Parasuminia

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Parasuminia
Temporal range: Middle Permian, Late Capitanian ~259  Ma
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Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Suborder:† Anomodontia
Genus:† Parasuminia
Kurkin, 2017
Species:
†P. ivakhnenkoi
Binomial name
†Parasuminia ivakhnenkoi
Kurkin, 2017

Parasumina is an extinct genus of anomodont known from the late Capitanian age at the end of the middle Permian period of European Russia. The type and only species is Parasuminia ivakhnenkoi. It was closely related to Suminia , another Russian anomodont, and was named for its resemblance ("similar to Suminia"). Little is known about Parasuminia as the only fossils are of fragmentary pieces of the skull and jaw, but the known remains suggest that its head and jaws were deeper and more robust than those of Suminia, and with shorter, stouter teeth. However, despite these differences they appear to have been similar animals with a similarly complex method of processing vegetation.

Contents

History of discovery

Fossils of Parasuminia are known exclusively from a locality known as Sundyr-1 near the mouth of the Sundyr River (a tributary to the Volga River) in the Mari El Republic of European Russia, and were first discovered in 2009 by an expedition from the Borissiak Paleontological Institute of the Russian Academy of Sciences, Moscow. The site itself was originally discovered by a group of schoolboys in 1997, and the site and its fossils were briefly reported on by A. Yu. Bezerin in 2005 who referred to the site as the "Yul’yaly locality". [1] The site was later renamed Sundyr-1 and interpreted to belong to a new stratigraphic member, the Ustpoldarsa Member, of the Poldarsa Formation. [2] The fossil fauna recovered from Sundyr-1 have been collated into the Sundyr Assemblage Zone, interpreted as representing an intermediate fauna between the older Middle Permian 'dinocephalian faunas' and later 'theriodontian faunas' of the Late Permian. The Sundyr Assemblage has been interpreted as belonging to the lower Upper Severodvinian stage in Russian stratigraphy, correlating to the upper Capitanian stage of the International Stratigraphic Scale dating to approximately 259 million years ago. [3] [4]

The remains of Parasuminia were initially referred to as 'aff. Suminia', and were later described as a distinct genus and species in 2017 by A. A. Kurkin. [1] [2] The holotype specimen, PIN no. 5388/196, consists of a partial pair of lower jaws with teeth. Other specimens include numerous lower jaw fragments, a single partial premaxilla and many isolated teeth. An isolated right parietal, PIN no. 5388/198, may also belong to Parasuminia. The remains of Parasuminia currently consist only of fragmented, disarticulated pieces of skull as well as isolated pairs of dentaries that remain held together by strong suturing at the jaw tips. The generic name is from the Ancient Greek "para" ("close", "similar") and the genus Suminia for its close resemblance and relationship to the latter. The specific name is in memory of the palaeontologist Mikhail F. Ivakhnenko and in recognition of his "outstanding" work on Russian palaeontology. [1]

Description

Parasuminia is only known from incomplete remains of the lower jaw and the front of the snout. Compared to Suminia, the lower jaw is deeper and more robust, and is down-turned towards its tip with a deep, rounded 'chin'. The teeth in both the upper and lower jaws are lower and wider than in Suminia, with serrated edges only found on the newest replacement teeth before being worn away. The tooth row consists of 10 to 12 teeth and is straight along its surface, with longer procumbent (forward projecting) incisors at the tip of the lower jaw to accommodate the down-turned tip. Likewise, the premaxilla from the front of the upper jaw is also taller than in Suminia and with relatively shorter teeth. The tips of the upper jaw are similarly deflected upwards, opposing the down-turned lower jaw, and the front teeth are also procumbent. Although incomplete, the total length of the skull was estimated to be roughly 7–8 centimetres (2.8–3.1 in) long, slightly larger than the 58 millimetres (2.3 in) long skull of Suminia. [1] [5]

The parietal bone from the back of the skull roof is larger and proportionately wider than it is in Suminia, and completely surrounds the circular pineal foramen (or "third eye"). The pineal foramen itself is raised slightly above the surface of the skull; however, it is less raised than the chimney-like structure in Suminia and has more gently sloping sides. In contrast with the smooth surface of the rest of the parietal, the bone around the pineal foramen has a rugose texture, imprinted with blood vessels. [1]

Classification

Parasuminia was assigned to the family Galeopidae by Kurkin, a family originally erected solely for the South African anomodont Galeops by palaeontologist Robert Broom in 1912. Galeops was formerly included in a group of small anomodonts known as the 'dromasaurs' together with Galechirus and Galepus , however, phylogenetic analyses of anomodonts have since shown that 'dromasaurs' are polyphyletic and so are not a natural group of related species. [6]

