Rubidgea

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Rubidgea
Temporal range: Permian 257–254  Ma
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Rubidgea.JPG
Skull of Rubidgea atrox
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Clade:† Gorgonopsia
Family:† Gorgonopsidae
Tribe:† Rubidgeini
Genus:† Rubidgea
Type species
†Rubidgea atrox
Broom, 1938
Species
  • †R. atrox
  • †R. platyrhina
  • †R. majora
Synonyms

Genus-level

  • BroomicephalusBrink & Kitching, 1953
  • TitanogorgonMaisch, 2002

Species-level

  • Rubidgea kitchingiBroom, 1938
  • Rubidgea laticepsBroom, 1940
  • Gorgonognathus maximusHuene, 1950
  • Broomicephalus laticepsBrink & Kitching, 1953
  • Rubidgea majoraBrink & Kitching, 1953
  • Dinogorgon (Broomicephalus) laticepsWatson & Romer, 1956
  • Titanogorgon maximusMaisch, 2002
  • Clelandina laticepsGebauer, 2007

Rubidgea is a genus of gorgonopsian from the upper Permian of South Africa and Tanzania, containing the species Rubidgea atrox. [1] [2] The generic name Rubidgea is sometimes believed to be derived from the surname of renowned Karoo paleontologist, Professor Bruce Rubidge, who has contributed to much of the research conducted on therapsids of the Karoo Basin. However, this generic name was actually erected in honor of Rubidge's paternal grandfather, Sidney Rubidge, who was a renowned fossil hunter. 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). The subfamily Rubidgeinae first appeared in the Tropidostoma Assemblage Zone. They reached their highest diversity in the Cistecephalus and Daptocephalus assemblage zones of the Beaufort Group in South Africa. [3] [4] [5]

Contents

History of 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 sometime in the 1930s. In a paper published in 1938, Robert Broom named the fossil Rubidgea kitchingi. [6] Broom noted the large size of the new gorgonopsid fossil, stating that it was a new species. [7] Subsequent discoveries in the following decades confirmed Broom's suspicions that a new subfamily of gorgonopsians should be categorised, and the Rubidgeinae was erected. [8]

Description

Restoration Broomicephalus1DB.jpg
Restoration

Rubidgea was the largest African gorgonopsian [9] and one of the largest gorgonopsians known to have lived. The largest specimens had skulls that measure up to 46 cm (1.51 ft) in length. Rubidgea was a heavily-built, large-bodied apex predator, and sported a thick skull with long, sabre-like canines. [10] [11] 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. The genus Rubidgea is composed of three species, R. atrox, R. platyrhina, and R. majora. [9]


Classification

Holotype skull Rubidgea atrox.png
Holotype skull

The Rubidgeinae are a subfamily of derived gorgonopsids 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. [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] The cladogram below (Kammerer and Rubidge 2022) displays the currently accepted systematic relationships of the Gorgonopsia. [22]

Gorgonopsia

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. [23] Rubidgea fossils have been recovered from the Usili Formation of Tanzania, indicating biostratigraphic correlation with upper Permian-aged deposits in South Africa. [24] No rubidgeinae fossils have been found outside of African deposits to date, although the Inostranceviinae are considered to be their Russian counterparts.

Related Research Articles

<span class="mw-page-title-main">Gorgonopsia</span> Extinct group of saber-toothed therapsids from the Permian

Gorgonopsia is an extinct clade of sabre-toothed therapsids from the Middle to the Upper Permian, roughly between 265 and 252 million years ago. They are characterised by a long and narrow skull, as well as elongated upper and sometimes lower canine teeth and incisors which were likely used as slashing and stabbing weapons. Postcanine teeth are generally reduced or absent. For hunting large prey, they possibly used a bite-and-retreat tactic, ambushing and taking a debilitating bite out of the target, and following it at a safe distance before its injuries exhausted it, whereupon the gorgonopsian would grapple the animal and deliver a killing bite. They would have had an exorbitant gape, possibly in excess of 90°, without having to unhinge the jaw.

