This is a little-studied deep-water species that lives on continental slopes in the Indo-Western Pacific from Malaysia and Borneo to the north to Saruga Bay (Japan), off the coast of Brunei , China , Kalimantan , Japan and the Philippines . Keeps at a depth of about 759 m.
In 1999, Nakaya and Sato divided the genus Apristurus into three groups: longicephalus (2 species), brunneus (20 species) and spongiceps (10 species). The flat-headed black feline shark belongs to the brunneus group, the representatives of which are characterized by the following features: short, wide muzzle, from 13 to 22 spiral intestinal valves , upper lip sulcus much longer than the bottom; intermittent supraorbital sensory canal. The color is black, brown or gray, fins without edging [2] .
The maximum fixed size is 80 cm. Sexual maturity occurs at a length of 60 cm. The flat-headed black feline shark has a short belly - the distance between the pectoral and ventral fins is less than 3/5 of the length of the base of the anal fin. The first dorsal fin is smaller than the second. Anal fin is short and long [3] . The diet consists of crustaceans , squid and small fish. Propagated by laying eggs enclosed in a hard capsule. The fibrous capsule is thin, cylindrical, devoid of processes and filaments. The absence of threads may indicate that females are carrying eggs inside their bodies.
Occasionally caught as by-catch in deep-sea nets. Data to assess the state of conservation of the species is not enough [4] .