However, Kurkin assigned Parasuminia to Galeopidae based on an alternative taxonomic classification for anomodonts (as well as other synapsids) proposed by Russian palaeontologist M. F. Ivakhnenko. Under Ivakhnenko's taxonomy, the family Galeopidae consists of the traditional 'dromasaurs' as well as other anomodonts, including Suminia and Anomocephalus , and is classed within the suborder Dromasaurida, itself under the order Dicynodontia proper. Ivakhnenko proposed galeopids were grouped together for their use a palinal jaw stroke (pulling their lower jaw backwards to chew), a trait they share with dicynodonts which he considered to indicate they shared a common ancestry. [1] [7] This opposes modern orthodox phylogenetic classifications of anomodonts, which do not group these anomodonts together within a single clade. [6]

Parasuminia has yet to be included in a phylogenetic analysis of anomodonts, and so its evolutionary relationships outside of this scheme are unclear. However, Parasuminia was referred to the Venyukovioidea, a clade that includes Suminia but not any of the 'dromasaurs', by palaeontologists Kenneth Angielczyk and Christian Kammerer in 2018. [8]

Palaeobiology

Like other related anomodonts, Parasuminia would have been a herbivore. Due to the similarity of the wear marks left on the teeth of Parasuminia to those of Suminia, it is likely that they both fed in a similar fashion with extensive tooth-on-tooth occlusion. Furthermore, although the jaw joint of Parasuminia is unknown, it can be inferred from the pattern of wear that Parasuminia was capable of a palinal jaw stroke to shred vegetation. This complex method of chewing is shared with both Suminia and the dicynodonts. [1] [9]

Palaeoecology

In the Sundyr Assemblage fauna, Parasuminia coexisted with two large carnivorous therocephalians, the predatory scylacosaurid Julognathus and the suggested scavenger Gorynychus sundyrensis . Large herbivores are poorly known, and are only represented by dinocephalians possibly similar to Ulemosaurus . A number of early tetrapods are also known from this assemblage, including Leptoropha aff. talonophora, Microphon , Enosuchus sp., and the chroniosuchian Suchonica , as well as the temnospondyl amphibian Dvinosaurus sp. [3] [10] [11]

The Sundyr Assemblage fauna has been considered to be a 'crisis fauna', representing the last of the dinocephalian dominated faunas in Eurasia at the end of the Middle Permian and transitioning into the theriodontian dominated faunas of the Late Permian. [12]

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Therapsida is a major group of eupelycosaurian synapsids that includes mammals, their ancestors and relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more underneath the body, as opposed to the sprawling posture of many reptiles and salamanders.

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

Suminia is an extinct genus of basal anomodont that lived during the Tatarian age of the late Permian, spanning approximately from 268-252 Ma. Suminia is recognized the youngest non-dicynodont anomodont. Its fossil localities are primarily derived from the Kotel’nich locality of the Kirov region in Russia. However, there have been some isolated specimen found in a few different localities, all from eastern European regions of Russia.

<i>Scutosaurus</i> Extinct genus of reptiles

Scutosaurus is an extinct genus of pareiasaur parareptiles. Its genus name refers to large plates of armor scattered across its body. It was a large anapsid reptile that, unlike most reptiles, held its legs underneath its body to support its great weight. Fossils have been found in the Sokolki Assemblage Zone of the Malokinelskaya Formation in European Russia, close to the Ural Mountains, dating to the late Permian (Lopingian) between 264 and 252 million years ago.

<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.

<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. With its skull reaching 80–90 cm (31–35 in) in length and a body size estimated at more than 5 m (16 ft) in length, and 500 to 600 kg in weight, 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>Ennatosaurus</i> Extinct genus of synapsids

Ennatosaurus is an extinct genus of caseid synapsid that lived during the Middle Permian in northern European Russia. The genus is only represented by its type species, Ennatosaurus tecton, which was named in 1956 by Ivan Antonovich Efremov. The species is known from at least six skulls associated with their lower jaws, as well as from the postcranial bones of several juvenile individuals. Ennatosaurus has the typical caseid skull with a short snout tilted forward and very large external nares. However, it differs from other derived caseids by its postcranial skeleton with smaller proportions compared to the size of the skull. As with other advanced caseids, the teeth of Ennatosaurus were well suited for slicing and cutting vegetation. The presence of a highly developed hyoid apparatus indicates the presence of a massive and mobile tongue, which had to work in collaboration with the palatal teeth during swallowing. With a late Roadian - early Wordian age, Ennatosaurus is one of the last known caseids.

