A miniature notosuchian with multicuspid teeth from the Cretaceous of Morocco

ABSTRACT

Notosuchians from Cretaceous continental environments of Gondwana have developed an unexpected array of morphologies comparable to mammals and their extinct relatives. However, this exceptional diversity is unbalanced, with South America holding nearly three times the generic diversity of Africa-Madagascar. With the exception of the triconodonts and of a very specialized group, the Gondwanatheria, in none of these landmasses do mammals dominate, and as a result, the low notosuchian diversity in Africa-Madagascar appears to be an artifact of sampling. Here, we describe a new miniature notosuchian from the Albian-Cenomanian Kem-Kem Beds of Morocco filling this gap. Lavocatchampsa sigogneaurussellae, gen. et sp. nov., exhibits a new type of heterodonty with absence of maxillary and dentary caniniform dentitions and teeth that gradually become massive posteriorly, and possess a sharp elongate median carina flanked by two multicusped cingula. The occlusion pattern is revealed by computed tomography and scanning electron microscopy (SEM) and shows that the main component of jaw closure is vertical, and not horizontal as has been proposed in closely related forms. Phylogenetic analysis recovers the new taxon as part of a basal stock of Gondwanan ziphosuchians with close affinities to Candidodon itapecuruense, Malawisuchus mwakasyungutiensis, and Pakasuchus kapilimai. We revise the diagnosis of Candidodontidae, a clade characterized by a particular heterodont dentition recalling that of triconodont mammals. The recognition of this new clade confirms previous hypotheses of a vicariant vertebrate assemblage present on a continuous South American–African landmass.

http://zoobank.org/urn:lsid:zoobank.org:pub:0D35356B-67FF-49A2-A518-6C19961A0894

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Citation for this article: Martin, J. E., and F. de Lapparent de Broin. 2016. A miniature notosuchian with multicuspid teeth from the Cretaceous of Morocco. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1211534.

ACKNOWLEDGMENTS

We thank the following individuals: B. Fectay and C. Bidaut (‘La Mémoire de la Terre,’ Aumont) and D. E. Russell and D. Sigogneau-Russell (MNHN, Paris) (discovery and purchase); J. F. Bonaparte (Buenos Aires), Z. Gasparini and M. de la Fuente (La Plata), and P. M. Brito (Rio de Janeiro) (documentation and comparative collections); F. Renoult, B. Battail, and R. Allain (MNHN Paris; comparative collections); C. Weber Chancogne (MNHN Paris; SEM); D. Serrette (MNHN Paris; initial photographs); F. Pilard (MNHN Paris; initial drawing); P. Vincent (MNHN Paris); and R. Amiot and E. Mattioli (LGLTPE, Lyon). C. Charles (IGFL, ENS Lyon) provided much helpful technical assistance with the CT scans. CT scans were financially supported by the Laboratoire de Géologie de Lyon: Terre, Planète, Environnement (LGLTPE, UMR CNRS 5276). Finally, we thank the two reviewers, A. Ősi and D. Pol, as well as the editor A. Turner for their comments, which helped improve the quality of the manuscript.