Author: Rafinesque, 1810
Field Marks:
Moderate snout, upper teeth with cusp and cusplets, lower teeth bladelike, no anal fin, second dorsal fin and fin spine larger than first dorsal fin and spine.
Diagnostic Features:
Anterior nasal flaps short, not expanded into barbels; snout short to moderately elongated, flattened or subconical, length half head length or less and subequal to or less than distance from mouth to pectoral origins; gill openings small to moderately broad and about equally wide; lips thin, not fringed or pleated, not suctorial; teeth strongly different in upper and lower jaws, uppers small, with narrow erect cusps and mesial and distal cusplets, not bladelike, lowers larger, bladelike, interlocked, with a short, narrow, oblique cusp and distal blade; tooth rows 18 to 38/24 to 52. Both dorsal fins with grooved spines, the second very large, strongly curved, and elongated, the first short but strong; first dorsal origin varying from over inner margins of pectorals to well posterior to pectoral free rear tips, insertion well anterior to pelvic origins and varying from about equidistant between pectoral and pelvic bases or closer to pectorals; second dorsal fin considerably larger than first, its base up to twice length of first dorsal base; pectoral fins with broadly rounded free rear tips, not broadly lobate or acutely attenuate; caudal fin asymmetrical, not paddle-shaped, upper lobe long, lower lobe hardly differentiated or short, subterminal notch well-developed. No precaudal pits or lateral keels on caudal peduncle. Dermal denticles either with stout to slender pedicels and acute, erect, narrow, ridged thornlike crowns or very flat and blocklike, with truncated crowns. Cloaca without a luminous gland. Colour variable, from blackish to tan, often with prominent dark markings on underside of head and caudal peduncle.
Remarks:
The arrangement of species follows Bigelow and Schroeder (1957) in many particulars. Several of the species are poorly known and are of uncertain validity and the present arrangement must be considered as highly tentative. Several new species await description, including a long-snouted pusillus-like lanternshark from near Japan (Nakaya in Okamura, Amaoka and Mitani, 1982), at least one new species from the western Atlantic (S. Springer, pers. comm.), and possibly one or more from the eastern Pacific. Etmopterus paessleri Lonnberg, 1907 is generally placed in this genus, but consideration of its characters led me to place it in tentative synonymy of Centroscymnus macracanthus (see Remarks under that species). The vernacular name 'lantern shark' indicates the minute photophores of these sharks, also found in the closely related Centroscyllium.