Another newly described catshark

The Sombre catshark (Bythaelurus incanus) is a species of shark belonging to the family Scyliorhinidae. It is known from a single specimen south of Rote Island, northwestern Australia.


Family: Scyliorhinidae – Catsharks

Genus: Bythaelurus 

Species: incanus


Phylum– Chordata

Class– Chondrichthyles


Common NameGround Sharks

Family– Scyliorhinidae

Common NameCatsharks




Average Size and Length: The recorded length of an immature male was 45.4 cm/1.5 feet.

Teeth and Jaw: The mouth is large, the width is 10.3% of the total length, and a length of 4.6% of the total length. There are short labial furrows confined to mouth corners. There are small papillae on roof of the mouth. There are minute teeth mainly with 4 small cusps, central pair longer than those adjacent, about 100 rows in each jaw.

Head: The head of the Sombre catshark is short and broad, with a width of 13.5% of the total length, and a length of 19.1% of the total length. The snout is short and broadly rounded, length 2.5 in HL. The anterior nasal flaps are triangular.

Denticles: The flank denticles are weakly tricuspidate, with very slender crowns, their length more than twice their width. The upright flank denticles are weakly tricuspidate.

Demographic, Distribution, Habitat, Environment and Range: A single specimen of the Sombre catshark was found south of Rote Island in northwestern Australia. The Sombre catshark is known only from a single immature male collected from deep water off Ashmore Reef (13°06’S, 122°18’E) in the Timor Sea at a depth between 2,953-3,281 feet.

Aesthetic Identification: The Sombre catshark is a uniformly greyish catshark. The abdomen is elongate, the pectoral-pelvic space is 2.8 times length of pectoral-fin anterior margin, 1.7 times interdorsal space. The distance of the pre-dorsal is about 42% of the total length, 10.9 times eye length. The distance of anal-caudal is 6.3% of the total length. The origin of the first dorsal-fin is slightly behind the origin of the pelvic fin. The origin of the second dorsal fin is well behind the anal-fin mid-base. The length of the anal-fin base is 1.2 times the length of the second dorsal-fin base, which is subequal to the interdorsal space. The precaudal centra is about 93, before upper caudal-fin origin.

Biology and Reproduction: Unknown but possibly oviparous.

Behavioral Traits, Sensing and Intelligence: Unknown.

Sombre Catshark Future and Conservation: There is not enough data to evaluate.

Sombre Catshark Recorded Attacks on Humans: Not a threat to humans.