<i>Inostrancevia</i> Extinct genus of therapsids

Inostrancevia is an extinct genus of large carnivorous therapsids which lived during the Late Permian in what are now Siberia, Russia and Southern Africa. The first-known fossils of this gorgonopsian were discovered in the Northern Dvina, where two almost complete skeletons were exhumed. Subsequently, several other fossil materials were discovered in various oblasts, and these finds will lead to a confusion about the exact number of valid species in the country, before only three of them were officially recognized: I. alexandri, I. latifrons and I. uralensis. More recent research carried out in South Africa has discovered fairly well-preserved remains of the genus, being attributed to the species I. africana. An isolated left premaxilla suggests that Inostrancevia also lived in Tanzania during the earliest Lopingian age. The whole genus is named in honor of Alexander Inostrantsev, professor of Vladimir P. Amalitsky, the paleontologist who described the taxon.

<i>Emydops</i> Extinct genus of dicynodonts

Emydops is an extinct genus of dicynodont therapsids from the Middle Permian to Late Permian of what is now South Africa. The genus is generally small and herbivorous, sharing the dicynodont synapomorphy of bearing two tusks. In the following years, the genus grew to include fourteen species. Many of these species were erected on the basis of differences in the teeth and the positioning of the frontal and parietal bones. A 2008 study narrowed Emydops down to two species, E. arctatus and the newly described E. oweni.

<i>Dinogorgon</i> Extinct genus of therapsids

Dinogorgon is a genus of gorgonopsid from the Late Permian of South Africa and Tanzania. The generic name Dinogorgon is derived from Greek, meaning "terrible gorgon", while its species name rubidgei is taken from the surname of renowned Karoo paleontologist, Professor Bruce Rubidge, who has contributed to much of the research conducted on therapsids of the Karoo Basin. The type species of the genus is D. rubidgei.

<i>Tapinocephalus</i> Assemblage Zone

The Tapinocephalus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the middle Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 2,000 metres (6,600 ft), occur from Merweville and Leeu-Gamka in its southernmost exposures, from Sutherland through to Beaufort West where outcrops start to only be found in the south-east, north of Oudshoorn and Willowmore, reaching up to areas south of Graaff-Reinet. Its northernmost exposures occur around the towns Fraserburg and Victoria West. The Tapinocephalus Assemblage Zone is the second biozone of the Beaufort Group.

<i>Daptocephalus</i> Assemblage Zone Biozone of fossils

The Daptocephalus Assemblage Zone is a tetrapod assemblage zone or biozone found in the Adelaide Subgroup of the Beaufort Group, a majorly fossiliferous and geologically important Group of the Karoo Supergroup in South Africa. This biozone has outcrops located in the upper Teekloof Formation west of 24°E, the majority of the Balfour Formation east of 24°E, and the Normandien Formation in the north. It has numerous localities which are spread out from Colesberg in the Northern Cape, Graaff-Reniet to Mthatha in the Eastern Cape, and from Bloemfontein to Harrismith in the Free State. The Daptocephalus Assemblage Zone is one of eight biozones found in the Beaufort Group and is considered Late Permian (Lopingian) in age. Its contact with the overlying Lystrosaurus Assemblage Zone marks the Permian-Triassic boundary.

<i>Tropidostoma</i> Assemblage Zone

The Tropidostoma Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the lower Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 240 metres (790 ft), occur from east of Sutherland through to Beaufort West and Victoria West, to areas south of Graaff-Reinet. Its northernmost exposures occur west/north-west of Colesberg. The Tropidostoma Assemblage Zone is the fourth biozone of the Beaufort Group.

<i>Sauroctonus</i> Extinct genus of therapsids

Sauroctonus is an extinct genus of gorgonopsian therapsids who lived during the end of the Middle Permian in what is now European Russia. The first fossils, discovered in Tatarstan, were initially believed to belong to a new species of the South African genus Arctognathus. The taxon was designated as such until 1940, when it was assigned to the genus Inostrancevia by Ivan Yefremov, before being definitively classified in a separate genus erected by Alexey Bystrow. The most complete, known fossils of S. progressus include cranial and postcranial elements, currently all recorded from Tatarstan. These elements show that the animal was a mid-sized gorgonopsian.

<i>Aelurognathus</i> Extinct genus of therapsids

Aelurognathus is an extinct genus of gorgonopsian therapsids from the Permian of South Africa and Zambia.

