Spinostropheus

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Spinostropheus
Temporal range: Middle Jurassic, 167–164 Ma
Life restoration of S. gautieri
Scientific classification Edit this classification
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)

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.

History of discovery[edit]

In 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 e.a. referred a third skeleton, specimen MNN TIG6 consisting of a series of cervical and dorsal vertebrae together with some ribs.[2] However, this specimen differs from Spinostropheus and likely belong to a different Noasaurid taxon.[4]

Description[edit]

Spinostropheus 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).[5] In 2012 Thomas R. Holtz Jr gave a length of 6.2 meters (20.3 feet).[6]

Classification[edit]

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.[7] 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.[8] According to Carrano et al. (2012), this taxon is a basal Tetanuran.[9] 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.[10]

The authors of the description of Spectrovenator recover it as sister to Averostra and MNN TIG6 as the basalmost Noasaurid in a clade with Camarillasaurus:[11]

Herrerasaurus

Neotheropoda

See also[edit]

References[edit]

  1. ^ 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
  2. ^ 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.
  3. ^ 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.
  4. ^ academic.oup.com https://academic.oup.com/zoolinnean/article/178/3/546/2667468?login=false. Retrieved 2024-03-03. {{cite web}}: Missing or empty |title= (help)
  5. ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 78
  6. ^ Holtz Jr., Thomas R. (2012). "Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages" (PDF).
  7. ^ 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.
  8. ^ 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.
  9. ^ 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.
  10. ^ 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.
  11. ^ 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.