Nyasasaurus
- Manda banks ( Tanzania)
- Nyasasaurus parringtoni Nesbitt et al., 2013
Nyasasaurus is a genus of extinct reptiles from the Middle Triassic of East Africa. Fossils of about two to three meters long animal was found in the area around today's Lake Malawi and are about 240 to 245 million years old (late Anisian ). They came for the first time in the 1930s when paleontological excavations brought to light and were asked parringtoni 2013 by a group of scientists to Sterling Nesbitt in a separate genus with the only kind Nyasasaurus. Phylogenetic analyzes of fossil material Nyasasaurus organize either as a dinosaur or as closest relatives of this group of animals. His African origin can be an origin of the dinosaurs in the southern Pangaea suspect, because the species is about 15 million years older than the previously oldest known dinosaur from the early Late Triassic of South America.
Features
Since few and fragmented fossils were found by Nyasasaurus, few morphological features of animals can be observed. The dimensions of the vertebrae suggest a body length of 2-3 m. The upper arm of Nyasasaurus had a prolonged bone crest at its upper end. The animals had at least three sacral vertebrae and had Hyposphen - Hypantrum connections between the Vorlendenwirbeln. Compared to primitive Dinosauriformen pointed Nyasasaurus on an accelerated bone growth, which is comparable to that of the early dinosaurs.
Locality, fossil material and stratigraphy
The first finds of Nyasasaurus, three neck and two back vertebrae are from the early 1930s. Gordon Murray Stockley found in the western banks of the Manda - Ruhuhu Basin in south-west Tanzania. The holotype of the species (inventory number NHMUK R6856 ) was exposed by Francis Rex Parrington in Lifua - layer member of the Manda - benches. It consists of an upper arm bone, three fragmentary back and three sacrum vertebrae. The type locality is ( approximately 240-245 mya ) dated to the late Anisian, so it belongs in the Middle Triassic. This Nyasasaurus is 10-15 million years older than Eoraptor, one of the oldest known dinosaur from the Ischigualasto Formation in Argentina.
Ecology
Since neither the skull nor the running apparatus of Nyasasaurus is known, no conclusions about his diet or lifestyle can be drawn. The large animal fauna of its habitat consisted among other things of the Cynodonten Aleodon brachyrhamphus and Scalenodon angustifrons, the Dicynodonten Sangusaurus edentatus and Angonisaurus cruickshanki and the Rhynchosaurier Stenaulorhynchus stockleyi.
System
Pseudosuchia
Pterosaur ( Pterosauria )
Lagerpetidae
Silesauridae
Nyasasaurus
Bird Beck dinosaur ( Ornithischia )
Lizards Beck dinosaurs ( Saurischia )
The first time was one of today Nyasasaurus attributed fossils in 1932 by Sydney H. Haughton as "? Thecodontosaurus alophos " written volatile. Alan Charig described in 1956 in his dissertation (doctoral thesis ) with another copy and put it in a systematic absconditum near the Prestosuchiers Spondylosoma. However charig also noticed certain similarities in bone structure with the lizards and dinosaurs Beck led the material eleven years later under the name Nyasasaurus parringtonis as relatives of Thecodontosaurus. Neither Haughton still Charig described their taxa, however, formally valid, which is why they are regarded as nomina nuda. In the following period, the fossils were performed either as Prosauropode, as early representative of the dinosaurs, or as one of their early relatives. 2013 delivered Sterling Nesbitt, Paul M. Barrett, Sarah Werning and Christian Sidor after a revision of the material and a formal diagnosis and described it under the name originally proposed by Charig. The genus name Nyasasaurus ( "lizard from Lake Nyasa " ) is based on the locality near Lake Malawi ( Lake Nyasa in Tanzania called ) that the specific epithet honors Francis Rex Parrington parringtoni, the finder of the holotype.
In addition, Nesbitt and colleagues come to the conclusion that it is either the basalsten dinosaurs or the sister taxon of this group at Nyasasaurus. In particular, the bone crest on the upper arm there is a common feature of the dinosaurs. However, the analysis of osteological features fine Nyasasaurus for individual features from sometimes as derived partly as basal dinosaurs. Provisional organize Nesbitt and colleagues the genus as dinosaurs, but also expressed reservations, because the derived and original features of the dinosaurs and the position of some other basal taxa are unclear.