This shark is adapted for low oxygen environments

The Filetail catshark (Parmaturus xaniurus) is a catshark belonging to the family Scyliorhinidae. It is found ranging from Oregon to the Gulf of California. Adults are epibenthic and found near areas of rocky vertical relief over soft mud bottoms on the outer continental shelf and upper slope at depths of 299 to 4,104 feet, juveniles are mesopelagic, found around 1,608 feet off the bottom in waters over 3,281 feet deep. Filetail catsharks have enlarged gills that seem to enable them to live in low oxygenated environments.


Family: Scyliorhinidae – Catsharks

Genus: Parmaturus 

Species: xaniurus


Phylum– Chordata

Class– Chondrichthyles


Common NameGround Sharks

Family– Scyliorhinidae

Common NameCatsharks




Average Size and Length: Each egg case measures 7 x 11 cm. Adult males measure between 37-45 cm/1.2-1.5 feet. Adult females measure between 47-55 cm/1.5-1.8 feet.

Teeth and Jaw: The teeth are small, pointed or jagged with 5-7 cusps, with the central cusp the longest. Teeth in the back are the widest, while the teeth in the front are narrower.

Head: The snout is somewhat long and blunt. There are large, triangular anterior nasal flaps. There are ridges under the eyes.

Denticles: There are crests of saw-like dermal denticles along the top of the tail, but not below.

Demographic, Distribution, Habitat, Environment and Range: The Filetail catshark can be found in the northwest Pacific in the USA IN Oregon to Mexico, in the Gulf of California (39°N – 20°N). They can be found on the outer continental shelf and upper slope, much of the time on or near the bottom between 299-4,104 feet. Adults are epibenthic. Juveniles can live in midwater up to 1,068 feet above the seabed in water that is over 3,281 feet deep, being mesopelagic.

Diet: They have been observed in their natural habitat from a submersible feeding o moribund lanternfish in almost anoxic conditions. They will eat mainly pelagic crustaceans and small bony fish.

Aesthetic Identification: The Filetail catshark has a dark, plain, soft and flabby body. It is brownish-black dorsally, and a bit lighter below. The fins are dark. The gill slits are enlarged. The dorsal fins are similar in size. The origin of the first dorsal fin is slightly behind the pelvic fin origins, but well in front of the midbases. The second dorsal fin is much smaller than the anal fin, and the insertion is well in front of the anal fin insertion.

Biology and Reproduction: They are oviparous. The egg cases have “T” shaped lateral flanges and short tendrils. Females deposit egg cases throughout the year, with concentrated reproductive output July through September.

There liver is filled with squalene. Their enlarged gills may help them thrive in low-oxygen habitats.

Behavioral Traits, Sensing and Intelligence: They have been observed in their natural habitat from a submersible in almost anoxic conditions.

Their squalene-filled liver may help them remain neutrally buoyant.

Filetail Catshark Future and Conservation: They are currently of least concern. They are common among their range. They are often discarded as bycatch by bottom trawls and sablefish traps.

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