Asperoris
| Asperoris | |
|---|---|
| |
| Front part of the skull | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Archosauromorpha |
| Clade: | Crocopoda
|
| Clade: | Archosauriformes |
| Genus: | †Asperoris Nesbitt et al., 2013 |
| Type species | |
| †Asperoris mnyama Nesbitt et al., 2013
| |
Asperoris is an
Manda Beds of southwestern Tanzania. It is the first archosauriform known from the Manda Beds that is not an archosaur. However, its relationships with other non-archosaurian archosauriforms are uncertain. It was first named by Sterling J. Nesbitt, Richard J. Butler and David J. Gower in 2013 and the type species is Asperoris mnyama. Asperoris means "rough face" in Latin, referring to the distinctive rough texture of its skull bones.[1]
Discovery
Asperoris is known solely from the well-preserved but incomplete
generic name is derived from asper, meaning "rough", and oris, meaning "face" in Latin in reference to its rough and uniquely sculptured skull. The specific name mnyama means "beast" in Swahili.[1]
Description
Like most archosauriforms from the Manda Beds, Asperoris is known from very fragmentary remains. NHMUK PV R36615 is distinguished from some other archosauriform material in the beds by the lack of a depression called an
antorbital fossa on the surfaces of its maxilla and premaxilla. Although it can not be directly compared with Stagonosuchus, Hypselorhachis, Nyasasaurus, Teleocrater and an unnamed suchian, its inferred phylogenetic position is not consistent with it belonging to any of these taxa. The total length of the skull is estimated to have been 50 centimetres (20 in) in length. A unique characteristic or autapomorphy of Asperoris is the rough texture of its skull bones, particularly the frontal. The skull roof of Asperoris is relatively thick compared to those of other archosauriforms and its antorbital fenestra, a hole in the side of the skull in front of the eye socket, is relatively narrow.[1]
Relationships
Asperoris belongs to a
proterosuchids, and is characteristic of the clade.[1]
Because of the poor preservation of NHMUK PV R36615 and the
plesiomorphies).[1]
Asperoris was also featured in a phylogenetic analysis by
Martin Ezcurra in 2016. Most parts of Ezcurra's analysis omitted this genus due to its incompleteness, but in versions which did feature it, it was found in a polytomy with Yarasuchus, Dongusuchus, Dorosuchus, and Euparkeria at the base of a clade which also includes proterochampsians and archosaurs. Ezcurra named this broad clade Eucrocopoda. The five-genus polytomy is resolved into a clearer system of clades when Asperoris is omitted, as the taxon's lack of postcranial features reduced the analysis's clarity.[2] Yarasuchus and Dongusuchus are now considered to be aphanosaurs, part of a group of archosaurs at the base of the branch that leads to pterosaurs and dinosaurs (including birds) but not crocodiles.[3]