Article: An ichthyosaur with preserved soft tissue from the Sinemurian of southern England

A new specimen of ichthyosaur in a carbonate concretion from the Sinemurian (Lower Jurassic) of Black Ven, near Charmouth, Dorset, shows soft tissue preservation. The specimen is indeterminable at generic and specific level. It comprises the posterior portion of the axial skeleton and displays a lunate caudal fin preserved as an organic film. A thin band of phosphatized muscle tissue in the dorsal lobe of the tail indicates that some control of fin attitude was possible despite the absence of axial skeleton in the dorsal lobe. This is the earliest record of an ichthyosaur with an indisputable complete lunate caudal fin. There was a progressive increase in the angle of downturn of the vertebral column in the ichthyosaur tail, from aproximately 25° in the new specimen, to approximately 80° in Late Jurassic ichthyosaurs. Ichthyosaurs did not possess typical reptilian epidermal scales.