Species: Nicholsina usta, Emerald Parrotfish

Nicholsina usta (Valenciennes in Cuvier & Valenciennes, 1840)

Emerald Parrotfish

Body elongate, robust; snout relatively long, front head profile straight; a small cirrus at edge of front nostril; teeth not fused into a beak, free, with flattened pointed tips, in 2-7 overlapping rows; without canines on side of rear of top jaw; large crushing plates of molar teeth form “pharyngeal mill” in throat; gill membranes with free fold of skin at midline under throat; dorsal fin IX, 10, no notch between spines and rays; anal fin III, 9; pectoral rays 13; scales large, smooth; median predorsal scales 4-5; a single row of 4-5 scales on cheek below eye; lateral line in 2 sections.

Initial phase: pale greyish brown, sometimes with 2 broad dark stripes along mid-side and back; Terminal phase: mottled greenish on back, head under mouth yellow; two diagonal red & blue stripes on cheek (one from eye to rear of mouth); a diagonal blue bar from top of eye to center of mouth; a blue spot immediately behind eye; iris red; body scales with short blue bars; dorsal, tail and anal fins with irregular network of red lines.

Size: to about 30 cm.

Habitat: common on algal-covered reefs, and on rubble bottoms with sufficient shelter, also on seagrass beds.

Depth: 1-73 m.

New Jersey to Brazil.

Note: Its sister species are N. collettei from the E Atlantic, and N. denticulata from the E Pacific.