Spinostropheus
Spinostropheus is a genus of carnivorous ceratosaurian 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, | |
|---|---|
| Life restoration of S. gautieri | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | †Ceratosauria |
| Genus: | †Spinostropheus Sereno et al. 2004 |
| Type species | |
| †Spinostropheus gautieri Lapparent, 1960 (originally Elaphrosaurus gautieri) | |
History of discovery
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]
Description
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).[4] In 2012 Thomas R. Holtz Jr gave a length of 6.2 meters (20.3 feet).[5]
Phylogeny
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.[6] Subsequent studies have confirmed the original interpretation as a basal ceratosaur, outside of Neoceratosauria, more closely in the evolutionary tree to Elaphrosaurus.[7]
In 2018, Rafael Delcourt placed Spinostropheus in Noasauridae outside of Elaphrosaurinae and Noasaurinae.[8]
| Ceratosauroidea |
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See also
References
- ^ 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: 259–267. doi:10.1016/j.palaeo.2008.10.019.
- ^ 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: 183–236. doi:10.1017/s1477201907002246.
- ^ Delcourt, Rafael (2018-06-27). "Ceratosaur palaeobiology: new insights on evolution and ecology of the southern rulers". Scientific Reports. 8 (1): 9730. doi:10.1038/s41598-018-28154-x. ISSN 2045-2322. PMC 6021374. PMID 29950661.