Biology:Gorynychus
Gorynychus is a genus of basal therocephalian from the Middle to Late Permian from Kotelnich, Russia. It was named after the three-headed dragon Zmey Gorynych (Змей Горыныч) from Russian mythology. The genus contains two species, G. masyutinae and G. sundyrensis.[1][2][3] G. sundyrensis, along with Julognathus, were the only known large carnivores present in the Sundry Assemblage, replacing the anteosaurs, which went at the end of the Isheevo Assemblage Zone. With a skull length of 35–40 cm (14–16 in), it was one of the largest therocephalians.
The genus would survive the Captanian mass extinction event, with G. masyuntinae, the type species, being found in the early Late Permian rocks of the Kotelnich Tetrapod Assemblage. Despite being notably smaller than G. sundyrensis, it was the top predator of the assemblage, with contemporary gorgonopsians being much smaller.
Classification
Kammer and Masyutin (2018) recovered Gorynychus as a basal therocephalian just outside of Eutherocephalia.[1] On the other hand, Suchkova and Golubev (2019) recovered Gorynychus as a lycosuchid, following the discovery of G. sundyrensis.[3] Liu and Abdala, in their 2019 study, recovered Gorynychus as a sister taxon to Lycosuchus.[4] However, in a later study, they recovered it intermediately between Lycosuchus and Scylacosauria.[5]
Cladogram recovered by Liu & Abdala (2019):
| Theriodontia |
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Cladogram recovered by Liu & Abdala (2023):
| Theriodontia |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Description
G. masyutinae, only known from its holotype, was wolf-sized,[6] with a skull length of 20 cm (7.9 in). Like many theriodonts, it had strongly developed and prominent canine teeth. The postcanine of Gorynychus was unique among therocephalians, being labiolingually compressed and were "leaf" or "spade" shaped, with proportionally long serrations on both mesial and distal edges.[1] G. sundyrensis was estimated to have a skull length of 35–40 cm (14–16 in), making it one of the largest known therocephalians. It had four postcanine teeth compared to G. masyutinae, which had three. The premaxilla was low and relatively short and contained four incisors. The teeth of G. sundyrensis were noted to have been serrated.[3]
Paleoecology
Sundyr Assemblage
Within the Sundyr Assemblage fauna, G. sundyrensis coexisted with the more common Julognathus, with both therocephalians coexisting by niche partitioning, with Gorynychus occupying a scavenger niche based lifetime wears of the tooth crowns.[3] Large herbivores are poorly known, only represented by dinocephalians possibly similar to Ulemosaurus,[7] while small herbivores were represented by the anomodont Parasuminia.[8] 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 gubini.[9][7][3][10]
The Sundry Assemblage was the terminal stage of the Dinocephalian tetrapod fauna before the Capitanian mass extinction,[3][7][8] representing a crisis stage in the development of the tetrapod community in Eastern Europe and was transition from the Dinocephalian fauna to the Theriodontian fauna of the Late Permian.[11] Compared to the older Isheevo Assemblage Zone, the aquatic fauna was more similar to the Theriodontian faunas, with the chroniosuchids, karpinskiosaurids, and kotlassids appearing and becoming abundant. On the other hand, the last archegosauroids went extinct.[11] Within the terrestrial fauna, anteosaurs went extinct and were replaced by large therocephalians.[7][3][8]
Kotelnich Tetrapod Assemblage
G. masyuntinae was recovered in the Kotelnich Tetrapod Assemblage. The depositional environment of the assemblage was thought to have been a lacustrine or floodplain system.[1] Contemporary fauna include the pareiasaur Deltavjatia,[12] the anomodont Suminia,[13] the gorgonopsian Nochnitsa, and other therocephalians including Chlynovia serridentatus, Viatkosuchus sumini, and Karenites ornamentatus.[1] G. masyuntinae was the largest predator in the Kotelnich tetrapod assemblage. The contemporary gorgonopsians were smaller with skull lengths less than 10 cm (3.9 in).[1]
The date of the tetrapod assemblage was marked with uncertainty, with some studies suggesting it dated to the Middle Permian.[14][1] However, recent studies suggest the tetrapod assemblage was instead dated to the early Late Permian.[1][11][9][8] Anomodont comparisons suggest the Kotelnich assemblage may have been equivalent to the South African Tropidostoma Assemblage Zone.[15] While some experts have suggested equivalency between Kotelnich assemblage and Pristerognathus Assemblage Zone,[14] the described fauna of therocephalians between both assemblages were vastly different, with Kotelnich assemblage consisting mostly of eutherocephalians while lycosuchids and scylacosaurids were more rare. Despite being equivalent to Tropidostoma AZ, the most abundant tetrapod in the fauna was the pareiasaur Deltavjatia, in contrast, dicynodont therapsids were the most abundant tetrapods in South African faunas.[1]
The discovery of such a large therocephalian as the apex predator of its environment coupled with the discovery of a smaller gorgonopsian, the smaller and nocturnal Nochnitsa, in the same formation indicates that a faunal turnover was occurring at the time, with gorgonopsians taking over the therocephalians' role as the dominant predators in their environment.[2]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Kammerer, CF; Masyutin, V. (2018). "A new therocephalian (Gorynychus masyutinae gen. et sp. nov.) from the Permian Kotelnich locality, Kirov Region, Russia". PeerJ 6. doi:10.7717/peerj.4933. PMID 29900076.
