Australosyodon

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Australosyodon
Temporal range: Middle Permian, 265  Ma
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Australosyodon DB.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Suborder: Dinocephalia
Family: Anteosauridae
Genus: Australosyodon
Rubidge, 1994
Species:
A. nyaphuli
Binomial name
Australosyodon nyaphuli
Rubidge, 1994

Australosyodon is an extinct genus of dinocephalian therapsids from the middle Permian of South Africa. The first fossil was discovered in the 1980s near the village of Prince Albert Road in the Karoo region of South Africa. [1]

Contents

The genus is closely related to the genus Syodon , found in the Russian Ischejewo fauna, and is thus regarded as the earliest example of an anteosaurid Dinocephalia outside of Russia. Australosyodon fossils have been recovered from the Eodicynodon Assemblage Zone, the lowest bank of the South African Beaufort Group, indicating the presence of primitive early therapsids in the southern hemisphere. The genus was first described by Bruce S. Rubidge in 1994. [2]

Description

Australosyodon was a medium-sized dinocephalian. The skull was high and narrow, with a length of 26 cm, indicating a total body length of approximately 1.8 m (6 ft). [3] The top of the skull displayed the thickening typical of dinocephalians. Overall there are many similarities to the skull of Syodon, although some minor differences in shape and in the extent of pachyostosis are present. The fangs were laterally compressed and featured a rearward-facing central cutting edge. Shape, number and arrangement of teeth are among the characteristics that allow distinguishing Australosyodon from Syodon. [2]

Classification

Australosyodon is regarded as a very primitive anteosaurid dinocephalian and as first known representative of that group in the southern hemisphere. Like Syodon, Australosyodon lacked the features typical for the more apomorphic members of the anteosauridae, e.g. the boss on the lower mandible found in Anteosaurus or Titanophoneus . These two closely related genera have therefore been combined into a subgenus Syodontinae. [4]

Australosyodon in a cladogram after Cisneros et al. (2012): [5]

Therapsida

Biarmosuchus tener

Dinocephalia

Estemmenosuchus uralensis

Ulemosaurus svijagensis

Tapinocaninus pamelae

Anteosauridae

Archaeosyodon praeventor

Anteosaurinae

Sinophoneus yumenensis

Titanophoneus adamanteus

Titanophoneus potens

Anteosaurus magnificus

Syodontinae

Pampaphoneus biccai

Notosyodon gusevi

Syodon biarmicum

Australosyodon nyaphuli

See also

Related Research Articles

<span class="mw-page-title-main">Dinocephalia</span> Extinct clade of stem-mammals

Dinocephalians are a clade of large-bodied early therapsids that flourished in the Early and Middle Permian between 279.5 and 260 million years ago (Ma), but became extinct during the Capitanian mass extinction event. Dinocephalians included herbivorous, carnivorous, and omnivorous forms. Many species had thickened skulls with many knobs and bony projections. Dinocephalians were the first non-mammalian therapsids to be scientifically described and their fossils are known from Russia, China, Brazil, South Africa, Zimbabwe, and Tanzania.

<span class="mw-page-title-main">Biarmosuchia</span> Extinct suborder of therapsids

Biarmosuchia is an extinct clade of non-mammalian synapsids from the Permian. Biarmosuchians are the most basal group of the therapsids. They were moderately-sized, lightly built carnivores, intermediate in form between basal sphenacodont "pelycosaurs" and more advanced therapsids. Biarmosuchians were rare components of Permian ecosystems, and the majority of species belong to the clade Burnetiamorpha, which are characterized by elaborate cranial ornamentation.

<span class="mw-page-title-main">Anteosaur</span> Extinct clade of therapsids

Anteosaurs are a group of large, primitive carnivorous dinocephalian therapsids with large canines and incisors and short limbs, that are known from the Middle Permian of South Africa, Russia, China, and Brazil. Some grew very large, with skulls 50–80 centimetres (20–31 in) long, and were the largest predators of their time. They died out at the end of the Middle Permian, possibly as a result of the extinction of the herbivorous Tapinocephalia on which they may have fed.

<span class="mw-page-title-main">Anteosauridae</span> Extinct family of therapsids

Anteosauridae is an extinct family of large carnivorous dinocephalian therapsids that are known from the Middle Permian of Asia, Africa, and South America.These animals were by far the largest predators of the Permian period, with skulls reaching 80 cm in length in adult individuals, far larger than the biggest gorgonopsian.

<span class="mw-page-title-main">Estemmenosuchidae</span> Extinct family of therapsids

Estemmenosuchidae is an extinct family of large, very early herbivorous therapsids that flourished during the Guadalupian period. They are distinguished by horn-like structures, probably for display or agonistic behavior. Apart from the best known genus, Estemmenosuchus, the group is poorly known. To date, their fossils are known only from the Perm region of Russia.

<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>Eodicynodon</i> Extinct genus of dicynodonts

Eodicynodon is an extinct genus of dicynodont therapsids, a highly diverse group of herbivorous synapsids that were widespread during the middle-late Permian and early Triassic. As its name suggests, Eodicynodon is the oldest and most primitive dicynodont yet identified, ranging from the middle to late Permian and possessing a mix of ancestral Anomodont/therapsid features and derived dicynodont synapomorphies.

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

Tapinocaninus is an extinct genus of therapsids in the family Tapinocephalidae, of which it is the most basal member. Only one species is known, Tapinocaninus pamelae. The species is named in honor of Rubidge's mother, Pam. Fossils have been found dating from the Middle Permian.

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

Microurania is an extinct genus of therapsids from the Middle Permian first named and described by Mikhaïl Ivakhnenko. It is known from a single partial skull found in the region of Orenburg, Russia. According to Kammerer, 2011, it likely represents the remains of a juvenile dinocephalian.

