A miniature notosuchian with multicuspid teeth from the Cretaceous of Morocco

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. <i>Lavocatchampsa sigogneaurussellae</i>, 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 <i>Candidodon itapecuruense, Malawisuchus mwakasyungutiensis</i>, and <i>Pakasuchus kapilimai</i>. 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 SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/ujvp 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.

产自冈瓦纳大陆（Gondwana）白垩纪陆相环境的诺托鳄类（Notosuchia），演化出了堪比哺乳动物及其已灭绝类群的多样形态构型，这一现象颇为出人意料。然而这一独特的类群多样性并不均衡：南美洲的诺托鳄类属级多样性几乎是非洲-马达加斯加的三倍。除三尖齿兽类（triconodonts）与极为特化的冈瓦纳兽类（Gondwanatheria）外，上述所有陆块中的哺乳动物均未占据主导地位，因此非洲-马达加斯加地区诺托鳄类多样性偏低的现象，似乎是采样偏差所致的假象。本文记述了一件产自摩洛哥阿尔布期-森诺曼期Kem-Kem地层的新型小型诺托鳄类，填补了这一研究空白。*Lavocatchampsa sigogneaurussellae* gen. et sp. nov. 具有全新的异型齿特征：无上颌与下颌犬齿状齿列，牙齿向后逐渐粗壮，且拥有一条尖锐延长的中脊，两侧附有两列多齿尖的齿带。通过计算机断层扫描与扫描电子显微镜（scanning electron microscopy, SEM）揭示了其咬合模式，研究显示颌骨闭合的主要运动方向为垂直方向，而非此前近缘类群研究所提出的水平方向。系统发育分析结果表明，该新分类单元属于冈瓦纳剑鼻鳄类的基干类群，与*Candidodon itapecuruense*、*Malawisuchus mwakasyungutiensis*及*Pakasuchus kapilimai*亲缘关系密切。本文修订了坎迪多鳄科（Candidodontidae）的鉴别特征，该演化支以兼具三尖齿兽类哺乳动物特征的特殊异型齿列为典型特征。对这一新演化支的确认，验证了此前提出的“连通的南美-非洲陆块存在替代分化脊椎动物组合”的假说。http://zoobank.org/urn:lsid:zoobank.org:pub:0D35356B-67FF-49A2-A518-6C19961A0894 补充数据——本文补充材料可于www.tandfonline.com/ujvp免费获取。本文引用格式：Martin, J. E., 与 F. de Lapparent de Broin. 2016. 产自摩洛哥白垩纪的多齿尖齿小型诺托鳄类. 《脊椎动物古生物学杂志》（Journal of Vertebrate Paleontology）. DOI: 10.1080/02724634.2016.1211534.