Rugops

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Rugops
Reconstructed skull of Rugops

Reconstructed skull of Rugops

Temporal occurrence
Upper Cretaceous ( Cenomanium )
100.5 to 93.9 million years
Locations
Systematics
Lizard dinosaur (Saurischia)
Theropoda
Ceratosauria
Abelisauroidea
Abelisauridae
Rugops
Scientific name
Rugops
Sereno et al., 2004

Rugops is a genus of theropod dinosaur from the group of Abelisauridae . So far, only a fragmentary skull is known from the early Upper Cretaceous ( Cenomanium ) of the Echkar Formation in Niger . The only species described is Rugops primus .

The name Rugops primus ( Latin : Ruga - "fold", Gr .: Opsi - "face", primus - "first") got the species because it was one of the earliest Abelisaurids with a textured skull surface.

Find

Rugops was discovered in 2000 in the Echkar Formation in the southern Sahara by a team of researchers led by Paul Sereno . The only find so far ( holotype , specimen number MNN IGU1) is a partially preserved skull, the part behind the eye socket has largely not been preserved. The skull could have belonged to a young animal, as indicated by its small size and the only partially fused suture between the left and right nasal bones.

features

The skull is reconstructed to a length of 31.5 cm. Rugops is distinguished from related genera by an additional small skull window in the roof of the skull between the frontal bone (frontal), prefrontal, postorbital and tearbone (lacrimal) as well as by a row of seven small impressions each on the pair of nasal bones (nasals) on the top of the muzzle. It has many characteristics typical of basal (more primitive) Abelisaurids; however, the derived (modern) features of the last, very advanced Abelisaurids of the Upper Cretaceous are missing. For example, the eyebrow, which is very pronounced in advanced Abelisaurids, is only rudimentary in Rugops ; Furthermore, the skull of Rugops does not show any horns, in contrast to typical skulls of the advanced Abelisauridae.

Paleobiogeography

From the discovery of Rugops and another African Ceratosauria , Spinostropheus , Paul Sereno and colleagues derive clues about connections between continents at that time (paleobiogeography). Sereno supports the hypothesis that during the Lower Cretaceous all southern land masses except Africa were connected to one another ( Africa-fist-hypothesis ).

Rugops shows strong similarities with a more fragmented abelisaur fossil found in South America in 2002 . This is an indication that there could have been a land connection between South America and Africa as early as the early Upper Cretaceous 95 million years ago.

Systematics

Rugops is considered a basic representative of the Abelisauridae. The possible systematic position of Rugops is shown in the following cladogram (simplified from Sereno and colleagues, 2004):

  Abelisauridae  

 Rugops 


   

 Abelisaurus 


   

Carnotaurinae




Template: Klade / Maintenance / Style

Individual evidence

  1. ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 79, online .
  2. ↑ a b c d e f g Paul Sereno , Jeffrey A. Wilson, Jack L. Conrad: New dinosaurs link southern landmasses in the Mid-Cretaceous. Proceedings of the Royal Society. Series B: Biological Sciences. Vol. 271, No. 1546, 2004, ISSN  0080-4649 , pp. 1325-1330, doi : 10.1098 / rspb.2004.2692 .
  3. ^ Paul Sereno: Rugops primus - The First Wrinkle Face. In: Paul Sereno - Paleontologist. Archived from the original on October 2, 2010 ; accessed on August 7, 2014 .
  4. ^ 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, here p. 197, doi : 10.1017 / S1477201907002246 .

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