Raoellidae

Raoellidae, previously grouped within Helohyidae, is an extinct family of semiaquatic digitigrade artiodactyls in the clade Whippomorpha. Fossils of raoellids are found in Eocene strata of South and Southeast Asia.

An exceptionally complete skeleton of Indohyus from Kashmir suggests that raoellids are the "missing link" sister group to whales (Cetacea). All other Artiodactyla are relatives of these two groups. δO¹⁸ values and osteosclerotic bones indicate that the raccoon-like Indohyus was habitually aquatic, but δC¹³ values suggest it rarely fed in the water. The authors suggest that this documents an intermediate step in the transition back to water completed by the whales.