View source for Owenetta

{{Short description|Extinct genus of reptiles}}
{{Automatic taxobox
| fossil_range = {{fossilrange|260.5|250}} <small>Mid [[Wuchiapingian]] - early [[Induan]]</small>
| image = "Owenetta" kitchingorum.jpg
| image_caption = ''"Owenetta" kitchingorum''
| taxon = Owenetta
| authority = [[Robert Broom|Broom]], [[1939 in paleontology|1939]]
| type_species = {{extinct}}'''''Owenetta rubidgei'''''
| type_species_authority = Broom, 1939
| synonyms =
*?''Colubrifer'' <small>Carroll, 1982</small>
*?''Colubrifer campi'' <small>Carroll, 1982</small>
}}
'''''Owenetta''''' is an [[extinct]] [[genus]] of [[owenettid]] [[procolophonia]]n [[parareptile]]. [[Fossil]]s have been found from the [[Beaufort Group]] in the [[Karoo|Karoo Basin]] of [[South Africa]]. Although most procolophonians lived during the [[Triassic]], ''Owenetta'' existed during the [[Wuchiapingian]] and [[Changhsingian]] stages of the [[Permian|Late Permian]] as well as the early [[Induan]] stage of the [[Early Triassic]]. It is the [[type genus]] of the [[family (biology)|family]] [[Owenettidae]], and can be distinguished from other related taxa in that the posterior portion of the supratemporal bears a lateral notch and that the pineal foramen is surrounded by a depressed [[Parietal bone|parietal]] surface on the skull table.
==Species==
The [[type species]] of ''Owenetta'' is ''O. rubidgei''. It is known from  several skulls, but no postcranial skeleton. It was described in 1939 from a partial skull found from the Late Permian [[Cistecephalus Assemblage Zone]] of the Beaufort Group.<ref>Broom, R. (1939). A new type of cotylosaurian, ''Owenetta rubidgei''. ''Annals of the Transvaal Museum'' '''19''':319–321.</ref> Several other localities, all from the overlying [[Dicynodon Assemblage Zone]], have yielded the remainder of the known specimens.
The naming of a new species in 2002, ''O. kitchingorum'', extended the temporal range of ''Owenetta'' into the Early Triassic, meaning that the genus had survived past the [[Permian–Triassic extinction event]].<ref>Reisz, R. R. and Scott, D. (2002). ''Owenetta kitchingorum'', sp. nov., a small parareptile (Procolophonia: Owenettidae) from the Lower Triassic of South Africa. ''Journal of Vertebrate Paleontology'' '''22'''(2):244-256.</ref> This new species was considered distinct from the type species based on features found from three nearly complete specimens that were present from the [[Lystrosaurus Assemblage Zone]]. Found in 1968, the first material of ''O. kitchingorum'' was a small block containing two skeletons in close proximity to one another (although at the time they were thought to be of the type species).<ref>Gow, C. E. (1977). ''Owenetta'' in perspective. ''Palaeontologica Africana'' '''20''':115–118.</ref> These skeletons provided much of the information used to distinguish ''O. kitchingorum'' from the type species. ''O. kitchingorum'' differed from ''O. rubidgei'' in that it possessed small postparietals on the posterior edge of the skull table and that the [[maxilla]] held no more than 20 teeth, some of which were caniniform. The best preserved specimen seems to be a subadult individual on the basis of features of the skull table.
A year after the new species of ''Owenetta'' was named, a paper proposed that it should be assigned to its own distinct genus, although a new name is yet to be provided.<ref>Modesto, S. P., Damiani, R. J.,  Neveling, J. and Yates, A. M. (2003). A new Triassic owenettid parareptile and the Mother of Mass Extinctions. ''Journal of Vertebrate Paleontology'' '''23'''(3):715–719.</ref> A more recent paper also supported this [[polyphyly]].<ref>Modesto, S. P. and Damiani, R. (2007). The Procolophonoid Reptile ''Sauropareion anoplus'' from the Lowermost Triassic of South Africa. ''Journal of Vertebrate Paleontology'' '''27'''(2):337-349</ref> If this is the case, ''Owenetta'' is once again temporally restricted to the late Permian, and most likely died out at the end of the period as a result of the mass extinction event.
