Castellanos and Menni (1969); Okutani (1980); Roper et al. (1969, 1984).
(畑中 寛)
Material examined:
FSFL EL 735, EL 736, EL 909, EL 916, EL 964, EM 190, EM 211, EM 467, EM 468 (9 specimens, 168-300 mm ML)
Description:
Mantle cylindrical, robust. Fins triangular; length 39-43%, width 50-62% of dorsal mantle length (ML); fin angle 47°-52°. Head width about 17% of ML. Funnel-mantle rocking apparatus T-shaped; no vertical fold (foveora) nor side pocket in funnel groove. Eyes without cornea, in open contact with seawater. No hooks on arms, suckers in 2 rows; sucker rings with several teeth, distal median tooth enlarged; left or right arm ? of mature male hectocotylised, modified tip (lamellae) 28-56% of the arm length. Tentacles relativery short; clubs long, 31-39% of ML, suckers in 4 rows and enlarged in medial 2 rows on mid part of clubs (nanus), 2 rows at basal part (carpus), many minute suckers at the tip (dactylus). Color reddish brown, darker along dorsal midline of mantle. Attains 40 cm ML.
Distribution:
Known from the Atlantic coast of South America south of Uruguay. Common on the continental shelf and slope in the Argentine waters.
Remarks:
Genus Illex differs from other genera of Ommastrephidae in having smooth funnel groove without foveora and side pocket. I. argentinus is quite similar to I. illecebrous norphologically, but their habitats not overlapped.