Friday, November 26, 2021

[Paleontology • 2021] Spicomellus afer • Bizarre Dermal Armour suggests the First African Ankylosaur


Spicomellus afer 
Maidment, Strachan, Ouarhache, Scheyer, Brown, Fernandez, Johanson, Raven & Barrett, 2021


Abstract
Ankylosauria is a diverse clade of armoured dinosaurs whose members were important constituents of many Cretaceous faunas. Phylogenetic analyses imply that the clade diverged from its sister taxon, Stegosauria, during the late Early Jurassic, but the fossil records of both clades are sparse until the Late Jurassic (~150 million years ago). Moreover, Ankylosauria is almost entirely restricted to former Laurasian continents, with only a single valid Gondwanan taxon. Spicomellus afer gen. et sp. nov. appears to represent the earliest-known ankylosaur and the first to be named from Africa, from the Middle Jurassic (Bathonian–Callovian) of Morocco, filling an important gap in dinosaur evolution. The specimen consists of a rib with spiked dermal armour fused to its dorsal surface, an unprecedented morphology among extinct and extant vertebrates. The specimen reveals an unrealized morphological diversity of armoured dinosaurs during their early evolution, and implies the presence of an important but undiscovered Gondwanan fossil record.


Dinosauria Owen, 18427
Ornithischia Seeley, 18878
Ankylosauria Osborn, 19239

Spicomellus afer gen. et sp. nov.

Etymology: Spicus meaning spike (Latin); mellus, a collar with spikes (Latin). A reference to the morphology of the specimen. Afer (Latin), an inhabitant of Africa. 

 
Susannah C. R. Maidment, Sarah J. Strachan, Driss Ouarhache, Torsten M. Scheyer, Emily E. Brown, Vincent Fernandez, Zerina Johanson, Thomas J. Raven and Paul M. Barrett. 2021. Bizarre Dermal Armour suggests the First African Ankylosaur. Nature Ecology & Evolution. DOI: 10.1038/s41559-021-01553-6