The crocodiles of the Jurassic Sea, the steneosaurs, were inhabitants of the offshore sea and of river deltas. Only fully grown animals ventured out far into the open sea. Their body form resembles that of today’s gavias.
During the Jurassic, the coast which had to be visited for the purpose of laying eggs was approximately 150 kilometres east of present-day Holzmaden. It is for this reason that young animals less than two metres in length are very seldom found in the Holzmaden shale quarries. The largest of these marine crocodiles could reach a body length of up to seven metres.