Zanno Lindsay E, Drymala Susan, Nesbitt Sterling J, Schneider Vincent P
1] Research &Collections, North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA [2] Department of Biological Sciences, North Carolina State University, Raleigh, NC 27607, USA.
Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Sci Rep. 2015 Mar 19;5:9276. doi: 10.1038/srep09276.
Triassic predatory guild evolution reflects a period of ecological flux spurred by the catastrophic end-Permian mass extinction and terminating with the global ecological dominance of dinosaurs in the early Jurassic. In responding to this dynamic ecospace, terrestrial predator diversity attained new levels, prompting unique trophic webs with a seeming overabundance of carnivorous taxa and the evolution of entirely new predatory clades. Key among these was Crocodylomorpha, the largest living reptiles and only one of two archosaurian lineages that survive to the present day. In contrast to their existing role as top, semi-aquatic predators, the earliest crocodylomorphs were generally small-bodied, terrestrial faunivores, occupying subsidiary (meso) predator roles. Here we describe Carnufex carolinensis a new, unexpectedly large-bodied taxon with a slender and ornamented skull from the Carnian Pekin Formation (~231 Ma), representing one of the oldest and earliest diverging crocodylomorphs described to date. Carnufex bridges a problematic gap in the early evolution of pseudosuchians by spanning key transitions in bauplan evolution and body mass near the origin of Crocodylomorpha. With a skull length of >50 cm, the new taxon documents a rare instance of crocodylomorphs ascending to top-tier predator guilds in the equatorial regions of Pangea prior to the dominance of dinosaurs.
三叠纪捕食者群落的演化反映了一个生态动荡时期，这一时期由二叠纪末的灾难性大灭绝引发，并在侏罗纪早期恐龙在全球生态中占据主导地位时结束。为了应对这种动态的生态空间，陆地捕食者的多样性达到了新的水平，促使形成了独特的营养网络，其中食肉类群似乎过多，还演化出了全新的捕食类群。其中关键的是鳄形超目，它们是现存最大的爬行动物，也是至今仍存活的两个主龙类谱系之一。与它们如今作为顶级半水生捕食者的角色不同，最早的鳄形超目动物通常体型较小，是陆地食兽动物，扮演着次要（中等）捕食者的角色。在这里，我们描述了卡罗琳卡尼弗克斯，这是一种来自卡尼阶佩金组（约2.31亿年前）的新的、体型意外庞大的类群，其头骨细长且有纹饰，它代表了迄今为止所描述的最古老且分化最早的鳄形超目动物之一。卡尼弗克斯跨越了伪鳄类早期演化中一个有问题的空白，它经历了鳄形超目起源附近身体结构演化和体重的关键转变。这个新类群头骨长度超过50厘米，记录了在恐龙占主导地位之前，鳄形超目动物在泛大陆赤道地区上升到顶级捕食者群落的罕见实例。
