鉴别 |
Can be diagnosed from all congeners by the possession in all but the smallest examined specimens of a midlateral spot of dark pigmentation in the region ventral to the dorsal fin, with the spot when present ranging in intensity from a diffuse concentration of dark chromatophores in smaller specimens to a distinct black spot in the larger examined individuals. Can be further separated from many congeners by its pigmentation features which include the presence of a dark, midlateral somewhat longitudinally-ovoid spot on the posterior portion of the caudal peduncle and scales overlying the basal portions of the middle caudal-fin rays; the absence of a series of dark stripes running between the scale rows; the lack of a patch of dark pigmentation on the dorsal fin; the hyaline or lightly speckled adipose fin. Further differs meristically from various other congeners in the number of lateral line scales 29 to 31; the number of scales above the lateral line 5; the number of scales below the lateral line 4 or 5, and the number of vertebrae 31 or 32 (Ref. 90234). |