Rugops

Rugops (meaning 'wrinkle face') is a monospecific genus of basal abelisaurid theropod dinosaur from Niger that lived during the Late Cretaceous period (Cenomanian stage, ~95 Ma) in what is now the Echkar Formation.

The formation has also yielded specimens pertaining to the carcharodontosaurid Carcharodontosaurus iguidensis,[3] the spinosaurid Spinosaurus,[1] an unnamed rebbachisaurid and titanosaur,[1] and the crocodylomorphs Fortignathus,[4] Laganosuchus and Kaprosuchus.

[1] The type specimen may represent a subadult individual based on its small size, the lack of fusion between the nasals and the presence of the fenestra between the prefrontal, frontal, postorbital and lacrimal bones.

The maxilla shares some similarities with Rugops such as with the morphology of the teeth, the shape of the alveolar, the rugose texture on the lateral sides, the straight border with the premaxilla, and the position of the palatal shelf.

[1] As in other abelisaurids, the skull of Rugops has an external surface that is textured, a dental arcade that is U-shaped, maxillary-jugal contact that is broad, the presence of a socket on the maxilla and alveoli that are subrectangular in shape.

[6] Sereno et al. (2004) suggested that the depressions on the dorsal surface of each nasal anchored either sensory structures or soft tissues for display.

The author suggested that, based on the type specimen probably being a subadult individual, the armour-like dermis may have reached a larger surface as it grew to which it developed a more papillate texture.

[1][13] In Rugops, the interdenticular sulci of the denticles, the presence of which might possible be a synapomorphic characteristic of Abelisauridae, is absent and has a higher dental formulae than in any other abelisaurid.

[23] Eoabelisaurus Spectrovenator Rugops Arcovenator Rajasaurus Majungasaurus Indosaurus Abelisaurus Skorpiovenator Ekrixinatosaurus Ilokelesia Dahalokely Carnotaurus Aucasaurus Rahiolisaurus The results of an earlier analysis by Pol & Rauhut (2012) are reproduced below.

[19] Berberosaurus Deltadromeus Spinostropheus Limusaurus Elaphrosaurus Ceratosaurus Genyodectes Laevisuchus Masiakasaurus Noasaurus Velocisaurus Eoabelisaurus Rugops Abelisaurus Majungasaurus Indosaurus Rajasaurus Ilokelesia Ekrixinatosaurus Skorpiovenator Carnotaurus Aucasaurus

Skeletal diagram of the holotype and only known specimen: MNN IGU1
Size compared to a human
Skull diagram and holotype maxilla