Sunday, April 9, 2017

[Paleontology • 2017] Chenanisaurus barbaricus • An Abelisaurid from the latest Cretaceous (late Maastrichtian) of Morocco, North Africa

Chenanisaurus barbaricus  
 Longrich, Pereda-Suberbiola, Jalil, Khaldoune & Jourani, 2017  

During the latest Cretaceous, distinct dinosaur faunas were found in Laurasia and Gondwana. Tyrannosaurids, hadrosaurids, and ceratopsians dominated in North America and Asia, while abelisaurids and titanosaurids dominated in South America, India, and Madagascar. Little is known about dinosaur faunas from the latest Cretaceous of Africa, however. Here, a new abelisaurid theropod, Chenanisaurus barbaricus, is described from the upper Maastrichtian phosphates of the Ouled Abdoun Basin in Morocco, North Africa on the basis of a partial dentary and isolated teeth. Chenanisaurus is both one of the largest abelisaurids, and one of the youngest known African dinosaurs. Along with previously reported titanosaurid remains, Chenanisaurus documents the persistence of a classic Gondwanan abelisaurid-titanosaurid fauna in mainland Africa until just prior to the end-Cretaceous mass extinction. The animal is unusual both in terms of its large size and the unusually short and robust jaw. Although it resembles South American carnotaurines in having a deep, bowed mandible, phylogenetic analysis suggests that Chenanisaurus may represent a lineage of abelisaurids that is distinct from those previously described from the latest Cretaceous of South America, Indo-Madagascar, and Europe, consistent with the hypothesis that the fragmentation of Gondwana led to the evolution of endemic dinosaur faunas during the Late Cretaceous.

Keywords: Dinosauria; Theropoda; Ceratosauria; Abelisauridae; Gondwana; Biogeography

Fig. 3. Holotype of Chenanisaurus barbaricus, left dentary OCP DEK-GE 772.
A, lateral view, B, medial view, C, dorsal view.

Abbreviations: gr, vascular grooves; idp, interdental plates; nvf, neurovascular foramina; sd, supradentary bone; sym, symphysis; vas, vascular grooves.
DOI: 10.1016/j.cretres.2017.03.021 

Systematic paleontology
Dinosauria Owen (Owen, 1842)
Saurischia Seeley (Seeley, 1888)

Theropoda Marsh (Marsh, 1881)
Ceratosauria Marsh (Marsh, 1884)

Abelisauridae Bonaparte and Novas (Bonaparte and Novas, 1985)

Chenanisaurus barbaricus new genus and species

Etymology. The genus name refers to the Sidi Chennane phosphate mines, the type locality, and Greek ‘sauros, ‘lizard’. The species name is derived from the Greek barbaros, “savage” or “barbaric” and also refers to Barbary, a name historically used for Morocco and the northwest coast of Africa.

Diagnosis. Large abelisaurid characterized by a proportionately deep mandible, dentary bowed in lateral view, lateral groove and associated foramina located high on dentary; anterodorsal margin of dentary downturned in lateral view; massive symphysis, with anterior margin of symphysis vertical in lateral view; tip of jaws broad, with dentaries meeting at an obtuse angle.

Holotype. OCP DEK-GE 772, anterior end of the left dentary ( Fig. 3 ;  Fig. 4).

Horizon and Locality. The type specimen is reported as coming from the upper Maastrichtian (Couche III) of Sidi Chennane; the pale white color of the bone and the color of the associated matrix are consistent with the preservation seen in other material recovered from this locality. The isolated premaxillary teeth come from the upper Maastrichtian (Couche III) of Sidi Daoui. The maxillary tooth is of unknown provenance but likely comes from either Sidi Chennane or Sidi Daoui. All specimens come from the Ouled Abdoun Basin, Morocco North Africa (Fig. 1).

Fig. 9. Chenanisaurus barbaricus shown to scale with the Couche III titanosaur. 

Nicholas R. Longrich, Xabier Pereda-Suberbiola, Nour-Eddine Jalil, Fatima Khaldoune and Essaid Jourani. 2017. An Abelisaurid from the latest Cretaceous (late Maastrichtian) of Morocco, North Africa. Cretaceous Research. In Press. DOI: 10.1016/j.cretres.2017.03.021


"Chenanisaurus barbaricus" lythronax-argestes

New moderately-sized abelisaur. I thought the silhouette in the paper was too majungasaurine, so I made my own with blackjack and hookers.
Dentary line drawing from Longrich et al. (2017), silhouette from Rugops by Crizz30 on Commons, human from Andrew Farke on Phylopic as usual.