Aldrovandia affinis

Author: Günther, 1877

Aldrovandia affinis (Gunther, 1877)

Status in World Register of Marine Species:
Accepted name: Aldrovandia affinis (Günther, 1877) (updated 2009-06-25)

Diagnosis: preoral portion of snout long, contained about two times in total snout length. Dorsal finrays 11-13; ventral finrays I + 8; pectoral finrays I + 11-14. First ray of dorsal fin very short and spine-like. Pectoral fin short and fairly broad, falling well short of origin of ventral fin. Dorsal and pelvic fins inserted nearly opposite each other. Top of snout and head scaleless, opercle scaleless. Palatine tooth patches in contact medially. Anterior gill arch with 13-15 rakers. Preanal lateral line scales 25-31; lateral line fairly indistinct, unpigmented. Pyloric caeca in a single row, black, 6-9. Colour: white to light brown; gill isthmus, branchiostegal membranes, opercular membranes and underside of body dark. Size: to about 55 cm (gnathoproctal length to about 20 cm).

Habitat: benthopelagic on the middle and lower slope (700-2,200 m), occurring primarily above the 4° C isotherm. Behaviour: hovers within a few metres of substrate, parallel to it or inclined at varying angles. Food: polychaetes, pelecypods, amphipods and other benthic prey. Reproduction: spawning appears to be seasonal and out of phase with sympatric congeners. In the western North Atlantic a female to male sex ratio of about 2:1 has been determined. Sexually dimorphic: males with mature gonads have enlarged posterior nostrils, dark tubular anterior nostrils and dark pigmentation on the top of the snout.

Distribution: known from off Madeira. Elsewhere, circumglobal at temperate and tropical latitudes except for eastern Pacific.

Eggs, larvae and young stages. The halosaurid leptocephalus described by Harrisson (1966) might be A. affinis (cf. Harrisson, 1972: 558), a species of which a specimen is known from Northwest Africa (McDowell in Harrisson, 1972: 558).
Otoliths (sagitta). No data.