Species: Lonchopisthus micrognathus, Swordtail Jawfish

Lonchopisthus micrognathus (Poey, 1860)

Swordtail Jawfish

Elongate, compressed, tapering body; large bulbous head, eye large, high on side of head; mouth opens at front, large, extends to rear of eye; top jaw with rear end concave, a distinct hook on underside at rear; gill rakers 12-25+22-41; dorsal and anal fins with long bases; dorsal fin X-XI, 17 (16-19); anal fin III, 17 (14-18); pectoral 17-20; pelvic fins I, 5, outer 2 rays stout and unbranched, inner 3 rays weaker and branched, 2nd ray of fin a long filament, fin base before the pectoral; tail fin much longer than head, sharply pointed, no branched rays, middle 4 rays elongated, free; 47-59 longitudinal scale rows along body; cheeks scaly, rest of head scaleless; lateral line on front half of body only, high.

Pale grey-brown; head with 3 narrow blue-white bars behind eye; body with ~6-8 narrow blue-white bars at front and irregular vertical rows of blue spots at rear; dorsal and anal fins with dark blue-grey bands inside white edges; dark blotch on operculum not conspicuous if present; pelvics whitish, with dark blue-grey leading edge; tail fin grey, dark blue-grey bands inside white edges, free central filaments blue-grey; inner membrane connecting top and bottom jaws dark.

Reaches 17.8 cm.

Lives in burrows on muddy bottoms; lives commensally with a crab; often in large colonies.

Depth range: 6-265 m.

The Gulf of Mexico to Suriname