Rugops
- Niger ( Echkar Formation)
Rugops is a genus theropod dinosaur from the group of Abelisauridae. So far, a fragmentary skull is only known that from the early Late Cretaceous ( Cenomanian ) of Echkar Formation in Niger. Only species described is Rugops primus.
The name Rugops primus (Lat.: Ruga - "fold", Gr. Opsi - "face", primus - "first" ) received the kind, since it was one of the earliest Abelisauriden with a textured surface of the skull.
Discovery
Rugops was discovered by a research team led by Paul Sereno in Echkar Formation in the southern Sahara in 2000. The date the only Fund ( holotype, specimen number IGU1 MNN ) is a partially preserved skull, which is located behind the eye socket part not received for the most part. The skull could have belonged to a young animal, whereupon its small size and only partially fused suture between the left and right nasal bone points.
Features
The skull is reconstructed to a length of 31.5 cm. Rugops distinguished from related genera by an additional small skull window in the skull roof between prefrontal ( frontal ) prefrontal, postorbital and lacrimal bone ( lacrimal ) and by one row of seven small impressions on the paired nasal bone ( nasal ) on top of the snout from. He has many of basal ( primitive ) Abelisauriden typical features; the derived (modern) features the latest, highly advanced Abelisauriden the Upper Cretaceous lacking. For example, the eyebrow, which is very pronounced in advanced Abelisauriden in Rugops only rudimentary; moreover the skull of Rugops shows no horns, unlike typical skulls of advanced Abelisauridae.
Palaeobiogeography
From the discovery of Rugops and another African Ceratosauria, Spinostropheus, Paul Sereno and colleagues conduct references to former connections between continents from ( palaeobiogeography ). Sereno support the hypothesis that during the Lower Cretaceous all southern land masses except Africa were connected to each other ( Africa - fist - hypothesis ).
Rugops shows strong similarities with a 2002 in South America found more fragmented Abelisaurierfossil. This is an indication that there might have been in the early Late Cretaceous 95 million years ago a land connection between South America and Africa.
System
Rugops is considered a basal representative of the Abelisauridae. The possible systematic position of Rugops cladogram shows the following (simplified by Sereno and colleagues, 2004):
Rugops
Carnotaurinae