Scalenodontoides

Scalenodontoides Temporal range: Norian–Rhaetian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Therapsida
Clade:	Cynodontia
Family:	† Traversodontidae
Subfamily:	† Gomphodontosuchinae
Genus:	† Scalenodontoides
Type species
Scalenodontoides macrodontes Crompton & Ellenberger, 1957

Scalenodontoides is an extinct genus of the herbivorous cynodont family Traversodontidae. It lived during the Late Triassic in what is now South Africa. Its type species is Scalenodontoides macrodontes. ^[1] It was named in 1957 by A. W. Crompton and F. Ellenberger. ^[1] Arctotraversodon plemmyrodon was originally classified as a species of Scalenodontoides, but was given its own genus in 1992. ^[2] It is found in the Scalenodontoides Assemblage Zone of the Elliot Formation, which is named for it. ^[3] It is one of the geologically youngest traversodontids, alongside the putative traversodontid Boreogomphodon . ^[4] It is closely related to Exaeretodon and Siriusgnathus , ^[5] but is distinguished by the presence of a shelf-like expansion of its parietal called the nuchal table. ^[6] Though the largest known complete skull is only 248 millimetres (9.8 in) long, it may have been the largest non-mammalian cynodont, as an incomplete snout would have belonged to a specimen with an estimated skull length of 617 millimetres (24.3 in). ^[7]

Paleoecology

At the time this species lived, there was a single continent called Pangea. Dinosaurs already existed, but the dominant group were the pseudosuchians. Melanorosaurus , a primitive sauropodomorph, was discovered along with Scalenodontoides in the Elliot Formation in Lesotho.^{[ citation needed ]} Although an omnivore, the dinosaur was unlikely to pose a threat to Scalenodontoides due to the large size of the cynodont.

References

1. Crompton & Ellenberger 1957, p. 2.
2. Sues, Hopson & Shubin 1992.
3. Viglietti et al. 2020.
4. Miron et al. 2020, p. 6.
5. Pavanatto et al. 2018.
6. Gow & Hancox 1993, p. 162.
7. Tolchard et al. 2021, p. 14.

Bibliography

• Crompton, A W; Ellenberger, F (1957). "On a new cynodont from the Molteno beds and the origin of the Tritylodontids". Annals of the South African Museum. 44: 1–14.
• Gow, C. E.; Hancox, P. J. (1993). "First complete skull of the Late Triassic Scalenodontoides (Reptilia Cynodontia) from southern Africa". New Mexico Museum of Natural History and Science Bulletin. 3: 161–168.
• Miron, Lívia Roese; Pavanatto, Ane Elise Branco; Pretto, Flávio Augusto; Müller, Rodrigo Temp; Dias-da-Silva, Sérgio; Kerber, Leonardo (2020). "Siriusgnathus niemeyerorum (Eucynodontia: Gomphodontia): The youngest South American traversodontid?". Journal of South American Earth Sciences. 97: 102394. doi:10.1016/j.jsames.2019.102394. ISSN   0895-9811. S2CID   210628164.
• Pavanatto, Ane Elise Branco; Pretto, Flávio Augusto; Kerber, Leonardo; Müller, Rodrigo Temp; Da-Rosa, Átila Augusto Stock; Dias-da-Silva, Sérgio (2018). "A new Upper Triassic cynodont-bearing fossiliferous site from southern Brazil, with taphonomic remarks and description of a new traversodontid taxon". Journal of South American Earth Sciences. 88: 179–196. doi:10.1016/j.jsames.2018.08.016. ISSN   0895-9811. S2CID   135131520.
• Sues, Hans-Dieter; Hopson, James A.; Shubin, Neil H. (1992-06-10). "Affinities of ?Scalenodontoides plemmyridon Hopson, 1984 (Synapsida: Cynodontia) from the Upper Triassic of Nova Scotia". Journal of Vertebrate Paleontology. 12 (2): 168–171. doi:10.1080/02724634.1992.10011447. ISSN   0272-4634.
• Tolchard, Frederick; Kammerer, Christian F.; Butler, Richard J.; Hendrickx, Christophe; Benoit, Julien; Abdala, Fernando; Choiniere, Jonah N. (2021-07-26). "A new large gomphodont from the Triassic of South Africa and its implications for Gondwanan biostratigraphy". Journal of Vertebrate Paleontology. 41 (2): e1929265. doi:10.1080/02724634.2021.1929265. ISSN   0272-4634. S2CID   237517965.
• Viglietti, P.A.; McPhee, B.W.; Bordy, E.M.; Sciscio, L.; Barrett, P.M.; Benson, R.B.J.; Wills, S.; Tolchard, F.; Choiniere, J.N. (2020-06-01). "Biostratigraphy of the Scalenodontoides Assemblage Zone (Stormberg Group, Karoo Supergroup), South Africa". South African Journal of Geology. 123 (2): 239–248. doi:10.25131/sajg.123.0017. eISSN   1996-8590. ISSN   1012-0750. S2CID   225846284.