Rubidgea

{{Short description|Extinct genus of therapsids}} {{Automatic taxobox | fossil_range = Late Permian (Wuchiapingian to Changhsingian), {{fossilrange|257|253}} {{period fossil range|Permian|257|253}} | image = Rubidgea.JPG | image_caption = Skull of ''Rubidgea atrox'' | taxon = Rubidgea | subdivision_ranks = Species | subdivision = | authority = | type_species = {{extinct}}'''''Rubidgea atrox''''' | type_species_authority = Broom, 1938 | synonyms = '''Genus-level''' * ''Broomicephalus'' Brink & Kitching, 1953 * ''Titanogorgon'' Maisch, 2002 '''Species-level''' * ''Rubidgea kitchingi'' Broom, 1938 * ''Rubidgea laticeps'' Broom, 1940 * ''Gorgonognathus maximus'' Huene, 1950 * ''Broomicephalus laticeps'' Brink & Kitching, 1953 * ''Rubidgea majora'' Brink & Kitching, 1953 * ''Dinogorgon (Broomicephalus) laticeps'' Watson & Romer, 1956 * ''Titanogorgon maximus'' Maisch, 2002 * ''Clelandina laticeps'' Gebauer, 2007 *''Rubidgea platyrhina'' }}

'''''Rubidgea''''' is a genus of gorgonopsian from the upper Permian of South Africa and Tanzania, containing only one species, '''''Rubidgea atrox'''''.<ref>{{Cite journal|last1=Rubidge|first1=Bruce S.|last2=Sidor|first2=Christian A.|date=2001|title=Evolutionary Patterns Among Permo-Triassic Therapsids|journal=Annual Review of Ecology and Systematics|volume=32|issue=1|pages=449–480|doi=10.1146/annurev.ecolsys.32.081501.114113 |bibcode=2001AnRES..32..449R }}</ref><ref>{{Cite book|url=https://books.google.com/books?id=cp26-CA2CDUC&q=++Chinsamy-Turan,+A.+ed.,+2011.+Forerunners+of+Mammals:+Radiation%E2%80%A2+Histology%E2%80%A2+Biology.+Indiana+University+Press.&pg=PR7|title=Forerunners of Mammals: Radiation • Histology • Biology|last=CHINSAMY-TURAN|first=ANUSUYA|date=2011-11-18|publisher=Indiana University Press|isbn=978-0-253-00533-5|language=en}}</ref><ref name="Kammerer2016">{{Cite journal|last=Kammerer|first=Christian F.|date=2016-01-26|title=Systematics of the Rubidgeinae (Therapsida: Gorgonopsia)|journal=PeerJ|language=en|volume=4|article-number=e1608|doi=10.7717/peerj.1608|pmid=26823998|issn=2167-8359|pmc=4730894 |doi-access=free }}</ref> The generic name ''Rubidgea'' honours fossil hunter Sidney Rubidge. Its species name, ''atrox'', is derived from Latin, meaning "fierce, savage, terrible". ''Rubidgea'' is part of the gorgonopsian subfamily Rubidgeinae, a derived group of large-bodied gorgonopsians restricted to the Late Permian (Lopingian).<ref>{{Cite book|last=Lingham-Soliar|first=Theagarten|chapter=Mammal-Like Reptiles|date=2014|title=The Vertebrate Integument Volume 1: Origin and Evolution|pages=193–219|editor-last=Lingham-Soliar|editor-first=Theagarten|publisher=Springer Berlin Heidelberg|language=en|doi=10.1007/978-3-642-53748-6_8|isbn=978-3-642-53748-6}}</ref><ref>{{Cite journal|last1=Day Michael O.|last2=Ramezani Jahandar|last3=Bowring Samuel A.|last4=Sadler Peter M.|last5=Erwin Douglas H.|last6=Abdala Fernando|last7=Rubidge Bruce S.|date=2015-07-22|title=When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa|journal= Proceedings of the Royal Society B: Biological Sciences|volume=282|issue=1811|article-number=20150834|doi=10.1098/rspb.2015.0834|pmc=4528552|pmid=26156768 |bibcode=2015RSPSB.28250834D }}</ref><ref>{{Cite journal |title=The ''Daptocephalus'' Assemblage Zone (Lopingian), South Africa: a proposed biostratigraphy based on a new compilation of stratigraphic ranges |journal=Journal of African Earth Sciences |volume=113 |pages=153–164 |author=Viglietti, P.A. |author2=Smith, R.M. |author3=Angielczyk, K.D. |author4=Kammerer, C.F. |author5=Fröbisch, J. |author6=Rubidge, B.S. |date=January 2016 |doi=10.1016/j.jafrearsci.2015.10.011|bibcode = 2016JAfES.113..153V}}</ref>

