Homalocephale

Live reconstruction of Homalocephale

• Mongolia, China

Homalocephale is a genus of bird Beck dinosaur ( Ornithischia ) from the group of Pachycephalosauria. He was one of the flat -headed representatives of this group, at the same time he is one of the most completely preserved Pachycephalosauriern. Only species described is H. calathocercos.

Features

Homalocephale reached a length of about 3 meters, making it one of the medium sized Pachycephalosauriern. Like all members of this group had this dinosaur on a strikingly thickened skull roof, from the frontal bone ( frontal ) and the parietal ( parietal ) was formed. He counts to the flat -headed representatives of this group, in which the skull roof is not bulged, the cranial sutures visible and the upper cranial window the temporal region was well developed. To speculate on the function of this cranium see function of the cranial vault in the Pachycephalosauria. In addition, small bony protuberances were present on the side and rear parts of the skull. The obtained upper teeth were small and contributed triangular crowns. Like all Pachycephalosaurier Homalocephale likely to have fed mainly vegetable, possibly supplemented by insects.

In contrast to most other Pachycephalosauriern also the fuselage skeleton is well preserved. The fuselage was relatively stocky, the vertebrae were reinforced by interlocking connections that the sacrum fused sacral vertebrae showed long ribs ( sacral ribs) on. The anterior caudal vertebrae were also equipped with fins posterior caudal vertebrae were stiffened by chevron bones (V- shaped extensions at the bottom) and ossified tendons. The pool was built very wide; the hind legs were long and suggest that this dinosaur could move relatively quickly.

Discovery and designation

The fossil remains of Homalocephale were discovered in the Mongolian province Ömnö Gobi aimag and 1974 first described, other findings are from the Chinese province of Tibet. The genus name is derived from the Greek words homalos ( = 'equal' ) and kephale ( = " head"), a common name component of Pachycephalosauriern, from. Type species and only known species is H. calathocercos. The finds are (late Campanian or early Maastrichtian ) dated to the Late Cretaceous to an age of around 76-69 million years.

System

Traditionally Homalocephale the group of primitive, flat face was representative within the Pachycephalosauria in the Homalocephalidae, incorporated, which were named after this dinosaur and who faced the dome- headed, highly developed Pachycephalosauridae. The " Homalocephalidae " apply today however as paraphyletic, so do not represent a natural affinity group, as the Pachycephalosauridae have developed from them. A cladistic analysis of T. Maryańska et al. Homalocephale sees as relatively primitive representatives of Pachycephalosauria. With the discovery of Dracorex, a flat face, but sophisticated Pachycephalosaurier, the internal system is, however, falter. According to R. Sullivan, it is also conceivable that the development of dome -headed was too flat -headed animals, so the flat skull is the derived feature.