Author: Regan, 1906
Field Marks:
Dark brown or blackish coloration, no anal fin, dorsal fins with fairly prominent fin spines, moderately long snout, lanceolate upper teeth and bladelike lower teeth with short, oblique cusps, stocky body that tapers abruptly from pectoral region, and moderately large tricuspidate and tricarinate lateral trunk denticles.
Diagnostic Features:
Body stocky, strongly tapering back from pectoral region. Snout moderately long, preoral length about equal to distance from mouth to first gill slits and equal to mouth width; lips thick and fleshy; upper labial furrows very short, their lengths much less than distance between their front ends; lower teeth with short, oblique cusps and moderately high, fairly broad roots. Second dorsal fin somewhat higher than first, fin spines stout and with at least a third of their lengths protruding from fins; first dorsal fid not extending forwards as a prominent ridge, origin over pectoral bases; second dorsal base about as long as space between it and upper caudal origin, free rear tip well in front of unner caudal origin: pectoral fins large, apices falling about opposite first dorsal spine when laid back; free rear tips of pelvic fins falling well in front of second dorsal insertion. Lateral trunk denticles large, with strong triple ridges and cusps in the holotype and only extant specimen.
Geographical Distribution:
Western South Atlantic: Straits of Magellan.
Habitat and Biology:
A poorly known deepwater dogfish, known at present only from the holotype from the Straits of Magellan, depth not recorded.
Size:
The holotype and only known specimen is 68 cm long; presumably the species attains a larger size than this, but this is uncertain.
Interest to Fisheries: None.
Remarks:
The writer examined the holotype in the British Museum (Natural History), upon which the illustration and present account is based. Lonnberg (1907) described Etmopterus paessleri from Smyth Channel in the Straits of Magellan, from three small syntypes deposited in the Zoologisches Museum of the University of Hamburg. These are apparently lost (Krefft, 1968a), but Lonnberg presented a photograph in dorsal view of one of the syntypes. This species was accepted as an aberrant species of Etmopterus by Regan (1908d), Garman (1913), and Bigelow and Schroeder (1957), but careful consideration of Lonnberg's description, measurements and illustration, and a lateral-view reconstruction made from this information, caused the writer to strongly suspect that Etmopterus paessleri is a junior synonym of Centroscymnus macracanthus. Particularly the broad head, large pectoral fins, large broad caudal fin, upper teeth without lateral cusplets, denticles with lateral cusps, and second dorsal spine slightly smaller than first, as well as the general morphology of E. paessleri all fit C. macracanthus as studied from the holotype. Hence this species is placed in tentative synonymy of C. macracanthus.
Type material:
Holotype: British Museum (Natural History) BMNH-1184.2.6.7, 680 mm female. Type Locality: "Magellan" (Straits of Magellan).