Thalattosaurs have moderate adaptations to marine lifestyles, including long, paddle-like tails and slender bodies. Primitive features of thalattosaurs include the many teeth covering the palate, single-headed ribs, and broad, plate-like coracoid bones. The most unusual features of thalattosaurs are their snouts. Members of one group, the Askeptosauroidea, have long, narrow, pointed skulls. The extended rostra at the end of the skull push back the nostrils so that they are positioned closer to the eye sockets. Most have small teeth, but one askeptosauroid, Endennasaurus, is entirely toothless. Members of a second group, Thalattosauroidea, have more distinctive downturned snouts. Clarazia and Thalattosaurus both have snouts that taper into a narrow tip. Most of the snout is straight, but pr