Despite the very ancient origins of this genus and its abundance in the fossil record, phylogenetic evidence indicates that all extant species in the genus arose from a single common ancestor that survived the Cretaceous-Paleogene extinction, with diversification into modern species only starting around the mid-Eocene.

[1] Bullhead sharks have tapered bodies, with most species reaching around 70–130 centimetres (2.3–4.3 ft) in length.

[4] Bullhead sharks live in coastal littoral environments,[1] generally shallower than 100 metres (330 ft), and are usually primarily active at night.

[7][8] Hatchlings are considered large for sharks, reaching over 14 cm in length by the time they leave the egg case.

[8] The egg case of the Mexican hornshark features a tendril and more rigid flanges, suggesting that egg case design of this species primarily involves anchoring with tendrils rather than wedging into crevices.