Polysphenodon is an extinct genus of sphenodontian reptile with a single species Polysphenodon mulleri from the Late Triassic Keuper Group of Germany.[1]
| Polysphenodon Temporal range: Late Triassic,
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| Genus: | †Polysphenodon Jaeckel, 1911
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| †Polysphenodon mulleri Jaeckel, 1911
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History of discovery edit
The genus and only known species Polysphenodon mulleri was described by Otto Jaekel in 1911.[2] Polysphenodon mulleri is known from a single partial skeleton recovered from a borehole sample at 775 metres (2,543 ft) depth, which includes parts of the skull, limbs and tail vertebrae.[2] This specimen has been lost since the 1930s, but is known from several casts.[1]
Description edit
The skull was around 2.5 centimetres (0.98 in) long in life. The snout is relatively short, even when accounting for post-mortem distortion. The limbs of Polysphenodon, particularly the tibia, are long relative to the size of the skull and are similar in proportions to some species of Homoeosaurus. This resemblance is considered to be indicative of similar locomotory requirements rather than close evolutionary relationships.[1]
Taxonomy edit
Recent studies have placed Polysphenodon as a member of Eusphenodontia.[3] Some authors have placed Polysphenodon as part of the family Clevosauridae alongside Clevosaurus and Brachyrhinodon[4], though other studies have recovered Polysphenodon as unrelated to these taxa.[3]
Cladogram following Sues and Schoch, 2023:[5]
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References edit
- ^ a b c N. C. Fraser and M. J. Benton. (1989) The Triassic reptiles Brachyrhinodon and Polysphenodon and the relationships of the sphenodontids. Zoological Journal of the Linnean Society 96:413-445
- ^ a b Jaekel, O (1911) Die Wierbeltiere. Eine Übersicht über diefossilen und lebenden Formen. Borntraeger, Berlin, 252p
- ^ a b Romo de Vivar, Paulo R.; Martinelli, Agustín G.; Schmaltz Hsiou, Annie; Soares, Marina Bento (2020-07-02). "A New Rhynchocephalian from the Late Triassic of Southern Brazil Enhances Eusphenodontian Diversity". Journal of Systematic Palaeontology. 18 (13): 1103–1126. Bibcode:2020JSPal..18.1103R. doi:10.1080/14772019.2020.1732488. ISSN 1477-2019.
- ^ Hsiou, Annie Schmaltz; De França, Marco Aurélio Gallo; Ferigolo, Jorge (2015-09-10). Beatty, Brian Lee (ed.). "New Data on the Clevosaurus (Sphenodontia: Clevosauridae) from the Upper Triassic of Southern Brazil". PLOS ONE. 10 (9): e0137523. Bibcode:2015PLoSO..1037523H. doi:10.1371/journal.pone.0137523. ISSN 1932-6203. PMC 4565693. PMID 26355294.
- ^ Sues, Hans-Dieter; Schoch, Rainer R. (2023-11-07). "The oldest known rhynchocephalian reptile from the Middle Triassic (Ladinian) of Germany and its phylogenetic position among Lepidosauromorpha". The Anatomical Record. 307 (4): 776–790. doi:10.1002/ar.25339. ISSN 1932-8486. PMID 37937325. S2CID 265050255.
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