Elliotsmithia

Elliotsmithia is a small varanopid synapsid found from the late Middle Permian of South Africa. It is the sole basal synapsid "pelycosaur" known from the supercontinent Gondwana and only two specimens have been yielded to date. Its species name longiceps is derived from Latin, meaning "long head". Both known Elliotsmithia fossils were recovered from Abrahamskraal Formation rocks—within the boundaries of the Tapinocephalus Assemblage Zone—of the lower Beaufort Group.[1][2] It was named for the late Sir Grafton Elliot Smith in 1937.[3]

Elliotsmithia
Temporal range: Middle Permian
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Family: †Varanopidae
Subfamily: †Varanopinae
Genus: †Elliotsmithia
Broom, 1937
Type species
†Elliotsmithia longiceps
Broom, 1937

History of discovery

In 1917 Dr. Van Hoepen discovered the fossil holotype of Elliotsmithia. The holotype consisted of a skull, mandibles with most of the front region missing, the first four cervical vertebrae complete with atlas-axis complex, rib fragments, and dermal ossifications. Van Hoepen found the fossil in rocks associated with the Tapinocephalus Assemblage Zone near the town Prince Albert in the Western Cape. The specimen remained undescribed until renowned paleontologist and physician, Dr. Robert Broom, briefly described and named the fossil in 1937.[3] However, Broom did not go into great detail in his description. Several researchers authored papers over several decades, providing passing descriptions of the fossil.[4][5][6][7] In the 1990s, renewed research on the holotype fossil classified Elliotsmithia as a varanopseid "pelycosaur" synapsid.[8] Another specimen was found in 2001.[9]

A possible third specimen was recovered from the Pristerognathus Assemblage Zone in 2010; however, this specimen requires further research.[10]

Description

Elliotsmithia is considered to have been a small carnivore that hunted insects and small vertebrates. It had a long, slender snout complete with recurved, mediolaterally flattened serrated teeth for hooking its prey.

Stratigraphic range

Both known Elliotsmithia fossils were recovered from rock deposits of the Middle Permian Tapinocephalus Assemblage Zone, Abrahamskraal Formation of the Beaufort Group. Another possible specimen of Elliotsmithia was recovered from the lower Teekloof Formation of the latest Middle Permian-aged Pristerognathus Assemblage Zone. Elliotsmithia is an extremely important fossil species as it provides proof of the cosmopolitan range of basal varanopseid synapsids, especially within Gondwana where therapsids were the dominant fauna.

Classification

It is currently accepted that Elliotsmithia is a basal varanopid eupelycosaur synapsid and part of the informal "pelycosaur" group. Recent paleobiology analyses of its cranial bones confidently places this basal synapsid as a sister taxon to the varanopid clade composed of Varanops, Aerosaurus, and Varanodon from North America.

Little research has been endeavored on the fossils of Elliotsmithia and this species warrants further study.

See also

References
  1. Dilkes, D.W. and Reisz, R.R. (1996). "First Record of a Basal Synapsid ('Mammal-Like Reptile') in Gondwana". ResearchGate. Retrieved 2019-02-07.{{cite web}}: CS1 maint: multiple names: authors list (link)
  2. Reisz, R.R., Dilkes, D.W. and Berman, D.S. (2010-08-24). "Anatomy and relationships of Elliotsmithia longiceps Broom, a small synapsid (Eupelycosauria: Varanopseidae) from the Late Permian of South Africa". Journal of Vertebrate Paleontology. 18 (3): 602–611. doi:10.1080/02724634.1998.10011087.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. Broom, R. (1937-09-01). "A Further Contribution to our Knowledge of the Fossil Reptiles of the Karroo". Proceedings of the Zoological Society of London. B107 (3): 299–318. doi:10.1111/j.1469-7998.1937.tb00011.x. ISSN 1469-7998.
  4. Romer, A.S. and Price, L.I., 1940. Review of the Pelycosauria (No. 28). The Society.
  5. Watson, D.M.S. (1957). "On Millerosaurus and the Early History of the Sauropsid Reptiles". ResearchGate. Retrieved 2019-02-07.
  6. Olson, E.C. (1962). "Upper Permian Terrestrial Vertebrates of the Usa and Russia: 1991". ResearchGate. Retrieved 2019-02-07.
  7. Gow, C. E. (1972). "The osteology and relationships of the Millerettidae (Reptilia: Cotylosauria)". Journal of Zoology. 167 (2): 219–264. doi:10.1111/j.1469-7998.1972.tb01731.x. ISSN 1469-7998.
  8. Modesto, S. and Smith, R.M. (2001). "A new Late Permian captorhinid reptile: a first record from the South African Karoo". Journal of Vertebrate Paleontology. 21 (3): 405–409. doi:10.1671/0272-4634(2001)021[0405:anlpcr]2.0.co;2. S2CID 130581233. Retrieved 2019-02-07.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. Modesto, Sean; Sidor, Christian A.; Rubidge, Bruce S.; Welman, Johann (2001). "A second varanopseid skull from the Upper Permian of South Africa: implications for Late Permian 'pelycosaur' evolution". Lethaia. 34 (4): 249–259. doi:10.1111/j.1502-3931.2001.tb00053.x. ISSN 1502-3931.
  10. Modesto, Sean P.; Smith, Roger M. H.; Campione, Nicolás E.; Reisz, Robert R. (2011-12-01). "The last "pelycosaur": a varanopid synapsid from the Pristerognathus Assemblage Zone, Middle Permian of South Africa". Naturwissenschaften. 98 (12): 1027–1034. Bibcode:2011NW.....98.1027M. doi:10.1007/s00114-011-0856-2. ISSN 1432-1904. PMID 22009069. S2CID 27865550.
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