Eriphostoma

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Eriphostoma
Temporal range: Middle Permian, Capitanian
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Eriphostoma skull.jpg
Skull
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Clade: Gorgonopsia
Genus: Eriphostoma
Broom, 1911
Type species
Eriphostoma microdon
Broom, 1911
Synonyms
  • Eoarctops vanderbyliHaughton, 1929
  • Galesuchus gracilisHaughton, 1915
  • Scylacognathus parvusHaughton, 1913

Eriphostoma is an extinct genus of gorgonopsian therapsids known from the Middle Permian (middle Capitanian stage) 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.

Contents

History

Eriphostoma was named in 1911 by Robert Broom, based on a poorly preserved specimen collected by the Reverend J. H. Whaits in the town of Fraserburg Road (now Leeu-Gamka), South Africa. [1] The holotype was accessioned in the American Museum of Natural History with the specimen number AMNH FARB 5524. It was the first named gorgonopsian from the Tapinocephalus Assemblage Zone of the Beaufort Group. [2] Despite its status as one of the oldest known gorgonopsians, its poor preservation meant that the specimen was largely ignored for the rest of the 20th century, and typically regarded as a nomen dubium . A 1989 comprehensive revision of gorgonopsians only briefly mentioned it as an indeterminate theriodont. [3]

However, in 2014, CT scanning of the holotype allowed its redescription as a valid species of gorgonopsian. [2] Further study, and the discovery of new specimens, allowed most gorgonopsians from the Tapinocephalus AZ to be synonymized. The species Eriphostoma microdon, Scylacognathus parvus, Galesuchus gracilis, and Eoarctops vanderbyli were synonymized, and Eriphostoma microdon became the valid name due to the Principle of Priority. [4] A fifth species of Tapinocephalus AZ gorgonopsian, Broomisaurus planiceps, is probably also synonymous, but it is currently a nomen dubium due to its poor state of preparation.

Description

Restoration of the head Eoarctops.jpg
Restoration of the head

Gorgonopsians were a morphologically conservative group, and like all gorgonopsians, Eriphostoma would have been a quadrupedal predator. It was among the smaller members of the group, [5] with a skull less than 15 centimetres (5.9 in) long. It had a relatively short, deep snout and large orbits compared to other gorgonopsians. Like all gorgonopsians, it had five incisors and a canine tooth on each side of the upper jaw, but it had only three small postcanine teeth in its maxilla. [4] The palate of Eriphostoma has delta-shaped palatine bosses covered in numerous teeth, like Gorgonops and many basal therapsids, but not more derived gorgonopsians which tend to have ridge-like palatine bosses with few teeth. [2]

Classification

Eriphostoma is one of the most basal member of an endemic African radiation of gorgonopsians. [6]

Gorgonopsia

Palaeoenvironment

Restoration Eoarctops BW.jpg
Restoration

All known specimens of Eriphostoma are from the Beaufort Group of South Africa. The holotype is from the Abrahamskraal Formation, but some of the referred specimens are from the overlying Teekloof Formation. Biostratigraphically, it ranges from the upper Tapinocephalus Assemblage Zone to the upper Pristerognathus Assemblage Zone, and is the oldest known gorgonopsian. [4]

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, possibly even up to the Early Triassic, 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>Gorgonops</i> Extinct genus of therapsids

Gorgonops is an extinct genus of gorgonopsian therapsid, of which it is the type genus. Gorgonops lived during the Late Permian (Wuchiapingian), about 260–254 million years ago in what is now South Africa.

<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>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>Anteosaurus</i> Extinct genus of anteosaurid synapsid from the Permian

Anteosaurus is an extinct genus of large carnivorous dinocephalian synapsid. It lived at the end of the Guadalupian during the Capitanian stage, about 265 to 260 million years ago in what is now South Africa. It is mainly known by cranial remains and few postcranial bones. Measuring 5–6 m (16–20 ft) long and weighing about 600 kg (1,300 lb), Anteosaurus was the largest known carnivorous non-mammalian synapsid and the largest terrestrial predator of the Permian period. Occupying the top of the food chain in the Middle Permian, its skull, jaws and teeth show adaptations to capture large prey like the giants titanosuchids and tapinocephalids dinocephalians and large pareiasaurs.

<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>Pristerognathus</i> Assemblage Zone

The Pristerognathus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the upper Abrahamskraal Formation and lowermost 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 not more than 300 metres (980 ft), occur just east of Sutherland through to Beaufort West in the south and Victoria West in the north. Exposures are also found west of Colesberg and south of Graaff-Reinet. The Pristerognathus Assemblage Zone is the third biozone of the Beaufort Group.

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

Rubidgea is a genus of gorgonopsid from the upper Permian of South Africa and Tanzania, containing the species Rubidgea atrox. 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, Sydney 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.

<i>Styracocephalus</i>

Styracocephalus platyrhynchus is an extinct genus of dinocephalian therapsid that existed during the mid-Permian throughout South Africa, but mainly in the Karoo Basin. It is often referred to by its single known species Styracocephalus platyrhynchus. The Dinocephalia clade consisted of the largest land vertebrates and herbivores during the early to mid-Permian. This period is often also referred to as the Guadalupian epoch, approximately 270 to 260 million years ago.