<i>Lemurosaurus</i> Extinct genus of therapsids

Lemurosaurus is a genus of extinct biarmosuchian therapsids from the Late Permian of South Africa. The generic epithet Lemursaurus is a mix of Latin, lemures “ghosts, spirits”, and Greek, sauros, “lizard”. Lemurosaurus is easily identifiable by its prominent eye crests, and large eyes. The name Lemurosaurus pricei was coined by paleontologist Robert Broom in 1949, based on a single small crushed skull, measured at approximately 86 millimeters in length, found on the Dorsfontein farm in Graaff-Reinet. To date, only two skulls of the Lemurosaurus have been discovered, so body size is unknown. The second larger, more intact, skull was found in 1974 by a team from the National Museum, Bloemfontein.

<i>Clelandina</i> Extinct genus of therapsids

Clelandina is an extinct genus of rubidgeine gorgonopsian from the Late Permian of Cistecephalus Assemblage Zone of South Africa. It was first named by Broom in 1948. The type and only species is C. rubidgei. It is relatively rare, with only four known specimens.

<i>Scylacops</i> Extinct genus of therapsids

Scylacops is an extinct genus of Gorgonopsia. It was first named by Broom in 1913, and contains two species, S. bigendens, and S. capensis. Its fossils have been found in South Africa and Zambia. It is believed to be closely related to the Gorgonopsian Sauroctonus progressus. Scylacops was a moderately sized Gorgonopsid.

<i>Eriphostoma</i> Extinct genus of therapsids

Eriphostoma is an extinct genus of gorgonopsian therapsids known from the Middle Permian of Tapinocephalus Assemblage Zone, South Africa. It has one known species, Eriphostoma microdon, and was first named by Robert Broom in 1911. It is the oldest known gorgonopsian and among the smallest and most basal members of the clade.

<i>Tropidostoma</i> Extinct genus of dicynodonts

Tropidostoma is a medium-sized herbivorous oudenodontid dicynodont therapsid that lived during the Late Permian (Lopingian) period in South Africa. The first Tropidostoma fossil was described by Harry Govier Seeley in 1889. Later two subspecies were identified. Tropidostoma fossils are an index fossil in a biozone of the Karoo Basin known as the Tropidostoma Assemblage Zone. This biozone is characterized by the presence of this species in association with another dicynodont species, Endothiodon uniseries.

<i>Smilesaurus</i> Extinct genus of therapsids

Smilesaurus is an extinct genus of gorgonopsian known from South Africa. It lived during the Late Permian. It contains the single species S. ferox.

<i>Ruhuhucerberus</i> Extinct genus of therapsids

Ruhuhucerberus is a genus of very large, extinct gorgonopsian therapsids which existed in Tanzania during the Late Permian. Its fossils are found in the Penman Kawinga Formation of the Ruhuhu Basin. It existed sympatrically with the even larger Rubidgea.

"Dixeya" nasuta is a extinct species of gorgonopsian that lived during the Late Permian of East Africa, known from fossils found in what is now Tanzania. The species has a complicated taxonomic history, it was originally named as a second species of the genus Dixeya which is now considered a junior synonym of Aelurognathus. "D." nasuta itself, however, was not moved to Aelurognathus, and although it was instead tentatively referred to Arctognathus at first it has since been recognised to not belong to this genus either. This situation leaves "Dixeya" nasuta without a formal genus name. It was proposed to belong to a new distinct genus, named "Njalila", that was informally proposed for the species in a PhD thesis, but this name has not yet been formally published and is currently a nomen nudum. "D." nasuta has been characterised from other gorgonopsians by a combination of its straight snout profile, upturned and "pinched" nose, and curved jaw margin. The fossil record of the Usili Formation shows that the taxon was contemporary with many other gorgonopsians, even alongside large representatives such as Inostrancevia and rubidgeines.

<span class="mw-page-title-main">Rubidgeinae</span> Extinct subfamily of mammals

Rubidgeinae is an extinct subfamily of gorgonopsid therapsids known only from Africa. They were among the largest gorgonopsians, and their fossils are common in the Cistecephalus and Daptocephalus assemblage zones of the Karoo Basin. They lived during the Late Permian, and became extinct at the end of the Permian.

