Rytiodus (meaning Rytina, "wrinkled", an old name for Steller's sea cow)[1] is an extinct genus of sirenian, whose fossils have been discovered in France, Europe and Libya.

With a length of 6 m (20 ft), Rytiodus was about twice the size as modern sirenians, surpassed only by Steller's sea cow, which was up to 8–9 m (26–30 ft) long.

Like its closest modern relatives, the dugongs, Rytiodus had a pair of flippers, a streamlined body and a tail fin.

Its flattened snout allowed it to feed in shallow coastal waters.

Rytiodus had short tusks which it may have used to extract food from the sand.