==Taxonomy==

=== Discovery === The first ''Rubidgea'' fossil was discovered by C. J. M. "Croonie" Kitching, the father of renowned paleontologist James Kitching, on the farm Doornberg outside the small town Nieu-Bethesda during the early 1930s. In a paper published in 1938, Robert Broom named the fossil ''Rubidgea kitchingi''.<ref>Broom, Robert. "20. On a New Family of Carnivorous Therapsids from the Karroo Beds of South Africa." In Proceedings of the Zoological Society of London, vol. 108, no. 3, pp. 527-533. Oxford, UK: Blackwell Publishing Ltd, 1938.</ref> Broom noted the large size of the new gorgonopsid fossil, stating that it was a new species.<ref>{{Cite journal|last=Kitching|first=J. W.|date=1953|title=Studies on new specimens of the Gorgonopsia|journal=Palaeontologia Africana|url=http://wiredspace.wits.ac.za/handle/10539/14667|language=en}}</ref> Subsequent discoveries in the following decades confirmed Broom's suspicions that a new subfamily of gorgonopsians should be categorised, and the Rubidgeinae was erected.<ref>{{Cite journal|last=Cruickshank|first=A. R. I.|date=1973|title=THE MODE OF LIFE OF GORGONOPSIANS|journal=Palaeontologia Africana|url=http://wiredspace.wits.ac.za/handle/10539/16039|language=en|issn=0078-8554}}</ref>

=== Classification === [[File:Rubidgea atrox.png|thumb|Holotype skull]] The Rubidgeinae are a subfamily of derived gorgonopsians that have only been found in Africa. They are composed of six genera and 17 species. The Rubidgeinae are closely related to their sister group, the Inostranceviinae, which have only been found in Russia. Out of the gorgonopsian clade, the systematics of the Rubidgeinae is the best resolved due to their distinctive character traits. The systematics of other gorgonopsian subfamilies remain chaotic due to a high degree of cranial homomorphism between taxa, making it difficult to distinguish different taxa effectively.<ref>{{Cite journal|last1=Kemp T. S.|last2=Parrington Francis Rex|s2cid=58926603|date=1969-09-04|title=On the functional morphology of the gorgonopsid skull|journal= Philosophical Transactions of the Royal Society B: Biological Sciences|volume=256|issue=801|pages=1–83|doi=10.1098/rstb.1969.0036|bibcode=1969RSPTB.256....1K|doi-access=free}}</ref><ref>{{Cite journal|last=Sigogneau|first=D.|date=1968|title=On the classification of the Gorgonopsia|journal=Palaeontologia Africana|url=http://wiredspace.wits.ac.za/handle/10539/16116|language=en|issn=0078-8554}}</ref><ref>Sigogneau-Russell, D., 1989. Theriodontia 1: Phthinosuchia, Eotitanosuchia, Gorgonopsia.</ref><ref>{{Cite journal|last1=Martins|first1=Rui M. S.|last2=Fröbisch|first2=Jörg|last3=Polcyn|first3=Michael J.|last4=Fernandez|first4=Vincent|last5=Araujo|first5=Ricardo M.|date=2017-02-21|title=Aspects of gorgonopsian paleobiology and evolution: insights from the basicranium, occiput, osseous labyrinth, vasculature, and neuroanatomy|journal=PeerJ|volume=5|article-number=e3119|language=en|doi=10.7717/peerj.3119|pmid=28413721|pmc=5390774 |doi-access=free }}</ref><ref>{{Cite thesis|title=Relative growth and morphological variation in the skull of Aelurognathus (therapsida: gorgonopsia)|url=http://wiredspace.wits.ac.za/handle/10539/12361|date=2013-02-01|language=en|first=Luke Allan|last=Norton}}</ref><ref>{{Citation|last=Gebauer|first=Eva V. I.