Dusky Catshark

This species possess the following set of characters: short and broad head, its width 13.5% TL, length 19.1% TL; short snout, broadly rounded, its length 2.5 in head length; triangular anterior nasal flaps; large mouth, its width 10.3% TL, length 4.6% TL; short labial furrows confined to mouth corners; small papillae on roof of mouth; elongate abdomen, the pectoral-pelvic space 2.8 times length of pectoral-fin anterior margin, 1.7 times interdorsal space; distance of pre-dorsal about 42% TL, 10.9 times eye length; distance of anal-caudal 6.3% TL; origin of first dorsal-fin slightly behind origin of pelvic fin, while the origin of the second is well behind anal-fin mid-base; length of anal-fin base 1.2 times the second dorsal-fin base length, subequal to interdorsal space; weakly tricuspidate flank denticles, very slender crowns, their length more than twice their width; minute teeth mainly with 4 small cusps, central pair longer than those adjacent, about 100 rows in each jaw; upright flank denticles weakly tricuspidate; precaudal centra about 93, before upper caudal-fin origin; uniformly greyish brown body (Ref. 76945).

The sombre catshark (Bythaelurus incanus) is a species of catshark in the family Scyliorhinidae. It is known from a single specimen south of Rote Island, northwestern Australia. Its natural habitat is the open seas.