本種には二型が認められ模様のはっきりしないものは短い頭部棘を有し,反対に模様の明瞭なものは長い頭部棘を有する傾向がある(Nelson and Nakamura, 1980)。本属の約6種のうち,C. microps, C. sadkoとC. thompsoniが本種に最も近縁と考えられる。
(中村 泉)
Material examined:
10 from Argentina (119.5-216.6 mm SL), FAKU 43074, 43165; S 377-383, 385.
Description:
D X-Y-13-14; A 11-12; P1 20-21, P2 4; BR 7; X 9+20=29.
HL 40.4-43.0% of SL; HW 30.3-36.0; ED 6.6-8.4; BD 20.3-27.3; SN 8.8-10.3; IO 7.5-9.2; UJ 15.9-21.7; CP 5.0-6.3; P1L 17.5-23.6; P2L 7.9-10.9.
Body elongate, with large, depressed head and compressed tail. Head 2.4 times in SL with many large spines. Snout short, round, its length about equal to interorbital width. Eye large, about 6 times in HL. Mouth large and oblique. Distinct frenum on lower jaw. Three pairs of pores on chin. Several rows of small recurved teeth forming tooth bands on both jaws and vomer. Pseudobranchiae present. Gill-rakers nub-like. Pectoral fin large, situated anteriorly under opercle; posterior end of pectoral fin base under posterior margin of opercle. Pelvic fin small, ventral, origin under midpectoral fin base. Dorsal fin origin close to snout than caudal fin origin. Anal fin origin under 6th to 7th ray of second dorsal fin. Anus situated at midbody, between pelvic fin origin and anal fin origin. Lateral line pores minute, surrounded by very short indistinct tubes projecting above skin surface. Color pattern on body varies very much, with or without three irregular brownish bands.
Distribution:
Off Urugay to Argentine Patagonia.
Remarks:
In this species, two forms exist, a plain-colored, short-spined form and a banded, long-spined form (Nelson and Nakamura, 1980). Of about six species of Cottunculus, this species appears to be most closely related to C. microps, C. sadko and C. thompsoni of the North Atlantic and Arctic oceans.
(Izumi NAKAMURA)
Distribution of Cottunculus granulosus in Patagonia.