<i>Styracocephalus</i>

Styracocephalus platyrhynchus (Greek for “spiked-head”) 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>Paraburnetia</i> Extinct genus of therapsids

Paraburnetia is an extinct genus of biarmosuchian therapsids from the Late Permian of South Africa. It is known for its species P. sneeubergensis and belongs to the family Burnetiidae. Paraburnetia lived just before the Permian–Triassic mass extinction event.

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

Raranimus is an extinct genus of therapsids of the Middle Permian. It was described in 2009 from a partial skull found in 1998 from the Dashankou locality of the Qingtoushan Formation, outcropping in the Qilian Mountains of Gansu, China. The genus is the most basal known member of the clade Therapsida, to which the later Mammalia belong.

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

Criocephalosaurus is an extinct genus of tapinocephalian therapsids that lived in Southern Africa during the Guadalupian epoch of the Permian. They are the latest surviving dinocephalians, extending past the Abrahamskraal Formation into the lowermost Poortjie Member of the Teekloof Formation in South Africa. They are also regarded as the most derived of the dinocephalians, alongside Tapinocephalus, and the most abundant in the fossil record.

<span class="mw-page-title-main">Venyukovioidea</span> Extinct infraorder of therapsids

Venyukovioidea is an infraorder of anomodont therapsids related to dicynodonts from the Permian of Russia. They have also been known as 'Venjukovioidea', as well as by the similar names 'Venyukoviamorpha' or 'Venjukoviamorpha' in literature. This in part owes to a misspelling by Russian palaeontologist Ivan Efremov in 1940 when he mistakenly spelt Venyukovia, the namesake of the group, with a 'j' instead of a 'y', which permeated through subsequent therapsid literature before the mistake was caught and corrected. The order Ulemicia has also been coined for a similar taxonomic concept in Russian scientific literature, which notably excludes Suminia and Parasuminia.

<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>Pampaphoneus</i> Extinct genus of therapsids

Pampaphoneus is an extinct genus of carnivorous dinocephalian therapsid belonging to the family Anteosauridae. It lived 268 to 265 million years ago during the Wordian age of the Guadalupian period in what is now Brazil. Pampaphoneus is known by an almost complete skull with the lower jaw still articulated, discovered on the lands of the Boqueirão Farm, near the city of São Gabriel, in the state of Rio Grande do Sul. A second specimen from the same locality was reported in 2019 and 2020 but has not yet been described. It is composed of a skull associated with postcranial remains. It is the first South American species of dinocephalian to have been described. The group was previously known in South America only by a few isolated teeth and a jaw fragment reported in 2000 in the same region of Brazil. Phylogenetic analysis conducted by Cisneros and colleagues reveals that Pampaphoneus is closely related to anteosaurs from European Russia, indicating a closer faunal relationship between South America and Eastern Europe than previously thought, thus promoting a Pangea B continental reconstruction.

<span class="mw-page-title-main">Syodontinae</span> Extinct subfamily of mammal ancestors

Syodontinae is a group of dinocephalian therapsids. It is one of two subfamilies in the family Anteosauridae, the other being Anteosaurinae. They are known from the Middle Permian Period of what is now Russia and South Africa. One of the best known syodontines is Syodon from Russia. The South African form Australosyodon, is one of the earliest known Gondwanan anteosaurs.

<span class="mw-page-title-main">Anteosaurinae</span> Extinct subfamily of therapsids

Anteosaurinae is an extinct subfamily of dinocephalian therapsids. It is one of two subfamilies in the family Anteosauridae, the other being Syodontinae.

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

Sinophoneus is an extinct genus of carnivorous dinocephalian therapsid belonging to the family Anteosauridae. It lived 272 to 270 million years ago at the beginning of the Middle Permian in what is now the Gansu Province in northern China. It is known by a skull of an adult individual, as well as by many skulls of juvenile specimens. The latter were first considered as belonging to a different animal, named Stenocybus, before being reinterpreted as immature Sinophoneus. Sinophoneus shows a combination of characters present in other anteosaurs. Its bulbous profile snout and external nostrils located in front of the canine are reminiscent of the basal anteosaur Archaeosyodon, while its massive transverse pterygoids processes with enlarged distal ends are more similar to the more derived anteosaurs Anteosaurus and Titanophoneus. First phylogenetic analyzes identified Sinophoneus as the most basal Anteosaurinae. A more recent analysis positioned it outside the Anteosaurinae and Syodontinae subclades, and recovers it as the most basal Anteosauridae.

References

  1. "Palaeontologists find South America's oldest predator".
  2. 1 2 Bruce S. Rubidge (1994). "Australosyodon. The first primitive Anteosaurid Dinocephalian from the Upper Permian of Gondwana" (PDF). Palaeontology. 37 (3): 579–594. Archived from the original (PDF) on 2011-07-16.
  3. "Australosyodon".
  4. Christian Kammerer (2011). "Systematics of the Anteosauria (Therapsida: Dinocephalia)". Journal of Systematic Palaeontology. 9 (2): 261–304. doi:10.1080/14772019.2010.492645.
  5. Cisneros, J.C.; Abdala, F.; Atayman-Güven, S.; Rubidge, B.S.; Şengör, A.M.C.; Schultz, C.L. (2012). "Carnivorous dinocephalian from the Middle Permian of Brazil and tetrapod dispersal in Pangaea". Proceedings of the National Academy of Sciences of the United States of America. 109 (5): 1584–1588. doi: 10.1073/pnas.1115975109 . PMC   3277192 . PMID   22307615.