Besanosaurus was‭ ‬a‭ ‬primitive icthyosaur that lacked a dorsal fin and had a more eel-like tail rather than the fish-like tail seen in later more advanced genera.‭ ‬The jaws were long and thin,‭ ‬filled with small conical teeth for trapping marine organisms.‭ ‬The eyes that were around twenty centimetres in diameter may have been a deep water adaptation for seeing and hunting in the black of deep water.‭ ‬In fact,‭ ‬other shastasaurid ichthyosaurs are all envisioned as being relatively slow ‬hunters of deep water cephalopods that descend to the gloom to hide from other predators that can only see well in light conditions.‭ ‬The presence of four unborn embryos inside the type specimen of Besanosaurus not only indicates it was a female,‭ ‬but that at least some genera of ichthyosaurs were capable of giving birth to a few young. At six meters in length you might think that Besanosaurus was big,‭ ‬but in reality this was less than a third of the length of its giant relative Shastasaurus.