Genus: Castorocauda JI, LUO, YUAN & TABRUM, 2006
Etymology: Latin, Castro, 'beaver', and Latin, cauda, 'tail': after the broad, flattened, scaly, and beaver-like tail for swimming.
Species: lutrasimilis JI, LUO, YUAN & TABRUM, 2006
Etymology: Latin, lutra, 'otter', Latin, simils, 'similar': Similar to extanct otters in some dental and vertebral characters.
Locality: Daohugou locality, N41°18.979', E119°14.318', Ningcheng County, Inner Mongolia.
Horizon: Jiulongshan Fromation.
Age: Middle Jurassic.
Material: An incomplete, flattend skeleton, partial skull and partial skeleton.
Note: With scales and fur.