Tetragonurus atlanticus

Author: Lowe, 1839

Tetragonurus atlanticus Lowe, 1839

Status in World Register of Marine Species:
Accepted name: Tetragonurus atlanticus Lowe, 1839 (updated 2009-06-25)

Diagnosis: body cylindrical, elongate. Inter-orbital distance about equal to eye diameter; snout only slightly longer than eye diameter; lower jaw shuts within the upper; lachrymal bone greatly expanded. D XIV-XVII + 10-13; A I + 9-12; P 14-18. Origin of dorsal fin ahead of posterior third of pectoral fin; origin of pelvic fin under pectoral fin base. Adherent keeled scales arranged in a geodesic pattern around body; lateral series of scales to origin of caudal keels 73-95. Vertebrae 40-51. Colour: light brown to almost black, young specimens lighter; larval specimens lack pigment at base of caudal fin. Size: to about 50 cm SL, but most encountered are much smaller.

Habitat: oceanic in warm and temperate waters, the young epipelagic and the adults presumably mesopelagic. Young commonly inquiline in pelagic tunicates, especially Salpa and Pyrosoma. Food: the teeth are especially adapted for browsing on soft-bodied medusae, ctenophores and especially salps; will also take plankton. Reproduction: spawn in the autumn in the eastern Atlantic.
Distribution: eastern Atlantic southward from southern British Isles. Elsewhere, Pacific and Indian Oceans. Nowhere abundant.

Eggs, larvae and young stages. Grey, 1955: 20-21, fig. 8-9.
Otoliths (sagitta). No data.