Later that year ''[[Colubrifer]]'', named in 1982 from a specimen (UCMP 42773) found from the Early Triassic ''Lystrosaurus'' Assemblage Zone and thought to represent a short limbed [[lizard]], was re-described. Based on a skull nearly identical to those known of ''Owenetta'', it appears that the animal was a procolophonian almost certainly of that genus. It was found to be a [[junior synonym]] of ''Owenetta'', but due to the poor preservation of its holotype, was reassigned ''Owenetta sp''.<ref name=ColubriferRev>{{Cite journal | last1 = Evans | first1 = S. E. | title = The Early Triassic 'lizard' Colubrifer Campi: A Reassessment | doi = 10.1111/1475-4983.00214 | journal = Palaeontology | volume = 44 | issue = 5 | pages = 1033–1041 | year = 2001 | doi-access = free | bibcode = 2001Palgy..44.1033E }}</ref>
==Phylogenetics==
When ''Owenetta'' was first named and described, it and other procolophonians were thought to be within Cotylosauria, a group that comprised what was believed to be the most primitive of reptiles. Cotylosauria has since been renamed [[Captorhinida]], which is now thought to be a [[paraphyletic]] group [[anapsid]]s and anapsid relatives. ''Owenetta'' and other procolophonians are now known to be within the [[Class (biology)|subclass]] Parareptilia. It has later been placed within the family [[Nyctiphruretidae]], but is currently placed within the family Owenettidae, of which it is the type genus.<ref>Lee, M. S. Y. (1995). Historical burden in systematics and the interrelationships of parareptiles. ''Biological Reviews'' '''70'''(3):459-547.</ref><ref>deBraga, M. and Reisz, R. (1996). The [[Cisuralian|Early Permian]] reptile ''Acleistorhinus pteroticus'' and its phylogenetic position. ''Journal of Vertebrate Paleontology'' '''16'''(3):384-395</ref><ref>Säilä, L. K. (2008). The osteology and affinities of ''Anomoiodon liliensterni'', a procolophonid reptile from the Lower Triassic Buntsandstein of Germany. ''Journal of Vertebrate Paleontology'' '''28'''(4):1199-1205</ref>
The well preserved, nearly complete specimens of ''Owenetta'' can be helpful in phylogenetic analyses of procolophonians and the parareptiles, which have recently undergone many great revisions. Although the postcranial skeleton is only known from immature individuals, comparisons can be made with related taxa such as ''[[Barasaurus]]'', which is known from both immature and mature specimens, that resolve this morphology issue. ''Owenetta'' has been used in some phylogenetic analyses to uphold the traditional theory that the procolophonians were the ancestors of [[turtle]]s,<ref>Reisz, R. R. and Laurin, M. (1991). ''Owenetta'' and the origin of turtles. ''Nature'' '''349''':324-326.</ref> although it now seems that turtles, if not [[Archosauromorpha]], have evolved from [[pareiasauridae|parieasaurids]]<ref>Lee, M. S. Y. (1997). Pareiasaur phylogeny and the origin of turtles. ''Zoological Journal of the Linnean Society'' '''120''':197-280</ref> or even [[sauropterygia]]ns.<ref>Rieppel, O. and deBraga, M. (1996). Turtles as diapsid reptiles. ''Nature'' '''384''':453-455.</ref>
==References==
{{Reflist}}
==External links==
*[https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=37521 ''Owenetta''] in the [[Paleobiology Database]]
{{portal|Paleontology}}
{{Parareptilia|Procolophonoidea}}
{{Taxonbar|from=Q2908639}}
[[Category:Owenettids]]
[[Category:Lopingian reptiles of Africa]]
[[Category:Early Triassic reptiles of Africa]]
[[Category:Lopingian first appearances]]
[[Category:Wuchiapingian life]]
[[Category:Changhsingian life]]
[[Category:Induan life]]
[[Category:Early Triassic extinctions]]
[[Category:Prehistoric reptile genera]]