The phylogenetic affinities of Afromimus tenerensis Sereno, 2017

CERRONI, M.A.; AGNOLÍN, F.L.; BRISSON EGLI, F.; NOVAS, F.E.

Congreso; Jornadas Argentinas de Paleontología de Vertebrados XXXII; 2018

Afromimus tenerensis Sereno, 2017 was recently described on the basis of an incomplete skeleton coming from the LowerCretaceous of Niger. The specimen was originally described as a basal ornithomimosaur. This clade of dinosaurs is abundantin Laurasia, and thus, its record in Gondwana has deep biogeographical implicances. However, an overview of thedescription of the specimen indicates that it may belong to Abelisauroidea. It shares with the latter clade: tibia with fibularcrest continuous with proximal end, large elliptical scar on posterior surface of the tibia (absent in ornithomimosaurs),relatively low ascending process of the astragalus, which is sub-rectangular in contour, large iliofibular tubercle of fibula,pedal phalanx with lateral bump and ?V?-shaped lateral furrows and lacking flexor tubercle, distal caudal vertebrae with excavatedfossae for prezygapophyses (convergently acquired with ornithomimosaurs), and chevrons anteroposteriorlynarrow with fused pedicels. These features are present in several ceratosaurs such as Ceratosaurus Marsh, 1884 andabelisauroids (e.g., Skorpiovenator Canale et al., 2008). A noticeable feature of Afromimus shared with some abelisauroids,is that distal caudal centrum bears a cranial surface wider than high; also present in Elaphrosaurus Janensch, 1920 and LigabueinoBonaparte, 1996. A phylogenetic analysis was conducted using Winclada based on the data matrix of Carrano etal. (2012) to test the phylogenetical position of Afromimus among theropods. A strict consensus tree recovered Afromimusas an abelisauroid, particularly as the sister-taxon of Masiakasaurus Sampson et al., 2001. This result is similar to that convergentlyacquired by Cau, pers. com. (2018).