Eotyrannus
Partial skeleton of the holotype MIWG 1997.550
- England (Isle of Wight )
- Eotyrannus Lengi
Eotyrannus is a generic theropod dinosaur from the Lower Cretaceous of Europe and an early ancestor of Tyrannosaurus rex. This genus is the Tyrannosauroideen found a lineage within the Coelurosauria. The only kind and type species, Eotyrannus Lengi, is known from a skeleton got to 40 percent, which was in the south of England (Isle of Wight ) found and probably from the Lower Cretaceous ( Barremian ) comes.
Eotyrannus was four to five feet long and, like most theropods running a bipedal carnivore. The genus name Eotyrannus means as much as " formerly tyrant " or " tyrant of the Dawn ", while the Artepitheth Lengi the fossil collector Gavin Leng honors, who discovered the skeleton in 1996. In 2001 published Hutt, Naish, Martill, Barker and Newbery, the first scientific description of this animal.
Discovery
The only skeleton ( catalog number MIWG1997.550 ) comes from the southwest coast of the Isle of Wight and belongs stratigraphically to the Wessex Formation, a layer of rock within the Wealden Group. It consists of a partial skull (including Zwischenkieferbein, a partial upper jaw ( maxilla ), the nasal bone, the quadrate, the dentary, the lacrimal bone ( lacrimal ) and teeth ), elements of the body axis (including neck, back, and possibly caudal vertebrae ), scapula, coracoid, some arm bone ( humerus including, possibly ulna, and hand bones ) and some leg bones (including tibia, fibula, and foot bones ).
Features
Eotyrannus has a number of features which have been demonstrated in other Tyrannosauroideen such as Tyrannosaurus ( synapomorphies ). As for example, were the teeth of the intermediate jaw bone in the front part of the upper jaw and lower different shape ( the cross-section was "D" - or "U" -shape ) than the remaining teeth ( Heterodontie ). In addition, the paired nasal bone was fused and showed a rough surface.
The arms and especially hands were at Eotyrannus compared with other theropods exceptionally long, similar to other early Tyrannosauroideen such as guanlong. So the second finger reached 95 percent of the length of the humerus. Later tyrannosaurids such as Tyrannosaurus had in contrast, extremely atrophied arms and hands. Unlike the later tyrannosaurids the third finger was not back yet formed at Eotyrannus. Since the skeleton was found only slightly ossified, it is assumed that it has traded at a juvenile ( juvenile ) specimen.