西亚试剂：A basal ichthyosauriform with a short snout from the Lower

The incompleteness of the fossil record obscures the origin of many of the more derived clades of vertebrates. One such group is the Ichthyopterygia, a clade of obligatory marine reptiles that appeared in the Early Triassic epoch, without any known intermediates1. Here we describe a basal ichthyosauriform from the upper Lower Triassic (about 248 million years ago) of China, whose primitive skeleton indicates possible amphibious habits. It is smaller than ichthyopterygians and had unusually large flippers that probably allowed limited terrestrial locomotion. It also retained characteristics of terrestrial diapsid reptiles, including a short snout and body trunk2. Unlike more-derived ichthyosauriforms3, it was probably a suction feeder. The new species supports the sister-group relationships between ichthyosauriforms and Hupehsuchia4, the two forming the Ichthyosauromorpha. Basal ichthyosauromorphs are known exclusively from south China, suggesting that the clade originated in the region, which formed a warm5, 6 and humid7 tropical archipelago8 in the Early Triassic. The oldest unequivocal record of a sauropterygian is also from the same stratigraphic unit of the region9.

以上资料由西亚试剂：http://www.xiyashiji.com/ 提供