The taxonomy, palaeobiology and taphonomy of the pterosaurs of the Kem Kem Group (Cretaceous) of southeast Morocco

Abstract

The Cretaceous Kem Kem Group Konzentrat Lagerstätten of southeast Morocco yields an incredibly diverse, but taphonomically unusual pterosaur assemblage. An examination of all pterosaur material from the Kem Kem Group has identified three new azhdarchoid taxa, bringing the total number of named pterosaurs to nine. The preservation of the pterosaur assemblage is heavily biased both taxonomically and skeletally. Comparisons with other Cretaceous pterosaur-bearing deposits including the Cambridge Greensand Member of the United Kingdom, Bissekty Formation of Uzbekistan and Javelina Formation of Texas, USA shows that the Kem Kem Group assemblage is the consequence of a unique taphonomic history. Although, the material is highly fragmentary and isolated, it is three-dimensionally preserved with excellent preservation of macro and micro internal structures. The material is dominated by edentulous jaw fragments, whilst post-cranial elements are much rarer with a complete lack of syncarpals. The overabundance of jaws is the result of a combination of factors including selective scavenging and predation, the high preservation potential of the jaw tips and possibly transportation and sorting of some elements. The assemblage is also unusual in that it yields both highly immature pterosaurs with wingspans of < 1 m and giant pterosaurs with wingspan of up to 7 m. The immature and giant forms were likely from the same species, namely Alanqa sp. and Apatorhamphus sp. This suggests that immature and mature individuals lived alongside each other and achieved this by occupying different ecological niches. It has previously been proposed that birds outcompeted small pterosaur species in the Cretaceous, however it is more likely that niches previously occupied by small pterosaur species in the Triassic and Jurassic were occupied by immature individuals of large and gigantic pterosaur taxa in the Cretaceous. The Kem Kem Group is a very important deposit for understanding pterosaur taphonomy, taxonomy and palaeobiology in the Cretaceous of North Africa. The majority of the chapters presented in this the

Date of Award	Dec 2021
Original language	English
Supervisor	David Michael Martill (Supervisor) & David Loydell (Supervisor)