Protoichthyosaurus

Protoichthyosaurus is a genus of ichthyosaur from the Early Jurassic of southern England and possibly Switzerland. First described by Robert M. Appleby in 1979, the taxon was regarded as a junior synonym of Ichthyosaurus between 1997 and 2003. Its validity was restored following a revision published in 2017, which identified several anatomical differences, notably in the arrangement and morphology of the carpal bones, as well as the absence of a fifth digit. Two species are currently recognized: the type species P. prostaxalis and P. applebyi, the latter being described in the 2017 revision. However, that same revision removed a third species originally assigned to the genus, P. prosostealis, due to its similarity to Ichthyosaurus. The species most likely lived during the Hettangian stage, but may have lived as early as the Rhaetian and as late as the Sinemurian.