Heteroscymnoides marleyi

Author: Fowler, 1934

Field Marks:
Small size, bulbous elongated snout, no dorsal fin spine; first dorsal fin far forward, with origin over pectoral bases, second dorsal only slightly larger than first, no anal fin, dark brown colour with light-edged fins.

Diagnostic Features:
Anterior nasal flaps very short, not expanded into barbels; snout very long, bulbously conical, length almost half head length and about equal to distance from mouth to pectoral origins; gill openings very small, uniformly wide; lips thin, not fringed, pleated or suctorial; teeth strongly different in upper and lower jaws, uppers small, with narrow, acute, erect cusps and no cusplets, not bladelike, lowers much larger, bladelike, interlocked, with a high, moderately broad, semi-erect cusp and distal blade, edges no serrated; tooth rows 22/23. Both dorsal fins spineless; first dorsal well forward, origin over pectoral bases, insertion far ahead of pelvic origins and much closer to pectoral bases than pelvics; second dorsal fin slightly larger than first but with base about equal to first dorsal base; origin of second dorsal over midbase of pelvics; pectoral fins with short, narrowly rounded free rear tips and inner margins, not expanded and acute or lobate; caudal fin semisymmetrical, almost paddle-shaped, with moderately long upper lobe and well-developed lower lobe, subterminal notch strong. No precaudal pits, lateral or midventral keels on caudal peduncle. Dermal denticles flap but with pedicels, with lanceolate, ridged, wedge-shaped, monocuspidate crowns. Cloaca normal, not expanded as a luminous gland. Colour brown with conspicuous light and dark banded fin margins.

Geographical Distribution:
South central Atlantic: Near Ascension Island. Southwestern Indian Ocean: Durban, Natal, South Africa.

Habitat and Biology:
A poorly known, apparently oceanic dwarf shark; the holotype was captured off a beach but a second specimen was recently taken in the Atlantic at night between the surface and 502 m (Krefft, 1980). Mode of reproduction unknown but probably ovoviviparous and with few young. Food unknown, presumably pelagic fish and invertebrates.

Size:
Of two specimens, the 12.8 cm female holotype is immature and has an umbilical scar, indicating it is close to the size at birth; the 28.5 cm female reported by Krefft (1980) was not examined for maturity but judging from the size of the holotype and the relative size of full-term fetuses or newborn specimens and adult females in other small pelagic squaloids this specimen could very well be mature.

Interest to Fisheries: None.

Type material:
Holotype: Academy of Natural Sciences, Philadelphia, ANSP 53046, 128 mm female. Type Locality: Western Indian Ocean, Durban coast at Point Ocean Beach, Natal, South Africa.

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