A little-known catshark

The Dusky Snout catshark (Bythaelurus naylori) is a shark belonging to the family Scyliorhinidae. It was found from the southwest Indian Ridge, in the southwestern Indian Ocean, and other records note northwestern Australia. Perhaps a lot more data and research are needed to understand this more recently discovered species.


Family: Scyliorhinidae – Catsharks

Genus: Bythaelurus 

Species: naylori


Phylum– Chordata

Class– Chondrichthyles


Common NameGround Sharks

Family– Scyliorhinidae

Common NameCatsharks


Speciesnaylori (previously sp. A)


Average Size and Length: Immature males measure at 44 cm/1.4 feet. The maximum recorded length for a male was 51.1 cm/1.7 feet and 54.8/1.8 feet for a female.

Teeth and Jaw: The teeth have 4 cusps of about equal size, all straight and pointed. They appear burr like. They do not have oral papillae on the roof of their mouth or tongue.

Head: The head is broad and flattened. The snout is short and rounded. The preoral length is between 4.2-5.5% of the total length. The eyes appear cat-like in appearance.

Denticles: They have bristly skin. This species can be distinguished from its two closest family members, The Galapagos catshark and the Mud catshark by having a combination of prominent comb-like dermal denticles along the upper caudal-fin margin.

Demographic, Distribution, Habitat, Environment and Range: The Dusky Snout catshark can be found in northwestern Australia and known from the southwest Indian Ridge, southwestern Indian Ocean (33°S – 37°S, 55°E – 56°E). They can be found over the continental slope around 2,953 feet. One of the more recently collected specimens was collected at 292 feet. The deepest so far as been 4,734 feet.

Aesthetic Identification: The Dusky Snout catshark is uniform dark greyish-brown in color with a few pale blotches ventrally. There may be light fin edges present. The snout is noticeably dark and dusky. The body is long and soft. The back appears to be rounded upward into a hump well before reaching the first dorsal fin. The 2 dorsal fins are similar in size, well separated, and are tall and rounded. The base of the first dorsal fin is over the pelvic bases. The second dorsal fin base is over the anal fin. The anal-fin base length is equal to or less than 1.5 times second dorsal-fin base length.

Biology and Reproduction: Unknown, but thought to be oviparous.

Behavioral Traits, Sensing and Intelligence: Unknown.

Dusky Snout Catshark Future and Conservation: Not evaluated. They seem to be found in waters much too deep for commercial fisheries to be caught on a regular basis or to be in any threat. However, a more recent specimen was collected at 292 feet from a midwater trawler, and the first specimen was caught by a bottom trawler. We have much to learn about this shark.

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