|chapter=Re-assessment of the Taxonomic Position of the Specimen GPIT/RE/7113 (''Sauroctonus parringtoni'' comb. Nov., Gorgonopsia) |date=2014|pages=185–207|editor-last=Kammerer|editor-first=Christian F.|series=Vertebrate Paleobiology and Paleoanthropology|publisher=Springer Netherlands|language=en|doi=10.1007/978-94-007-6841-3_12|isbn=978-94-007-6841-3|editor2-last=Angielczyk|editor2-first=Kenneth D.|editor3-last=Fröbisch|editor3-first=Jörg|title=Early Evolutionary History of the Synapsida}}</ref><ref>{{Citation|last=Kammerer|first=Christian F.|chapter=A Redescription of ''Eriphostoma microdon'' Broom, 1911 (Therapsida, Gorgonopsia) from the ''Tapinocephalus'' Assemblage Zone of South Africa and a Review of Middle Permian Gorgonopsians |date=2014|pages=171–184|editor-last=Kammerer|editor-first=Christian F.|series=Vertebrate Paleobiology and Paleoanthropology|publisher=Springer Netherlands|language=en|doi=10.1007/978-94-007-6841-3_11|isbn=978-94-007-6841-3|editor2-last=Angielczyk|editor2-first=Kenneth D.|editor3-last=Fröbisch|editor3-first=Jörg|title=Early Evolutionary History of the Synapsida}}</ref><ref>{{Cite journal|last=Kammerer|first=Christian F.|date=2015|title=Cranial osteology of ''Arctognathus curvimola'', a short-snouted gorgonopsian from the Late Permian of South Africa|journal=Papers in Palaeontology|language=en|volume=1|issue=1|pages=41–58|doi=10.1002/spp2.1002|bibcode=2015PPal....1...41K |issn=2056-2802|doi-access=free}}</ref><ref>{{Cite journal|last1=Kammerer|first1=Christian F.|last2=Smith|first2=Roger M. H.|last3=Day|first3=Michael O.|last4=Rubidge|first4=Bruce S.|date=2015|title=New information on the morphology and stratigraphic range of the mid-Permian gorgonopsian ''Eriphostoma microdon'' Broom, 1911|journal=Papers in Palaeontology|language=en|volume=1|issue=2|pages=201–221|doi=10.1002/spp2.1012|bibcode=2015PPal....1..201K |s2cid=128762256 |issn=2056-2802}}</ref><ref>{{Cite journal|last1=Fröbisch|first1=Jörg|last2=Fernandez|first2=Vincent|last3=Kardjilov|first3=Nikolay|last4=Kammerer|first4=Christian F.|last5=Bendel|first5=Eva-Maria|date=2018-11-28|title=Cranial anatomy of the gorgonopsian ''Cynariops robustus'' based on CT-reconstruction|journal=PLOS ONE|language=en|volume=13|issue=11|article-number=e0207367|doi=10.1371/journal.pone.0207367|issn=1932-6203|pmc=6261584|pmid=30485338|bibcode=2018PLoSO..1307367B|doi-access=free}}</ref> The cladogram below (Kammerer and Rubidge 2022) displays the currently accepted systematic relationships of the Gorgonopsia.<ref>{{Cite journal|last1=Kammerer |first1=C. F. |last2=Rubidge |first2=B. S. |year=2022 |title=The earliest gorgonopsians from the Karoo Basin of South Africa |journal=Journal of African Earth Sciences |volume=194 |article-number=104631 |doi=10.1016/j.jafrearsci.2022.104631|bibcode=2022JAfES.19404631K |s2cid=249977414 }}</ref>

