Japanese Roughshark

The Japanese roughshark (Oxynotus japonicus) is a rare species of shark in the family Oxynotidae, known only from a handful of specimens recovered from Suruga Bay and the Enshunada Sea off Japan. It is a benthic species that occurs at a depth of 150–350 m (490–1,150 ft). This shark is caught (and discarded) as bycatch by bottom trawlers throughout its entire limited range, and may be threatened given the declines in other bottom deep sea species in Suruga Bay.

This species grows to 64.5 cm (25.4 in) long. It is similar to other rough sharks in having a stout, high trunk, a dorsally depressed head, and two sail-like dorsal fins with deeply embedded spines. The snout is short, with large nostrils whose lateral and medial apertures are separated by a thick nasal flap. The eyes and spiracles are oval in shape. The five pairs of gill slits are very small and vertical. The mouth is small, with thick, fleshy lips; the teeth in the upper jaw are narrow, erect, and smooth-edged, while those in the lower jaw are broad, blade-like, and smooth-edged. Only one row of teeth in the lower jaw are functional.