Author: Smith and Radcliffe, 1912
If its unidorsate condition is normal, this is the only shark with 5 pairs of gill slits and one dorsal fin. It otherwise resembles Apristurus herklotsi.
Essentially those of Apristurus, but without a first dorsal fin (possibly abnormal, Radcliffe). Body not tadpole-shaped, stocky and compressed, increasing in height up to the pectoral and trunk region and tapering posteriorly; body soft and flabby, with thin skin and weakly calcified dermal denticles; stomach probably not inflatable; tail short, length from vent to lower caudal origin about 3/5 of snout-vent length. Head greatly depressed, pointed and wedge-shaped in lateral view; head elongated, but slightly less than 1/4 of total length (adult male); snout elongated, its length greater than mouth width, greatly flattened, narrow and pointed in lateral view; snout expanded laterally, narrowly spatulate and bell-shaped in dorsoventral view; ampullal pores enlarged and prominent on snout; nostrils enlarged, with incurrent and excurrent apertures broadly open to exterior; anterior nasal flaps reduced to angular lobes, without barbels, widely separate from each other and falling far anterior to mouth; internarial space 0.9 times in nostril width; no nasoral grooves; eyes dorsolateral on head, broad subocular ridges present below eyes; mouth broadly arched, with lower symphysis well behind upper so that upper teeth are exposed in ventral view; labial furrows present along both upper and lower jaws; these long and reaching to level of upper symphysis of mouth; branchial region not greatly enlarged, distance from spiracles to fifth gill slits less than half head length; gill slits lateral on head. Origin of second dorsal fin about over the anal midbase; pectoral fin width less than mouth width; inner margins of pelvic fins not fused over claspers in adult males; claspers short, thick, and distally pointed, not extending more than 2/ 3 of their length behind the pelvic fin tips; anal fin enlarged and greatly elongated, larger than pelvic fins and dorsal fin, base length over twice second dorsal base; origin of anal just behind pelvic bases, and insertion separated from lower caudal origin by a narrow notch; caudal fin elongated, over a fourth of total length. No crests of enlarged denticles on the caudal margins; supraorbital crests absent from cranium. No colour pattern, uniformly dark brown.
Western North Pacific: The Philippines (Mindanao Sea).
Habitat and Biology:
A poorly known deepwater bottom-dwelling shark inhabiting the insular slopes of the Mindanao Sea.
The holotype and only known specimen is a 508 mm adult male.
Interest to Fisheries:
See discussion above under the genus Pentanchus for notes on the possible synonymy of Apristurus herklotsi with P. profundicolus. The illustration is taken from the holotype.
Holotype: U.S. National Museum of Natural History, USNM 70260, 508 (now 495)mm adult male. Type Locality: Between Mindanao and Leyte Islands, Mindanao Sea, the Philippines, 10°02'N, 125°19.3'E, 1070 m.