Universidade Federal do Rio de Janeiro, Laboratório de Sistemática e Tafonomia de Vertebrados Fósseis (LAPUG), Departamento de Geologia e Paleontologia, Museu Nacional, Quinta da Boa Vista, s/n, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil.
Universidade Federal do Espírito Santo, Departamento de Biologia, Alto Universitário, s/n, Guararema, 29500-000 Alegre, ES, Brazil.
An Acad Bras Cienc. 2023 Aug 14;95(suppl 1):e20230179. doi: 10.1590/0001-3765202320230179. eCollection 2023.
Notosuchian crocodyliforms were major components of the South American Cretaceous biota and, for over 125 years, paleontological fieldwork in this continent recovered several well-preserved fossils of these animals. They are largely recognized for terrestrial life and specialized feeding habits, frequently presenting bizarre taxa such as Comahuesuchus. A new species, Comahuesuchus bonapartei n. sp. (MUCPv 597; cast MN), is described from geological strata of Sierra Barrosa Formation (Upper Turonian) and Portezuelo Formation (Lower Coniacian) of Lake Barreales, Patagonia, Argentina. The new fossil comprises a right dentary bone that shares important and unique anatomical features with specimens of Comahuesuchus brachybuccalis, such as the presence of a well-marked shelf on the lateral surface of the bone; a flat, low, and wide mandibular symphysis; an enlarged, labiolingually compressed caniniform tooth at caudal position in the dentary; the presence of serrated mesial and distal carinae in the caniniform with a faceted labial surface, and the absence or extremely reduction in number of the postcaniniform dentition. C. bonapartei differs from C. brachybuccalis in having individual dentary alveoli, rather a dentition set in groove. Phylogenetic analyses support a sister-relationship between both species, which are well nested within notosuchians.
正鳄形超目鳄形类动物是南美白垩纪生物群的主要组成部分，在过去的 125 年里，在这个大陆的古生物学野外工作中，已经发现了几种保存完好的这些动物化石。它们主要以陆地生活和专门的摄食习惯而闻名，经常出现像 Comahuesuchus 这样奇异的分类群。一种新的物种，Comahuesuchus bonapartei n. sp.（MUCPv 597；铸型 MN），是从阿根廷巴雷雷斯湖的 Sierra Barrosa 组（上 Turonian）和 Portezuelo 组（下 Coniacian）的地质地层中描述的。新化石由一个右齿骨组成，它与 Comahuesuchus brachybuccalis 的标本具有重要而独特的解剖特征，例如骨的外侧表面有明显的架子；平坦、低而宽的下颌联合；在齿骨的尾部位置有一个增大的、唇舌向压缩的犬齿状牙齿；在犬齿状上有锯齿状的近侧和远侧齿嵴，具有有面的唇面，以及后犬齿状齿列的缺失或极度减少。C. bonapartei 与 C. brachybuccalis 的区别在于，它有单个的齿骨牙槽，而不是在凹槽中的齿列。系统发育分析支持这两个物种是姐妹关系，它们很好地嵌套在正鳄形类中。
