Revision of the Late Jurassic deep-water teleosauroid crocodylomorph Hulke, 1871 and evidence of pelagic adaptations in Teleosauroidea.

Teleosauroids were a successful group of semi-aquatic crocodylomorphs that were an integral part of coastal marine/lagoonal faunas during the Jurassic. Their fossil record suggests that the group declined in diversity and abundance in deep water deposits during the Late Jurassic. One of the few known teleosauroid species from the deeper water horizons of the well-known Kimmeridge Clay Formation is '' Hulke, 1871, a poorly studied, gracile longirostrine form. The holotype is an incomplete snout from the Sub-Boreal ammonite Zone of Kimmeridge, England. The only other referred specimen is an almost complete skull from the slightly older Sub-Boreal ammonite Zone of Quercy, France. Recently, the validity of this species has been called into question. Here we re-describe the holotype as well as the referred French specimen and another incomplete teleosauroid, DORCM G.05067i-v (an anterior rostrum with three osteoderms and an isolated tooth crown), from the same horizon and locality as the holotype. We demonstrate that all specimens are referable to '' and that the species is indeed a valid taxon, which we assign to a new monotypic genus, In our phylogenetic analysis, the latest iteration of the ongoing Crocodylomorph SuperMatrix Project, is found as sister taxon to within a subclade containing and . Notably has an extreme reduction in dermatocranial ornamentation and osteoderm size, thickness and ornamentation. These features are mirrored in , a species with a well-preserved post-cranial skeleton and a similar shallow and inconspicuous dermal ornamentation. Based on these morphological features, and sedimentological evidence, we hypothesise that the + clade is the first known teleosauroid lineage that evolved a more pelagic lifestyle.