Etmopterus granulosus

Author: (Günther, 1880)

Field Marks:
Two spined dorsal fins, no anal fin, bladelike unicuspidate teeth in lower jaw and teeth with cusps and cusplets in upper jaw, stocky body, conspicuous lines of denticles on body, conspicuous black markings on underside of body and tail, with tail marking short and not extending far posteriorly.

Diagnostic Features:
A moderately stout-bodies lanternshark with a short tail, distance from pelvic insertions to ventral caudal origin about as long as from tip of snout to spiracles, 1.6 times in distance between pectoral and pelvic bases, and 1.3 in interdorsal space; distance between pectoral and pelvic bases moderately long in adults, about equal to head length; distance from snout tip to first dorsal spine to second dorsal insertion. Head width about 1.3 times preoral snout; prespiracular length about 1.3 times distance from spiracles to pectoral origins; gill openings very short, about as wide as spiracle, less than 1/3 eye length; upper teeth generally with less than 3 pairs of cusplets. Origin of first dorsal fin slightly in front of free rear tinc nf nPrtnral fins firct dnrcaI base cnnsiderablv closer to Dectoral bases than pelvics; interdorsal space short, somewhat less than distance from snout tip to first gill slits; second drosal fin much larger than first; distance between second dorsal base and upper caudal origin about 2.5 in interdorsal space; caudal fin moderately long but broad, length of dorsal caudal margin about equal to distance from snout tip to pectoral midbases. Lateral trunk denticles with moderately stout, hooked conical crowns, wide-spaced and in random order on the head above the pectorals but forming regular longitudinal rows on trunk and tail; snout mostly bare of denticles, except for lateral patches; no rows of greatly enlarged denticles on flanks above pectoral fins. Distal margins of fins largely covered with skin, not fringed with naked ceratotrichia. Colour brown above, with underside of snout and abdomen abruptly black, with a short, broad black mark running above and slightly behind pelvic inner margins, and other elongated black marks at caudal fin base and along its axis.

Geographical Distribution:
Western South Atlantic: Southern Argentina, Falkland Islands/Malvinas, Straits of, Magellan. Eastern South Atlantic: Cape of Good Hope, South Africa. Eastern South Pacific: Southern Chile.

Habitat and Biology:
A little-known lanternshark of the outermost continental shelves and upper slopes at depths of 220 to 637 m. It is an unusual southern hemisphere distribution, off southern South America, the Falklands/ Malvinas Islands, and South Africa.

Size:
Males adolescent at 26 to 38 cm total length, maximum probably larger.

Interest to Fisheries:
None at present.

Remarks:
The systematic position of this species in its genus has been obscured by an error of observation on the nature of its dermal denticles dating from its original description and perpetuated in the systematic literature. I examined the holotype of E. granulosus and did not find the granular denticles supposed to characterize the species, but rather slender-cusped conical denticles partially arranged in longitudinal rows as in E. lucifer. The species is, however, easily distinguished from E. lucifer and other species with denticles in longitudinal rows. The above illustration is based on the holotype.

Type material:
Holotype: British Museum (Natural History), BMNH 1879.5.14.460, 256 mm adolescent male.Type Locality: Off Chile, 220 m depth.

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