Spinostropheus

Spinostropheus
Temporal occurrence
Lower Cretaceous ( Hauterivium )
133.9 to 130.7 million years
Locations
Niger ( Tiourarén Formation )
Systematics
Dinosaur (dinosauria) Lizard dinosaur (Saurischia) Theropoda Ceratosauria Spinostropheus
Scientific name
Spinostropheus
Sereno et al. , 2004
species
Spinostropheus gautieri ( Lapparent , 1960 [originally Elaphrosaurus gautieri ])

Spinostropheus is a genus of theropod dinosaur from the Ceratosauria group , whichlived in Africaabout 134 to 131 million years ago during the Lower Cretaceous ( Hauterivium ). This genus is only known from eddies that originate from two sites in the early Cretaceous Tiourarén Formation in Niger . The only species, Spinostropheus gautieri , was initially assigned to the genus Elaphrosaurus , as Elaphrosaurus gautieri .

features

Spinostropheus is estimated to be four meters long. It can be distinguished from other genera by four features on the vertebrae: For example, the spinous processes were wide and rectangular; In addition, the epipophyses (processes that are located above the postzygapophyses on the back of the vertebrae) are flattened dorsoventrally .

Research history, finds and naming

The first find consists of 16 vertebrae and was discovered in 1959 in In Tedreft , which is about 250 km northwest of Agadez . In 1960 Albert-Félix de Lapparent described these fossils as a new species of the Jurassic genus Elaphrosaurus - Elaphrosaurus gautieri . With Spinostropheus, Paul Sereno and colleagues (2004) set up an independent genus for this species. These authors also described an articulated spine that comes from Fako, which is about 35 km southwest of Ingall , and assigned it as the second known fossil also Spinostropheus . This spine has been handed down from the third cervical vertebra up to and including the anterior sacral vertebrae, including cervical ribs and fragmentary back ribs. Both sites are counted as part of the Early Cretaceous Tiourarén Formation , a unit of the Tegama group .

The name Spinostropheus ( Gr. Spinos - "sting", strophe - "vertebra") indicates the pronounced epipophyses of the cervical vertebrae. The second part of the species name given by Lapparent (1960), gautieri , honors the discoverer of the site, the geologist F. Gautier.

Systematics

Ceratosauria cladogram (simplified from Xu, 2009)
Ceratosauria  Spinostropheus     Deltadromeus  unnamed  Limusaurus     Elaphrosaurus  unnamed  Ceratosaurus     Abelisauroidea
Systematic position of Spinostropheus .

Spinostropheus is considered a basal (original) representative of the Ceratosauria and is classified as such outside of the Abelisauroidea . Related genera include Ceratosaurus , Elaphrosaurus , Limusaurus, and Deltadromeus .

Individual evidence

1. ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ u. a. 2010, ISBN 978-0-691-13720-9 , p. 78, princeton.edu .
2. ↑ ^{a b c d e} Paul C. Sereno , Jeffrey A. Wilson, Jack L. Conrad: New dinosaurs link southern landmasses in the Mid-Cretaceous. In: Proceedings of the Royal Society. Series B: Biological Sciences. Vol. 271, No. 1546, 2004, ISSN 0950-1193 , pp. 1325-1330, doi : 10.1098 / rspb.2004.2692 .  
3. ^ ^{A b c} Matthew T. Carrano, Scott D. Sampson: The Phylogeny of Ceratosauria (Dinosauria: Theropoda). In: Journal of Systematic Palaeontology. Vol. 6, No. 2, 2008, ISSN  1477-2019 , pp. 183-236, doi : 10.1017 / S1477201907002246 .
4. ↑ ^{a b} Xing Xu , James M. Clark , Jinyou Mo, Jonah Choiniere, Catherine A. Forster, Gregory M. Erickson, David WE Hone, Corwin Sullivan, David A. Eberth, Sterling Nesbitt, Qi Zhao, Rene Hernandez, Cheng- kai Jia, Feng-lu Han, Yu Guo: A Jurassic ceratosaur from China helps clarify avian digital homologies. In: Nature . Vol. 459, No. 7249, 2009, pp. 940-944, doi : 10.1038 / nature08124 .