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

Viatkogorgon is a genus of gorgonopsian that lived during the Permian period in what is now Russia. The first fossil was found at the Kotelnich locality near the Vyatka River and was made the holotype of the new genus and species V. ivachnenkoi in 1999. The generic name refers to the river and the related genus Gorgonops—the gorgons of Greek mythology are often referenced in the names of the group. The specific name honors the paleontologist Mikhail F. Ivakhnenko. The holotype skeleton is one of the most complete gorgonopsian specimens known and includes rarely preserved elements such as gastralia and a sclerotic ring. A larger, but poorly preserved specimen has also been assigned to the species.

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

Venyukovia is an extinct genus of venyukovioid therapsid, a basal anomodont from the Middle Permian of Russia. The type and sole species, V. prima, is known only by a partial lower jaw with teeth. Venyukovia has often been incorrectly spelt as 'Venjukovia' in English literature. This stems from a spelling error made by Russian palaeontologist Ivan Efremov in 1940, who mistakenly replaced the 'y' with a 'j', which subsequently permeated through therapsid literature before the mistake was caught and corrected. Venyukovia is the namesake for the Venyukovioidea, a group of small Russian basal anomodonts also including the closely related Otsheria, Suminia, Parasuminia and Ulemica, although it itself is also one of the poorest known. Like other venyukovioids, it had large projecting incisor-like teeth at the front and lacked canines, although the remaining teeth are simple compared to some other venyukovioids, but may resemble those of Otsheria.

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

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

Ulemica is an extinct genus of venyukovioid therapsids, a type of anomodont related to dicynodonts. It lived during the Middle Permian period in what is now Russia, and is known from the Isheevo assemblage of the Amanakskaya Formation. The type species, U. invisa, was originally placed in the genus Venyukovia by Russian palaeontologist Ivan Efremov in 1940. It was later given its own genus Ulemica in 1996 by Mikhaïl Ivakhnenko, who also named a second species U. efremovi. Efremov had originally intended to name the fossils of U. invisa as 'Myctosuchus invisus', however, he later recognised their similarity to Venyukovia and chose to assign the Isheevo material to this genus and leaving 'Myctosuchus' a nomen nudum.

<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">Chainosauria</span> Extinct clade of therapsids

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<i>Purlovia</i> Extinct genus of therapsids from the Late Permian of Russia

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<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 transerse 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.

Blattoidealestes is an extinct genus of therocephalian therapsid from the Middle Permian of South Africa. The type species Blattoidealestes gracilis was named by South African paleontologist Lieuwe Dirk Boonstra from the Tapinocephalus Assemblage Zone in 1954. Dating back to the Middle Permian, Blattoidealestes is one of the oldest therocephalians. It is similar in appearance to the small therocephalian Perplexisaurus from Russia, and may be closely related.

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<span class="mw-page-title-main">Phthinosuchia</span> Extinct infraorder of mammals

Phthinosuchia is an extinct group of therapsids including two poorly known species, Phthinosuchus discors and Phthinosaurus borrisiaki, from the Middle Permian of Russia. Phthinthosuchus is known a partial crushed skull and Phthinosaurus is known from an isolated lower jaw. The two species have traditionally been grouped together based on their shared primitive characteristics, but more recent studies have proposed that they are more distantly related. Phthinosuchus is either a carnivorous gorgonopsian relative or an anteosaurian dinocephalian while Phthinosaurus is either a herbivorous rhopalodont dinocephalian or a therocephalian.

Phthinosaurus is an extinct genus of therapsids from the Middle Permian of Russia. The type species Phthinosaurus borrisiaki was named by Soviet paleontologist Ivan Yefremov in 1940 on the basis of an isolated lower jaw. Because this jaw provides few distinguishing characteristics, the evolutionary relationships of Phthinosaurus are poorly known. Yefremov named the family Phthinosuchidae in 1954 to include Phthinosaurus and the newly named Phthinosuchus, which was described on the basis of a crushed partial skull. American paleontologist Everett C. Olson placed both of these therapsids in the larger infraorder Phthinosuchia in 1961. In 1974 Leonid Tatarinov named the family Phthinosauridae to include Phthinosaurus alone, retaining Phthinosuchus within Phthinosuchidae.

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

Thliptosaurus is an extinct genus of small kingoriid dicynodont from the latest Permian period of the Karoo Basin in KwaZulu-Natal, South Africa. It contains the type and only known species T. imperforatus. Thliptosaurus is from the upper Daptocephalus Assemblage Zone, making it one of the youngest Permian dicynodonts known, living just prior to the Permian mass extinction. It also represents one of the few small bodied dicynodonts to exist at this time, when most other dicynodonts had large body sizes and many small dicynodonts had gone extinct. The unexpected discovery of Thliptosaurus in a region of the Karoo outside of the historically sampled localities suggests that it may have been part of an endemic local fauna not found in these historic sites. Such under-sampled localities may contain 'hidden diversities' of Permian faunas that are unknown from traditional samples. Thliptosaurus is also unusual for dicynodonts as it lacks a pineal foramen, suggesting that it played a much less important role in thermoregulation than it did for other dicynodonts.

