Montefeltro Felipe C, Larsson Hans C E, de França Marco A G, Langer Max C
Laboratório de Paleontologia de Ribeirão Preto, FFCLRP, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901 Ribeirão Preto, SP, Brazil.
Naturwissenschaften. 2013 Sep;100(9):835-41. doi: 10.1007/s00114-013-1083-9. Epub 2013 Jul 27.
Phylogenetic relationships near the origin of extant crocodylians are weakly supported, and this lack of resolution makes for poor estimates of taxonomic and morphological diversity. Previously known taxa are found throughout the Cretaceous in Laurasia and at a few sites from Brazil, Australia, and northern Africa. Here, we report Batrachomimus pastosbonensis gen. et sp. nov. from the Late Jurassic of northeastern Brazil, which is deeply nested within Neosuchia and associated to the Cretaceous Asian paralligatorids. The new taxon predates all other members of Paralligatoridae and its immediate sister group (including Eusuchia) by 30 million years. A nearly complete skull, osteoderms, and limb bones were recovered, and autapomorphies of B. pastosbonensis include a scalloped lateral margin of the rostrum in dorsal view, unsculpted alveolar margin at the caudalmost portion of the maxilla, blunt lateral prongs on the jugal at the base of the postorbital bar, hourglass shaped choanae, and pterygoid choanal septum extended between the palatal shelves of the palatines. The crocodyloid-like skull proportions and the slender, conical teeth suggest an amphibious and piscivorous life history to this 1 m long animal.
现存鳄形类动物起源附近的系统发育关系支持力度较弱,这种缺乏分辨率的情况导致对分类学和形态多样性的估计不佳。以前已知的类群在整个白垩纪的劳亚大陆以及巴西、澳大利亚和北非的一些地点都有发现。在此,我们报告来自巴西东北部晚侏罗世的巴氏蛙鳄(Batrachomimus pastosbonensis)新属新种,它深深嵌套在新鳄类中,并与白垩纪亚洲近鳄科动物相关。这个新类群比近鳄科的所有其他成员及其直接姐妹群(包括真鳄类)早3000万年。我们发现了一个近乎完整的头骨、骨板和四肢骨骼,巴氏蛙鳄的自近裔性状包括:从背面看,吻部侧面边缘呈扇形;上颌最尾端部分的牙槽边缘无雕刻;眶后棒基部的颧骨上有钝的外侧叉;鼻孔呈沙漏形;翼骨鼻孔隔板在腭骨的腭架之间延伸。这种类似鳄形类的头骨比例以及细长的锥形牙齿表明,这种1米长的动物具有两栖和食鱼的生活史。