FOSSIL COMPLETENESS OF THE THALATTOSUCHIA

Among the crocodilians, the extinct Thallatosuchia (Reptilia: Teleosauridae and Metriorynchidae) are noted for their adaptations to the marine environment. This group of marine reptiles ranges from the Lower Jurassic to the Lower Cretaceous and are mostly diverse in European sediments. They have been a focus of much recent phylogenetic reclassification and research into their macroevolution. However, as with marine reptiles in general, little is known about the effect of sampling biases on the thalattosuchian fossil record. Here, we report skeletal completeness and phylogenetic completeness metrics for the Thalattosuchia.

The status of the thalattosuchian fossil record was evaluated after a thorough review of the primary literature as well as examination of material in European museums. Specimen skeletal and phylogenetic completeness metrics were scored and then compared to thalattosuchian diversity, facies and lithology type, environmental variables, and intrinsic variables such as body size. Completeness scores were analysed over a geologic time-series. These comparisons are analysed with respect to various European Lagerstätten in order to discover whether named Lagerstätten truly consist of fossils of superior quality, thus offering greater insight into past life.