Belosaepia, occasionally incorrectly Belosepia,[2] is an extinct genus of cuttlefish-like cephalopod known from the Eocene.[1]
Species of the genus Belosaepia reached 18 centimetres (7.1 in) in length and 5 centimetres (2.0 in) across and had a large siphuncle that penetrated its oblique septa.[1] The shell was endogastrically coiled.[1] It had a small belemnite-like guard, which took the form of a short horn at the posterior end of the shell;[1] usually, only a small portion of the shell closest to the guard is preserved. The chambers in the shell closely resemble those present in the cuttlebone of modern cuttlefish.[1]