Friday, November 10, 2017

[Paleontology • 2016] Lavocatchampsa sigogneaurusselae • A Miniature Notosuchian with Multicuspid Teeth from the Cretaceous of Morocco

Lavocatchampsa sigogneaurusselae
Martin  & de Lapparent de Broin. 2016

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 sigogneaurusselae, 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.



CROCODILIA Gmelin, 1789, sensu Martin and Benton, 2008
MESOEUCROCODYLIA Whetstone and Whybrow, 1983
NOTOSUCHIA Gasparini, 1971
ZIPHOSUCHIA Ortega, Gasparini, Buscalioni, and Calvo, 2000
CANDIDODONTIDAE Carvalho, Ribeiro, and Avilla, 2004


Etymology:— The genus name honors the memory of the French paleontologist René Lavocat (1909–2007) for his contribution to vertebrate paleontology in Africa and in particular for the exploration of the Kem-Kem Beds and the discovery of its vertebrate fossil fauna. The specific name honors Dr. Denise Sigogneau-Russell, specialist on early mammals and with her husband, Dr. Donald Russell, for the acquisition of the specimen from Bruno Fectay.

  Jeremy E. Martin and France de Lapparent de Broin. 2016. A Miniature Notosuchian with Multicuspid Teeth from the Cretaceous of Morocco. Journal of Vertebrate Paleontology.  36(6);   DOI:  10.1080/02724634.2016.1211534

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