<span class="mw-page-title-main">Balfour Formation</span> Geological formation in the Beaufort Group of South Africa

The Balfour Formation is a geological formation that is found in the Beaufort Group, a major geological group that forms part of the greater Karoo Supergroup in South Africa. The Balfour Formation is the uppermost formation of the Adelaide Subgroup which contains all the Late Permian - Early Triassic aged biozones of the Beaufort Group. Outcrops and exposures of the Balfour Formation are found from east of 24 degrees in the highest mountainous escarpments between Beaufort West and Fraserburg, but most notably in the Winterberg and Sneeuberg mountain ranges near Cradock, the Baviaanskloof river valley, Graaff-Reniet and Nieu Bethesda in the Eastern Cape, and in the southern Free State province.

Phorcys is an extinct genus of gorgonopsian that lived during the Middle Permian period (Guadalupian) of what is now South Africa. It is known from two specimens, both portions from the back of the skull, that were described and named in 2022 as a new genus and species P. dubei by Christian Kammerer and Bruce Rubidge. Phorcys was recovered from the lowest strata of the Tapinocephalus Assemblage Zone (AZ) of the Beaufort Group, making it one of the oldest known gorgonopsians in the fossil record—second only to fragmentary remains of an indeterminate specimen from the older underlying Eodicynodon Assemblage Zone. The generic name is from Phorcys of Greek mythology, the father of the Gorgons from which the gorgonopsians are named after, and refers to its status as one of the oldest representatives of the group.

