Species distinctions: Deep-water Spiny Dogfish:
Weight: n/a
Length: 0.45 to 0.5 m ( 18.0 to 20.0 in)
Number of young: 10 to 20
Diet: squid, crustaceans
Distinctive qualities: small shark which lives in seabed in warmer regions; single spines in front of both dorsal fins; anal fin absent; teeth of upper jaw differ from lower; black colour, velvet appearance, but rough to touch; light producing organs along underside; young born during summer months.

The deep-water spiny dogfish is a type of small shark, part of a ten species genus, which may be found at depths of 304.8 to 914.4 m (1000.0 to 3000.0 ft) in the northern regions (Iceland, Greenland) of its range or 100.0 to 200.0 m (300.0 to 600.0 ft) in the southern regions (Africa). Others have been discovered at 2000.0 m (6000.0 ft) or more. Present are single spines preceding the two dorsal fins which may cause bad wounds. The teeth found in the upper jaw differ from the lower, having three cusps- one central cusp with smaller ones on either side. The skin of the fish appears black and velvety, but is very rough in fact.

Physics Application(s):

Bioluminescence: The organs credited for bioluminescence in this species may be found along the underside of the fish, used to navigate in dark water.