本種は北米東岸からカリブ海にかけて分布するM. auratusとは第1背鰭条数(8本)および第1背鰭の縞によって区別される(Hubbs and Marini, 1935)。
(稲田伊史)
Material examined:
4 from Argentina (97.2-155.8 mm SL), FSFL EL 774; EM 229, 230, 508.
Description:
D Z, T, 8; A U, 6; P1 15-17; P2 T, 5; LLS 34; GR 5-7+11-14=17-21.
HL 28.2-30.0% of SL; ED 6.7-7.9; BD 27.9-30.0; SN 11.4-12.1; IO 7.3-8.6; JD 10.0-10.9; CP 10.7-11.9; P1L 23.1-25.0; P2L 21.9-23.6; Barbel L 19.0-21.4.
Body oblong, deep, slightly compressed. Snout blunt, steep, high; dorsal profile of head gradually arched downward before dorsal fin becoming abruptly declivitous on snout. Eye large. Interorbital space wide, convex. Mouth large and horizontal; lower jaw more inferior than upper; posterior end of upper jaw reaching to below anterior eye margin, at least in adults. Round-tipped teeth in one series on lower jaw, with a few smaller teeth forming an incipient second row. No teeth on upper jaw. Palatine with a pair of large patches of submolar teeth. No spine on opercular margin and no serration on preopercular margin. Caudal fin deeply forked. Two long barbels on chin extending posterior to posterior margin of preopercle at their tips. Upper part of body reddish, lower part pinkish. A large blotch or band of jet black near tip of first dorsal fin. Three bands on second dorsal fin. Posterior median rays of caudal fin blackish, both lobes with indistinct bands. Pectoral and pelvic fins reddish. Anal fin rays pale pinkish, its membrane translucent, and its base milky white. Cheek and preopercle silvery white.
Distribution:
Coasts from Uruguay to northern part of Argentina in depths of 20-60 m.
Remarks:
This species is distinguished from M. auratus, Which is known from the east coast of North America and the Carribean Sea, by the number of 1st dorsal fin rays and the color of fins (Hubbs and Marini, 1935).