|Adratiklit boulahfa |
Maidment, Raven, Ouarhache & Barrett, 2019
• Adratiklit boulahfa is a new genus of stegosaur from Morocco.
• Adratiklit is the oldest definitive stegosaur and the first from north Africa.
• It is closely related to the European stegosaurs Dacentrurus and Mirigaia.
• The dinosaur fossil record of Gondwana is biased.
• Armoured dinosaurs may have been as diverse in Gondwana as they were in Laurasia.
Eurypoda, the major radiation of armoured dinosaurs, comprises the ankylosaurs and their sister group, the stegosaurs. As the earliest-branching major clade of ornithischian dinosaurs, the evolutionary history of Eurypoda is significant for understanding both the palaeobiology of bird-hipped dinosaurs and the composition of middle Mesozoic ecosystems. Eurypodans were diverse and abundant throughout the Late Jurassic and Cretaceous in Laurasia; in contrast, their remains are extremely rare in Gondwana. Herein, we describe a new genus and species of stegosaur from the Middle Jurassic of Morocco, Adratiklit boulahfa. Adratiklit is the first eurypodan from north Africa and the oldest definitive stegosaur from anywhere in the world. The genus is more closely related to the European stegosaurs Dacentrurus and Miragaia than it is to the southern African taxa Kentrosaurus and Paranthodon. Statistically significant correlations between the number of dinosaur-bearing formations, dinosaur-bearing collections, and eurypodan occurrences in Gondwana indicates that their fossil record is biased by both geological and anthropogenic factors. Tantalizing but fragmentary remains and trackways suggest that eurypodan diversity in Gondwana may have been as rich as that of Laurasia, and the prospects for future discoveries of new genera across Gondwana are therefore very good.
Keywords: Stegosauria, Eurypoda, Morocco, Gondwana, Middle Jurassic, Diversity
|NHMUK PV R37366, holotype specimen of Adratiklit boulahfa.|
|NHMUK PV R37367, isolated cervical vertebra referred to Adratiklit boulahfa.|
Dinosauria Owen, 1842
Ornithischia Seeley, 1887
Stegosauria Marsh, 1877
Adratiklit gen. nov.
Adratiklit boulahfa gen. et sp. nov.
Holotype: A dorsal vertebra, NHMUK PV R37366.
Locality and horizon: El Mers Group, probably El Mers II Formation (Bathonian), Boulahfa, south of Boulemane, Fès-Meknes, Morocco.
Etymology: Generic name Adratiklit from ‘Adras’, Berber for ‘mountain’, and ‘tiklit’, a Berber word for lizard. The specific name, boulahfa, refers to the location where the specimen was found.
Adratiklit boulahfa is the first eurypodan thyreophoran dinosaur from North Africa, and represents one of the earliest records of this clade from anywhere in the world. Based on currently available data, it is more closely related to a clade of European stegosaurs that it is to either of the known African genera, Kentrosaurus or Paranthodon. The paucity of eurypodan dinosaur material in Gondwana during the Jurassic and Cretaceous probably results from anthropogenic and geological sampling biases, and it is possible that eurypodans might have been as diverse and abundant in Gondwana as they were in Laurasia. The prospects for finding new thyreophorans on the continents that made up Gondwana are therefore stronger than previously supposed.
Susannah C.R. Maidment, Thomas J. Raven, Driss Ouarhache and Paul M. Barrett. 2019. North Africa's First Stegosaur: Implications for Gondwanan Thyreophoran Dinosaur Diversity. Gondwana Research. In Press. DOI: 10.1016/j.gr.2019.07.007