The hooktooth dogfish, Aculeola nigra, is a small, little-known dogfish, the only member of the genus Aculeola.
The type specimen is held at the National Natural History Museum, Santiago, Chile.
The hooktooth dogfish has a blunt, flattened snout, very large eyes, a relatively long distance from the eye to the first gill slit, small grooved dorsal spines, a first dorsal fin about halfway between the pectoral and pelvic fins, and a broad caudal fin. They are black with a maximum length of only 60 cm.
They are found in the eastern South Pacific along the coast of South America from Peru to central Chile.
This shark is a little-known, yet common, shark that lives at depths between 110 and 560 m. They are ovoviviparous, with at least three pups per litter. They probably eat bony fish and invertebrates.