Middling thread herring
soft rays: 12 - 23. Body moderately deep and compressed; posterior edge of gill openings with two clearly visible, fleshy, protuberances; gill rakers numerous, 41 to 69 on ceratobranchial (in fish longer than 14 cm total length); last dorsal ray elongated and filamentous; back gray-green with silver-white flanks and a black spot behind the gill slit followed by a yellow lateral strip (Ref. 55763). The filamentous last dorsal fin ray distinguishes it from members of any other eastern Pacific clupeoid genus. Separated from other eastern Pacific Opisthonema by having 41 to 69 lower gill rakers in fishes over 14 cm standard length.