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

Aelurosaurus is a small, carnivorous, extinct genus of gorgonopsian therapsids from the Late Permian of South Africa. It was discovered in the Karoo Basin of South Africa, and first named by Richard Owen in 1881. It was named so because it appeared to be an ancestor for cat-like marsupials, but not yet a mammal itself. It contains five species, A. felinus, A. whaitsi, A. polyodon, A. wilmanae, and A.? watermeyeri. A. felinus, the type species, is generally well described with established features, while the other four species are not due to their poorly preserved holotypes.

<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>Broomisaurus</i> Extinct genus of therapsids

Broomisaurus is an extinct genus of Gorgonopsia. It was first named by Joleaud in 1920, and contains the single species B. planiceps. Gebauer (2007) considered Broomisaurus to be a nomen dubium, indistinguishable as a separate taxon of gorgonopsian because it is based on only a fragmentary remains. A 2015 paper on Eriphostoma tentatively agreed with Gebauer's determination, but did not rule out the possibility that Broomisaurus might be synonymous with Eriphostoma.

<i>Scymnosaurus</i> Extinct genus of therapsids from middle Permian South Africa

Scymnosaurus is a dubious genus of therocephalian therapsids based upon various fossils of large early therocephalians. The genus was described by Robert Broom in 1903 with S. ferox, followed by S. watsoni in 1915 and a third, S. major, by Lieuwe Dirk Boonstra in 1954. Each of these species are considered nomen dubia today and based upon specimens belonging to two separate families of therocephalians. S. ferox and S. major represent specimens of Lycosuchidae incertae sedis, while S. watsoni is Scylacosauridae incertae sedis. Broom named a fourth species in 1907 from KwaZulu-Natal, S. warreni, though he later referred it to Moschorhinus as a valid species in 1932 but now is recognised as being synonymous with M. kitchingi.

Trochosuchus is a dubious genus of therocephalian therapsid from the middle Permian (Capitanian) of South Africa based on a weathered and poorly preserved undiagnostic fossil of a lycosuchid therocephalian. It includes the type and only species, T. acutus. Trochosuchus was named by palaeontologist Robert Broom in 1908 based on its supposedly unique proportions of the simulatenous 'double' functional canines thought to be characteristic of lycosuchids, with the pair in front being noticeably smaller than the second pair behind.

"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">Abrahamskraal Formation</span> Geological formation of the Beaufort Group in South Africa

The Abrahamskraal Formation is a geological formation and is found in numerous localities in the Northern Cape, Western Cape, and the Eastern Cape of South Africa. It is the lowermost formation of the Adelaide Subgroup of the Beaufort Group, a major geological group that forms part of the greater Karoo Supergroup. It represents the first fully terrestrial geological deposits of the Karoo Basin. Outcrops of the Abrahamskraal Formation are found from the small town Middelpos in its westernmost localities, then around Sutherland, the Moordenaarskaroo north of Laingsburg, Williston, Fraserburg, Leeu-Gamka, Loxton, and Victoria West in the Western Cape and Northern Cape. In the Eastern Cape outcrops are known from Rietbron, north of Klipplaat and Grahamstown, and also southwest of East London.

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

Nochnitsa is an extinct genus of gorgonopsian therapsids who lived during an uncertain stage of the Permian in what is now European Russia. Only one species is known, N. geminidens, described in 2018 from a single specimen including a complete skull and some postcranial remains, discovered in the red beds of Kotelnich, Kirov Oblast. The genus is named in reference to Nocnitsa, a nocturnal creature from Slavic mythology. This name is intended as a parallel to the Gorgons, which are named after many genera among gorgonopsians, as well as for the nocturnal behavior inferred for the animal. The only known specimen of Nochnitsa is one of the smallest gorgonopsians identified to date, with a skull measuring close to 8 cm (3.1 in) in length. The rare postcranial elements indicate that the animal's skeleton should be particularly slender.

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. 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 in the fossil record. 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 gorgonopsian from the older underlying Eodicynodon Assemblage Zone.

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

Nyaphulia is an extinct genus of dicynodont therapsid from the middle Permian of South Africa, containing only the type species N. oelofseni. The generic name is in honour of John Nyaphuli of the National Museum of Bloemfontein, who contributed extensively to South African palaeontology and discovered the holotype specimen of Nyaphulia in 1982. Nyaphulia was initially named as a second species of the basal dicynodont Eodicynodon by Professor Bruce Rubidge in 1990 as E. oelofseni, named after his mentor in palaeontology and geology Dr. Burger Oelofsen.

References

  1. Broom, R. (1911). "On some new South African Permian reptiles". Proceedings of the Zoological Society of London. 81 (4): 1073–1082. doi:10.1111/j.1096-3642.1911.tb01976.x.
  2. 1 2 3 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. pp. 171–184. doi:10.1007/978-94-007-6841-3_11. ISBN   978-94-007-6840-6.
  3. Sigogneau-Russell, Denise (1989). Wellnhofer, Peter (ed.). Theriodontia I: Phthinosuchia, Biarmosuchia, Eotitanosuchia, Gorgonopsia. Encyclopedia of Paleoherpetology. Vol. 17 B/I. Stuttgart: Gustav Fischer Verlag. ISBN   3437304879.
  4. 1 2 3 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.
  5. Frank Zachos, Robert Asher (October 22, 2018). Mammalian Evolution, Diversity and Systematics. De Gruyter. p. 159. ISBN   9783110341553 . Retrieved 2022-08-25.
  6. Kammerer, Christian F.; Rubidge, Bruce 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.