A new species of Cricosaurus (Thalattosuchia, Metriorhynchidae) based upon a remarkably well-preserved skeleton from the Upper Jurassic of Germany

Herein we describe a new and exceptionally well-preserved skeleton of the metriorhynchid thalattosuchian Cricosaurus from the upper Kimmeridgian Torleite Formation of Painten in Bavaria (Southern Germany). The specimen is articulated, shows soft -tissue preservation, and represents one of the most complete metriorhynchid skeletons known. The exceptional preservation allows us to explore the morphological variation of the tail region in the Metriorhynchidae, a part of the skeleton that has long been neglected. Based on our description and phylogenetic analyses, we name this specimen Cricosaurus albersdoerferi sp. nov. Our phylogenetic analyses recover a Cricosaurus subclade composed of four species from Southern Germany and one from Argentina. We provide revised diagnoses for the Southern German members of this subclade, revealing the presence of at least four closely-related Cricosaurus species in the upper Kimmeridgian-early Tithonian of Southern Germany. Interestingly, within this subclade there is evidence of rapid change in tail construction and feeding ecology. However, there is no evidence of sympatry between these taxa, and the two species known from the same ammonite subzone are exclusively found in different northern Tethys lagoons. Most interesting, however, is the variation in the skulls, dorsal neural spines, the tail displacement units, and flukes between these different species. This previously unexplored variation within Metriorhynchidae hints to differences in locomotory abilities between different species.