- ↑ 2.0 2.1 North Carolina Museum of Natural Sciences (June 8, 2018). "'Monstrous' new Russian saber-tooth fossils clarify early evolution of mammal lineage". ScienceDaily. https://www.sciencedaily.com/releases/2018/06/180608085622.htm.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 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/S0031031X19040123. https://www.researchgate.net/publication/334807205_A_New_Permian_Therocephalian_Therocephalia_Theromorpha_from_the_Sundyr_Assemblage_of_Eastern_Europe.
- ↑ Liu, J.; Abdala, F. (2019). "The tetrapod fauna of the upper Permian Naobaogou Formation of China: 3. Jiufengia jiai gen. et sp. nov., a large akidnognathid therocephalian". PeerJ 7. doi:10.7717/peerj.6463. ISSN 2167-8359. PMID 30809450.
- ↑ Liu, J.; Abdala, F. (2023). "Late Permian terrestrial faunal connections invigorated: the first whaitsioid therocephalian from China". Palaeontologia Africana 56: 16–35.
- ↑ Brocklehurst, Neil (2019). "Morphological evolution in therocephalians breaks the hypercarnivore ratchet". Proc Biol Sci 286 (1900). doi:10.1098/rspb.2019.0590. PMID 30966993. PMC 6501669. https://pmc.ncbi.nlm.nih.gov/articles/PMC6501669/.
- ↑ 7.0 7.1 7.2 7.3 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. https://www.researchgate.net/publication/333895634_A_New_Primitive_Therocephalian_Theromorpha_from_the_Middle_Permian_of_Eastern_Europe.
- ↑ 8.0 8.1 8.2 8.3 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.
- ↑ 9.0 9.1 Golubev, Valeriy 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. https://www.researchgate.net/publication/328969452_Amphibians_of_the_Permian_Sundyr_Tetrapod_Assemblage_of_Eastern_Europe.
- ↑ Uliakhin, A. V.; Golubev, V. K. (2024). "Ancient Species of the Genus Dvinosaurus (Temnospondyli, Dvinosauria) from the Permian Sundyr Tetrapod Assemblage of Eastern Europe". Paleontological Journal 58 (2): 204–225. doi:10.1134/S0031030123600336. https://www.researchgate.net/publication/379878533_Ancient_species_of_the_genus_Dvinosaurus_Temnospondyli_Dvinosauria_from_the_Permian_Sundyr_Tetrapod_Assemblage_of_Eastern_Europe.
- ↑ 11.0 11.1 11.2 Golubev, Valeriy K. (2015). "Dinocephalian stage in the history of the Permian tetrapod fauna of Eastern Europe". Paleontological Journal 49 (12): 1346-1352. doi:10.1134/S0031030115120059. https://www.researchgate.net/publication/288701331_Dinocephalian_stage_in_the_history_of_the_Permian_tetrapod_fauna_of_Eastern_Europe.
- ↑ Kiseleva, Daria; Shilovsky, Oleg; Shagalov, Evgeny; Ryanskaya, Anastasia; Chervyakovskaya, Maria; Pankrushina, Elizaveta; Cherednichenkoa, Nadezhda (15 July 2019). "Composition and structural features of two Permian parareptile (Deltavjatia vjatkensis, Kotelnich Site, Russia) bone fragments and their alteration during fossilisation". Palaeogeography, Palaeoclimatology, Palaeoecology 526: 28–42. doi:10.1016/j.palaeo.2019.04.015. https://www.sciencedirect.com/science/article/pii/S0031018218304589. Retrieved 4 June 2022.
- ↑ Fröbisch, J. and Reisz, R. R. 2009. The Late Permian herbivore Suminia and the early evolution of arboreality in terrestrial vertebrate ecosystems. Proceedings of the Royal Society B, 276: 3611–3618.
- ↑ 14.0 14.1 Benton, Michael J.; Newell, Andrew J.; Khlyupin, Al'bert Yu.; Shumov, Il'ya S.; Price, Gregory D.; Kurkin, Andrey A. (2012-02-15). "Preservation of exceptional vertebrate assemblages in Middle Permian fluviolacustrine mudstones of Kotel'nich, Russia: stratigraphy, sedimentology, and taphonomy". Palaeogeography, Palaeoclimatology, Palaeoecology 319-320: 58–83. doi:10.1016/j.palaeo.2012.01.005. ISSN 0031-0182. https://www.sciencedirect.com/science/article/pii/S0031018212000193.
- ↑ Kurkin, A. A. (2011). "Permian Anomodonts: Paleobiogeography and Distribution of the Group". Paleontological Journal 45 (4): 432-444. doi:10.1134/S0031030111030075. https://link.springer.com/article/10.1134/S0031030111030075.
Template:Therocephalia Wikidata ☰ Q54969218 entry
 |  |