Vetusodon is an extinct genus of cynodonts belonging to the clade Epicynodontia. It contains one species, Vetusodon elikhulu, which is known from four specimens found in the Late Permian Daptocephalus Assemblage Zone of South Africa. With a skull length of about 18 centimetres (7.1 in), Vetusodon is the largest known cynodont from the Permian. Through convergent evolution, it possessed several unusual features reminiscent of the contemporary therocephalian Moschorhinus, including broad, robust jaws, large incisors and canines, and small, single-cusped postcanine teeth.

References

  1. 1 2 3 4 5 6 7 Kurkin, A. A. (2017). "A new Galeopid (Anomodontia, Galeopidae) from the Permian of Eastern Europe". Paleontological Journal . 51 (3): 308–312. doi:10.1134/S0031030117030042.
  2. 1 2 Golubev, V. K.; Kurkin, A. A.; Sennikov, A. G. (2015). "On the geological age of the Sundyr faunal assemblage of Permian tetrapods from the East European Platform". Proceedings of Kazan University. Natural Sciences/Uchenye Zapiski Kazanskogo Universiteta. Seriya Estestvennye Nauki. 157 (1): 49–58.
  3. 1 2 Golubev, V. K.; Bulanov, V. V. (2018). "Amphibians of the Permian Sundyr Tetrapod Assemblage of Eastern Europe". Paleontological Journal. 52 (6): 639–652. doi:10.1134/S0031030118060059.
  4. ↑ Davydov, V. I.; Arefiev, M. P.; Golubev, V. K.; Karasev, E. V.; Naumcheva, M. A.; Schmitz, M. D.; Silantiev, V. V.; Zharinova, V. V. (2020). "Radioisotopic and biostratigraphic constraints on the classical Middle–Upper Permian succession and tetrapod fauna of the Moscow syneclise, Russia". Geology . 48 (7): 742–747. doi:10.1130/G47172.1.
  5. ↑ Rybczynski, N. (2000). "Cranial anatomy and phylogenetic position of Suminia getmanovi, a basal anomodont (Amniota: Therapsida) from the Late Permian of Eastern Europe". Zoological Journal of the Linnean Society . 130 (3): 329–373. doi: 10.1111/j.1096-3642.2000.tb01634.x .
  6. 1 2 Fröbisch, J.; Reisz, R. R. (2011). "The postcranial anatomy of Suminia getmanovi (Synapsida: Anomodontia), the earliest known arboreal tetrapod". Zoological Journal of the Linnean Society. 162 (3): 661–698. doi: 10.1111/j.1096-3642.2010.00685.x .
  7. ↑ Ivakhnenko, M. F. (2008). "Cranial morphology and evolution of Permian Dinomorpha (Eotherapsida) of eastern Europe". Paleontological Journal. 42 (9): 859–995. doi:10.1134/S0031030108090013.
  8. ↑ Angielczyk, Kenneth D.; Kammerer, Christian F. (2018). "Non-Mammalian synapsids: the deep roots of the mammalian family tree". In Zachos, Frank E.; Asher, Robert J. (eds.). Mammalian Evolution, Diversity and Systematics. Berlin: De Gruyter. p. 151. ISBN   9783110275902.
  9. ↑ Reisz, R. R. (2006). "Origin of dental occlusion in tetrapods: signal for terrestrial vertebrate evolution?". Journal of Experimental Zoology Part B: Molecular and Developmental Evolution . 306B (3): 261–277. doi:10.1002/jez.b.21115.
  10. ↑ Suchkova, J. A.; Golubev, V. K. (2019). "A new primitive therocephalian (Theromorpha) from the Middle Permian of Eastern Europe". Paleontological Journal. 53 (3): 305–314. doi:10.1134/S0031030119030158.
  11. ↑ Suchkova, J.A.; Golubev, V.K. (2019). "New Permian therocephalian (Therocephalia, Theromorpha) from the Sundyr Assemblage of Eastern Europe". Paleontological Journal (4): 87–92. doi:10.1134/S0031030119040117.
  12. ↑ Sennikov, A. G.; Golubev, V. K. (2017). "Sequence of Permian tetrapod faunas of Eastern Europe and the Permian–Triassic ecological crisis". Paleontological Journal. 51 (6): 600–611. doi:10.1134/S0031030117060077.
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