References

  1. ↑ Rubidge, Bruce S.; Sidor, Christian A. (2001). "Evolutionary Patterns Among Permo-Triassic Therapsids". Annual Review of Ecology and Systematics. 32 (1): 449–480. doi:10.1146/annurev.ecolsys.32.081501.114113.
  2. ↑ CHINSAMY-TURAN, ANUSUYA (2011-11-18). Forerunners of Mammals: Radiation • Histology • Biology. Indiana University Press. ISBN   9780253005335.
  3. ↑ Lingham-Soliar, Theagarten (2014). "Mammal-Like Reptiles". In Lingham-Soliar, Theagarten (ed.). The Vertebrate Integument Volume 1: Origin and Evolution. Springer Berlin Heidelberg. pp. 193–219. doi:10.1007/978-3-642-53748-6_8. ISBN   9783642537486.
  4. ↑ Day Michael O.; Ramezani Jahandar; Bowring Samuel A.; Sadler Peter M.; Erwin Douglas H.; Abdala Fernando; Rubidge Bruce S. (2015-07-22). "When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa". Proceedings of the Royal Society B: Biological Sciences. 282 (1811): 20150834. doi:10.1098/rspb.2015.0834. PMC   4528552 . PMID   26156768.
  5. ↑ Viglietti, P.A.; Smith, R.M.; Angielczyk, K.D.; Kammerer, C.F.; Fröbisch, J.; Rubidge, B.S. (January 2016). "The Daptocephalus Assemblage Zone (Lopingian), South Africa: a proposed biostratigraphy based on a new compilation of stratigraphic ranges". Journal of African Earth Sciences. 113: 153–164. Bibcode:2016JAfES.113..153V. doi:10.1016/j.jafrearsci.2015.10.011.
  6. ↑ 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.
  7. ↑ Kitching, J. W. (1953). "Studies on new specimens of the Gorgonopsia". Palaeontologia Africana.
  8. ↑ Cruickshank, A. R. I. (1973). "THE MODE OF LIFE OF GORGONOPSIANS". Palaeontologia Africana. ISSN   0078-8554.
  9. 1 2 Kammerer, Christian F. (2016-01-26). "Systematics of the Rubidgeinae (Therapsida: Gorgonopsia)". PeerJ. 4: e1608. doi: 10.7717/peerj.1608 . ISSN   2167-8359. PMC   4730894 . PMID   26823998.
  10. ↑ Jenkins, Ian; Valkenburgh, Blaire Van (2002-10-01). "Evolutionary Patterns in the History of Permo-Triassic and Cenozoic Synapsid Predators". The Paleontological Society Papers. 8: 267–288. doi:10.1017/S1089332600001121. ISSN   1089-3326.
  11. ↑ Kermack, Doris M.; Kermack, Kenneth A. (1984), Kermack, Doris M.; Kermack, Kenneth A. (eds.), "Dentitions, Tooth-Replacement and Jaw Articulation", The Evolution of Mammalian Characters, Springer US, pp. 66–88, doi:10.1007/978-1-4684-7817-4_5, ISBN   9781468478174
  12. ↑ Kemp T. S.; Parrington Francis Rex (1969-09-04). "On the functional morphology of the gorgonopsid skull". Philosophical Transactions of the Royal Society B: Biological Sciences. 256 (801): 1–83. Bibcode:1969RSPTB.256....1K. doi: 10.1098/rstb.1969.0036 . S2CID   58926603.
  13. ↑ Sigogneau, D. (1968). "On the classification of the Gorgonopsia". Palaeontologia Africana. ISSN   0078-8554.
  14. ↑ Sigogneau-Russell, D., 1989. Theriodontia 1: Phthinosuchia, Eotitanosuchia, Gorgonopsia.
  15. ↑ Martins, Rui M. S.; Fröbisch, Jörg; Polcyn, Michael J.; Fernandez, Vincent; Araujo, Ricardo M. (2017-02-21). "Aspects of gorgonopsian paleobiology and evolution: insights from the basicranium, occiput, osseous labyrinth, vasculature, and neuroanatomy". PeerJ. 5: e3119. doi: 10.7717/peerj.3119 . PMC   5390774 . PMID   28413721.
  16. ↑ Norton, Luke Allan (2013-02-01). Relative growth and morphological variation in the skull of Aelurognathus (therapsida: gorgonopsia) (Thesis).
  17. ↑ Gebauer, Eva V. I. (2014), "Re-assessment of the Taxonomic Position of the Specimen GPIT/RE/7113 (Sauroctonus parringtoni comb. Nov., Gorgonopsia)", in Kammerer, Christian F.; Angielczyk, Kenneth D.; Fröbisch, Jörg (eds.), Early Evolutionary History of the Synapsida, Vertebrate Paleobiology and Paleoanthropology, Springer Netherlands, pp. 185–207, doi:10.1007/978-94-007-6841-3_12, ISBN   9789400768413
  18. ↑ Kammerer, Christian F. (2014), "A Redescription of Eriphostoma microdon Broom, 1911 (Therapsida, Gorgonopsia) from the Tapinocephalus Assemblage Zone of South Africa and a Review of Middle Permian Gorgonopsians", in Kammerer, Christian F.; Angielczyk, Kenneth D.; Fröbisch, Jörg (eds.), Early Evolutionary History of the Synapsida, Vertebrate Paleobiology and Paleoanthropology, Springer Netherlands, pp. 171–184, doi:10.1007/978-94-007-6841-3_11, ISBN   9789400768413
  19. ↑ Kammerer, Christian F. (2015). "Cranial osteology of Arctognathus curvimola, a short-snouted gorgonopsian from the Late Permian of South Africa". Papers in Palaeontology. 1 (1): 41–58. doi: 10.1002/spp2.1002 . ISSN   2056-2802.
  20. ↑ Kammerer, Christian F.; Smith, Roger M. H.; Day, Michael O.; Rubidge, Bruce S. (2015). "New information on the morphology and stratigraphic range of the mid-Permian gorgonopsian Eriphostoma microdon Broom, 1911". Papers in Palaeontology. 1 (2): 201–221. doi:10.1002/spp2.1012. ISSN   2056-2802. S2CID   128762256.
  21. ↑ Fröbisch, Jörg; Fernandez, Vincent; Kardjilov, Nikolay; Kammerer, Christian F.; Bendel, Eva-Maria (2018-11-28). "Cranial anatomy of the gorgonopsian Cynariops robustus based on CT-reconstruction". PLOS ONE. 13 (11): e0207367. Bibcode:2018PLoSO..1307367B. doi: 10.1371/journal.pone.0207367 . ISSN   1932-6203. PMC   6261584 . PMID   30485338.
  22. ↑ Kammerer, C. F.; Rubidge, B. S. (2022). "The earliest gorgonopsians from the Karoo Basin of South Africa". Journal of African Earth Sciences. 194: 104631. Bibcode:2022JAfES.19404631K. doi:10.1016/j.jafrearsci.2022.104631. S2CID   249977414.
  23. ↑ 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.
  24. ↑ Parrington, F. R. "A new genus of gorgonopsid from East Africa." Annals of the South African Museum 64 (1974): 47-52.
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