Spinostropheus is a genus of carnivorous neotheropod theropod dinosaur that lived in the Middle Jurassic period and has been found in the Tiouraren Formation, Niger. The type and only species is S. gautieri.
| Spinostropheus Temporal range: Middle Jurassic,
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| Speculative life restoration of Spinostropheus as a generalized theropod | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Neotheropoda |
| Genus: | †Spinostropheus Sereno et al. 2004 |
| Type species | |
| †Spinostropheus gautieri Lapparent, 1960 (originally Elaphrosaurus gautieri)
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History of discovery
editIn 1959, Albert-Félix de Lapparent excavated fossils near Oued Timmersöi, west of In Tedreft in the Agadez desert. Among the finds were the remains of a theropod. In 1960, de Lapparent, based on these, named a second species of the genus Elaphrosaurus, E. gautieri. The specific name honours François Gautier, the discoverer of the type locality.[1]
In 2004, Paul Sereno, John Wilson and John Conrad named a separate genus: Spinostropheus. The generic name is derived from Latin spina, "spine", and Greek στροφεύς, stropheus, "vertebra", and refers to the epipophyseal processes of the cervical vertebrae, which are prominent and dorso-ventrally flattened.[2]
The holotype, MNHN 1961-28, was found in a layer of the Tiouraren Formation dating from the Bathonian-Oxfordian.[3] De Lapparent had presumed that the strata dated from the Early Cretaceous. It consists of a cervical vertebra, seven pieces of the dorsals, three pieces of the sacrum, five tail vertebrae, a humerus, the lower end of a pubic bone, the lower end of a thighbone, a piece of a shinbone, a piece of a fibula, a metatarsal, four additional pieces of the metatarsus and a phalanx of a toe. The paratypes were an ulna, a metatarsal and a second partial skeleton consisting of vertebrae and limb elements. In 2004, Sereno et al. referred a third skeleton, specimen MNN TIG6 consisting of a series of cervical and dorsal vertebrae with some ribs.[2] However, this specimen differs from Spinostropheus and likely belongs to a different noasaurid taxon.[4] Other material referred to it includes cervical, dorsal, and caudal vertebra, partial left humerus, ulna, distal pubis, distal femur, incomplete tibia, fibulae, metatarsals, pedal phalangeal fragments, and manual unguals.[5]
Description
editSpinostropheus was a relatively small theropod. In 2010, Gregory S. Paul estimated its length at 4 metres (13 feet), and its weight at 200 kg (441 lbs).[6] In 2012 Thomas R. Holtz Jr gave a length of 6.2 meters (20.3 feet).[7]
Classification
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In 2002, a cladistic analysis by Sereno et al found Spinostropheus to be the sister taxon of the Abelisauria. In this study only the data from specimen MNN TIG6 were considered.[8] Subsequent studies have recovered it as a basal ceratosaur based on the specimen MNN TIG6, outside of Neoceratosauria, more closely in the evolutionary tree to Elaphrosaurus.[9] According to Carrano et al. (2012), this taxon is a basal Tetanuran.[10] Spinostro Rauhut and Carrano (2016) believe that the holotype and paratype specimens of Spinostropheus lack ceratosaurian features, unlike the specimen MNN TIG6 which they consider ceratosaurian, and suggest that Spinostropheus might be a basal tetanuran.[11]
In their 2020 description of the abelisaurid Spectrovenator, Zaher et al. recovered the Spinostropheus holotype as the sister taxon to the Averostra. The referred specimen, MNN TIG6, was found in a clade with Camarillasaurus as the basalmost noasaurids:[12]
| Neotheropoda |
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See also
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References
edit- ^ A-F. de Lapparent, 1960, "Les Dinosauriens du "Continental intercalaire" du Saharal central", Mémoires de la Société géologique de France, nouvelle série 39(88A): 1-57
- ^ a b Sereno, P. C.; Wilson, J. A.; Conrad, J. L. (2004). "New dinosaurs link southern landmasses in the Mid-Cretaceous". Proceedings of the Royal Society B: Biological Sciences. 271 (1546): 1325–1330. doi:10.1098/rspb.2004.2692. PMC 1691741. PMID 15306329.
- ^ Rauhut, O.W.M.; Lopez-Arbarello, A. (2009). "Considerations on the age of the Tiouaren Formation (Iullemmeden Basin, Niger, Africa): Implications for Gondwanan Mesozoic terrestrial vertebrate faunas". Palaeogeography, Palaeoclimatology, Palaeoecology. 271 (3–4): 259–267. Bibcode:2009PPP...271..259R. doi:10.1016/j.palaeo.2008.10.019.
- ^ "The theropod dinosaur Elaphrosaurus bambergi Janensch, 1920, from the Late Jurassic of Tendaguru, Tanzania [X24670] matrix". MorphoBank datasets. 2020-05-06. Retrieved 2024-07-04.
- ^ Souza-Júnior, André Luis de; Candeiro, Carlos Roberto dos Anjos; Vidal, Luciano da Silva; Brusatte, Stephen Louis; Mortimer, Mickey (2023-07-05). "Abelisauroidea (Theropoda, Dinosauria) from Africa: a review of the fossil record". Papéis Avulsos de Zoologia. 63: e202363019. doi:10.11606/1807-0205/2023.63.019. ISSN 1807-0205.
- ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 78
- ^ Holtz Jr., Thomas R. (2012). "Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages" (PDF).
- ^ Sereno, P.C.; Conrad, J.L.; Wilson, J.A. (2002). "Abelisaurid theropods from Africa: Phylogenetic and biogeographic implications". Journal of Vertebrate Paleontology. 22 (3): 106A.
- ^ Carrano, M.; Sampson, S. (2008). "Phylogeny of Ceratosauria (Dinosauria: Theropoda)". Journal of Systematic Palaeontology. 6 (2): 183–236. Bibcode:2008JSPal...6..183C. doi:10.1017/s1477201907002246. S2CID 30068953.
- ^ Carrano, Matthew T.; Benson, Roger B. J.; Sampson, Scott D. (June 2012). "The phylogeny of Tetanurae (Dinosauria: Theropoda)". Journal of Systematic Palaeontology. 10 (2): 211–300. Bibcode:2012JSPal..10..211C. doi:10.1080/14772019.2011.630927. ISSN 1477-2019. S2CID 85354215.
- ^ Rauhut, Oliver W. M.; Carrano, Matthew T. (November 2016). "The theropod dinosaur Elaphrosaurus bambergi Janensch, 1920, from the Late Jurassic of Tendaguru, Tanzania". Zoological Journal of the Linnean Society. 178 (3): 546–610. doi:10.1111/zoj.12425.
- ^ Zaher, Hussam; Pol, Diego; Navarro, Bruno A.; Delcourt, Rafael; Carvalho, Alberto B. (2020-10-12). "An Early Cretaceous theropod dinosaur from Brazil sheds light on the cranial evolution of the Abelisauridae". Comptes Rendus Palevol. 19 (6): 101–115. doi:10.5852/cr-palevol2020v19a6. hdl:11336/153682. ISSN 1777-571X.