{{clade|style=font-size:100%;line-height:85% |label1 = Gorgonopsia |1={{clade |1=''Nochnitsa'' |2={{clade |1=''Viatkogorgon'' |2={{clade |label1="Russian clade" |1={{clade |1=''Suchogorgon'' |2={{clade |1=''Sauroctonus'' |2={{clade |1=''Pravoslavlevia'' |2=''Inostrancevia'' }} }} }} |label2="African clade" |2={{clade |1=''Phorcys'' |2=''Eriphostoma'' |3=''Gorgonops'' |4={{clade |1 =''Cynariops'' |2={{clade |1=''Lycaenops'' |2={{clade |1=''Smilesaurus'' |2=''Arctops'' }} |label3=Rubidgeinae |3={{clade |1=''Arctognathus'' |2={{clade |1=''Aelurognathus'' |2={{clade |1=''Ruhuhucerberus'' |2={{clade |1=''Sycosaurus'' |label2=Rubidgeini |2={{clade |1=''Leontosaurus'' |2={{clade |1=''Dinogorgon'' |2={{clade |1=''Clelandina'' |2='''''Rubidgea''''' }} }} }} }} }} }} }} }} }} }} }} }} }} }}

==Description== thumb|left|Restoration ''Rubidgea'' was the largest African gorgonopsian and one of the largest gorgonopsians known to have lived.<ref name="Kammerer2016" /> The largest specimens had skulls that measure up to {{cvt|45|cm|ft}} in length. It has been estimated at {{convert|3|m|ft}} in length.<ref>{{Cite book |last=Antón |first=Mauricio |url=https://books.google.com/books?id=dVcqAAAAQBAJ&q=rubidgea |title=Sabertooth |date=2021-12-22 |publisher=Indiana University Press |isbn=978-0-253-01049-0 |language=en}}</ref><ref name="Kammerer2016" /> ''Rubidgea'' was a heavily-built, large-bodied apex predator, and sported a thick skull with long, sabre-like canines.<ref>{{Cite journal|last1=Jenkins|first1=Ian|last2=Valkenburgh|first2=Blaire Van|date=2002-10-01|title=Evolutionary Patterns in the History of Permo-Triassic and Cenozoic Synapsid Predators|journal=The Paleontological Society Papers|language=en|volume=8|pages=267–288|doi=10.1017/S1089332600001121|issn=1089-3326}}</ref><ref>{{Citation|last1=Kermack|first1=Doris M.|title=Dentitions, Tooth-Replacement and Jaw Articulation|date=1984|work=The Evolution of Mammalian Characters|pages=66–88|editor-last=Kermack|editor-first=Doris M.|publisher=Springer US|language=en|doi=10.1007/978-1-4684-7817-4_5|isbn=978-1-4684-7817-4|last2=Kermack|first2=Kenneth A.|editor2-last=Kermack|editor2-first=Kenneth A.}}</ref> The Rubidgeinae group as a whole were some of the largest gorgonopsians known to have lived, only outsized by ''Inostrancevia'', and are characterised by their robust skeletal features, particularly their skulls which are heavily-pachyostosed.<ref name=Kammerer2016/>

==Correlation==

Numerous therapsid species, including rubidgenae gorgonopsids, are used as biostratigraphic markers in other African Basins, such as the Upper Madumabisa Mudstone Formation of Zambia, and the Chiweta Beds of Malawi.<ref>Maisch, M.W., 2002. Observations on Karoo and Gondwana vertebrates. Part 3: Notes on the gorgonopsians from the Upper Permian of Tanzania. Neues Jahrbuch fur Geologie und Palaontologie-Monatshefte, (4), pp.237-251.</ref> ''Rubidgea'' fossils have been recovered from the Usili Formation of Tanzania, indicating biostratigraphic correlation with upper Permian-aged deposits in South Africa.<ref>Parrington, F. R. "A new genus of gorgonopsid from East Africa." Annals of the South African Museum 64 (1974): 47-52.</ref> No rubidgeinae fossils have been found outside of African deposits to date, although the Inostranceviinae are considered to be their Russian counterparts. In 2023, fossils of ''Inostrancevia'' were described from South Africa, dating to the onset of the Permian–Triassic extinction event. The same paper found no evidence for the survival of ''Rubidgea'' to the P–Tr boundary and concluded the genus went extinct prior to it.<ref>{{Cite journal |last1=Kammerer |first1=Christian F. |last2=Viglietti |first2=Pia A. |last3=Butler |first3=Elize |last4=Botha |first4=Jennifer |date=2023-06-05 |title=Rapid turnover of top predators in African terrestrial faunas around the Permian-Triassic mass extinction |url=https://www.cell.com/current-biology/abstract/S0960-9822(23)00455-4 |journal=Current Biology |language=English |volume=33 |issue=11 |pages=2283–2290.e3 |doi=10.1016/j.cub.2023.04.007 |issn=0960-9822 |pmid=37220743 |bibcode=2023CBio...33E2283K |url-access=subscription }}</ref> In 2024, fossils of ''Inostrancevia'' were described from the Usili Formation, showing it coexisted with rubidgines before the onset of the end-Permian extinction.<ref>{{Cite journal |last1=Brant |first1=Anna J. |last2=Sidor |first2=Christian A. |date=2023-07-04 |title=Earliest evidence of ''Inostrancevia'' in the southern hemisphere: new data from the Usili Formation of Tanzania |journal=Journal of Vertebrate Paleontology |volume=43 |issue=4 |article-number=e2313622 |doi=10.1080/02724634.2024.2313622 |bibcode=2023JVPal..43E3622B |issn=0272-4634}}</ref><ref>{{Cite journal |last1=Macungo |first1=Zanildo |last2=Benoit |first2=Julien |last3=Araújo |first3=Ricardo |date=2025-03-06 |title=''Inostrancevia africana'', the first diagnosable gorgonopsian (Therapsida, Synapsida) from the Metangula graben (Mozambique): new anatomical observations and biostratigraphic implications |journal=Swiss Journal of Palaeontology |volume=144 |issue=1 |page=12 |doi=10.1186/s13358-025-00348-7 |doi-access=free |issn=1664-2384}}</ref>

==References== {{Reflist}}

Category:Gorgonopsia Category:Prehistoric therapsid genera Category:Permian synapsids of Africa Category:Fossil taxa described in 1938