Stocky and dark brown in color, the Portuguese dogfish can be distinguished from similar-looking species (such as the kitefin shark, Dalatias licha) by the small spines in front of its dorsal fins.

This species typically reaches 0.9–1 m (3.0–3.3 ft) in length; sharks in the Mediterranean Sea are much smaller and have distinct depth and food preferences.

Valued for its liver oil and to a lesser extent meat, Portuguese dogfish are important to deepwater commercial fisheries operating off Portugal, the British Isles, Japan, and Australia.

These fishing pressures and the low reproductive rate of this species have led the International Union for Conservation of Nature (IUCN) to assess it as Near Threatened.

[2] They created the new genus Centroscymnus for this shark, and gave it the specific epithet coelolepis, derived from the Greek koilos ("hollow") and lepis ("fish scale") and referring to the structure of the dermal denticles.

The lower teeth have a short, strongly angled cusp and number 29–41 rows; their bases interlock to form a continuous cutting surface.

[2] The very large dermal denticles change in shape with age: in juveniles, they are widely spaced and heart-shaped with an incomplete midline ridge and three posterior points, while in adults they are overlapping, roughly circular, smooth, and flattened with a round central concavity, superficially resembling the scales of bony fishes.

[17] Living almost exclusively in the aphotic zone where little to no sunlight penetrates, the Portuguese dogfish is relatively common and the dominant shark species in deeper waters.

[18] A tracking study in the Porcupine Seabight has found that the Portuguese dogfish has an average swimming speed of 0.072 m/s (0.24 ft/s), and does not remain in any particular area for long.

[22] An active predator of mobile, relatively large organisms, the Portuguese dogfish feeds mainly on cephalopods (including Mastigoteuthis spp.)

The visual system of this species appears adapted for detecting bioluminescence: the maximum absorption of its opsins correspond to the wavelengths of light emitted by favored prey, such as the squids Heteroteuthis dispar, Histioteuthis spp., Lycoteuthis lorigera, and Taningia danae.

[4] The smaller size of Mediterranean sharks relative to those from the rest of the world may be due to limited food availability and/or the warmer, saltier environment.

Bony fishes are a secondary food source, while immature sharks favor the shrimp Acanthephyra eximia, the most common decapod crustacean in their environment.

[12] Figueiredo et al. (2008) reported that there are two breeding seasons per year off Portugal, from January to May and from August to December, with only a fraction of the population reproductively active at a time.

[13] Studies of females have found no traces of sperm inside their reproductive tracts, which suggests that fertilization occurs immediately following copulation, which may also trigger ovulation.

[1][7] An important fishery for the Portuguese dogfish exists in Suruga Bay for liver oil; catches peaked during World War II, but declined soon after from over-exploitation.

[1] In the past few years, catches by the South East Trawl Fishery off Australia have been increasing, as fishers have been seeking out species not covered by commercial quotas following the relaxation of seafood mercury regulations.

[1] Around 1990, French bottom trawlers began to fish for Portuguese dogfish and leafscale gulper sharks (Centrophorus squamosus) west of the British Isles for meat and livers; these two species are together referred to as siki.

The French have since been joined by Norwegian, Irish, and Scottish longliners and trawlers, making the Portuguese dogfish a significant component of deepwater fisheries in the northwest Atlantic.