period.<ref name=KetchumBarrett04/>
==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.<ref name=KetchumBarrett04/> Among parareptiles, only specimens of ''Barasaurus'' and the millerettid ''Broomia'' possess a fifth distal tarsal, a reversal to the primitive amniote condition. This trait is considered an autapomorphy of both genera separately, as ''Broomia'' is easily distinguished from ''Barasaurus'' on the basis of several other characters and its phylogenetic position within Parareptilia.<ref name=KetchumBarrett04/><ref name=BarasaurusThesis/> All specimens of ''Barasaurus'' as well as ''Procolophon'' share the presence of the medial flange on the proximal end of the first metatarsal, a possible synapomorphy 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''.<ref name=KetchumBarrett04/><ref name=BarasaurusThesis/>
Although the complete pedal phalangeal count of ''Barasaurus'' is unknown from the holotype,<ref name=BarasaurusThesis/> the lower Triassic material revealed that the phalangeal formula for this genus is 2:3:4:5:5.<ref name=KetchumBarrett04/> Procolophonoid material with such arrangement is otherwise known from the Lower Sakamena Formation. These specimens are also similar to ''Owenetta'', 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 amniotes to ''Barasaurus'' and mesosaurs, however their feet are easily distinguishable on the basis of other traits, suggesting that this unusual formula represents an additional autapomorphy for ''Barasaurus''.<ref name=KetchumBarrett04/>
==Phylogeny== Phylogenetic analyses place ''Barasaurus'' within the Owenettidae, the sister taxon of Procolophonidae. ''Barasaurus'' forms the sister taxon to the clade containing ''Saurodektes'' and the only known owenettid older than ''Barasaurus'', ''Owenetta rubidgei'', while ''"Owenetta" kitchingorum'' and ''Candelaria'' form another lineage within the family.<ref name=Candelaria>{{Cite journal | last1 = Cisneros | first1 = J. C. | last2 = Damiani | first2 = R. | last3 = Schultz | first3 = C. | last4 = Da Rosa | first4 = A. | last5 = Schwanke | first5 = C. | last6 = Neto | first6 = L. W. | last7 = Aurelio | first7 = P. L. P. | doi = 10.1098/rspb.2004.2748 | title = A procolophonoid reptile with temporal fenestration from the Middle Triassic of Brazil | journal = Proceedings of the Royal Society B: Biological Sciences | volume = 271 | issue = 1547 | pages = 1541–6 | year = 2004 | pmid = 15306328| pmc = 1691751}}</ref><ref name=RCLTM11>{{Cite journal | last1 = Ruta | first1 = M. | last2 = Cisneros | first2 = J. C. | last3 = Liebrecht | first3 = T. | last4 = Tsuji | first4 = L. A. | last5 = Müller | first5 = J. | title = Amniotes through major biological crises: Faunal turnover among Parareptiles and the end-Permian mass extinction | doi = 10.1111/j.1475-4983.2011.01051.x | journal = Palaeontology | volume = 54 | issue = 5 | pages = 1117 | year = 2011 | doi-access = free }}</ref> The addition of ''Ruhuhuaria'' to the phylogenetic analysis resulted in less resolved relation within Owenettidae, however ''Barasaurus'' and ''Owenetta rubidgei'' are recovered as sister taxa.<ref name=Ruhuhuaria>{{Cite journal | last1 = Tsuji | first1 = L. A. | last2 = Sobral | first2 = G. | last3 = Müller | first3 = J. | doi = 10.1016/j.crpv.2013.08.002 | title = ''Ruhuhuaria reiszi'', a new procolophonoid reptile from the Triassic Ruhuhu Basin of Tanzania | journal = Comptes Rendus Palevol | year = 2013 | volume = 12 | issue = 7–8 | pages = 487–494 }}</ref>
==References== {{Reflist|2}} {{Portal|Paleontology}}
{{Parareptilia|Procolophonoidea}} {{Taxonbar|from=Q16748765}}
Category:Fossil taxa described in 1955 Category:Owenettidae Category:Lopingian reptiles of Africa Category:Early Triassic reptiles of Africa Category:Triassic parareptiles Category:Prehistoric reptile genera