The only shark with the combination of 5 gill slits and 1 dorsal fin

The Onefin catshark (Pentanchus profundicolus) is a species of catshark belonging to the family Scyliorhinidae. It is the only member of its genus. It is known from only 2 specimens, with the holotype found in Mindanao. No adult females have been found, so reproduction is not known.


Family: Scyliorhinidae – Catsharks

Genus: Pentanchus 

Species: profundicolus


Phylum– Chordata

Class– Chondrichthyles


Common NameGround Sharks

Family– Scyliorhinidae

Common NameCatsharks




Average Size and Length: It is known from only 2 specimens. The immature specimen was measured at 38 cm/1.2 feet. The adult male was measured at 51 cm/1.7 feet and the maximum length is unknown. 

Teeth and Jaw: The mouth is short. The labial furrows are very long, with the uppers reaching the upper symphysis. The teeth have three cusps in the upper and lower jaws, with the central cusp slightly longer than the surrounding two.

Head: The head is broadly flattened and spatulate. The snout is broadly rounded, elongated and usually longer than the with of the mouth.

Tail: The caudal fin is without a crest of denticles, but has a distinct subterminal notch.

Demographic, Distribution, Habitat, Environment and Range: The Onefin catshark can be found in the northwest Pacific in the Philippines. Theholotype was found in the Tablas Straits and Mindanao, and just east of Bohol (12°N – 8°N). They have been found in deep water, on the insular slope, on the bottom between 2,208-3,510 feet and are considered bathydemersal.

Aesthetic Identification: The Onefin catshark is plain brownish in color. It is the only species with the combination of five gill slits and one dorsal fin. It has an unusually short abdomen. The pectoral and pelvic fins are very close together. It has a very long and low anal fin.

Biology and Reproduction: Reproduction is unknown because no adult females have been found.

Behavioral Traits, Sensing and Intelligence: Unknown.

Onefin Catshark Future and Conservation: There is currently not enough data to evaluate. They are only known from two specimens.

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