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Species: Lonchopisthus micrognathus, Swordtail Jawfish

All Families:   All Genera:   All Species:

thin blue bars: rear head - 3, body ~6-8 narrow blue bars
+/- opercle blotch
D 17, A 17
C: 0 branched rays
membrane between jaws:dark
under end top jaw: hook
longitudinal scales 47-59

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

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  • Marine
  • Marine Only
  • Inshore
  • Inshore Only
Water Column Position
  • Bottom
  • Soft bottom (mud/sand/gravel/beach/estuary/mangrove/seagrass)
  • Soft bottom only
  • Mud
  • Reef associated (reef + edges-water column & soft bottom)
FishBase Habitat
  • Demersal
Feeding Group
  • Carnivore
  • Data
  • Planktivore
  • Data
  • Bony fishes
  • Mobile benthic crustacea (shrimps/crabs)
Egg Type
  • Brooded
  • Data
  • Pelagic larva
Global Endemism
  • All species
  • Greater Caribbean endemic
  • West Atlantic Endemic
Regional Endemism
  • Continent
  • Continent only
  • GC endemic
  • All species
  • Resident
Climate Zone
  • Equatorial (0-10N, Costa Rica / Venezuela)
  • Subtropical (23-35N, Florida / Carolinas / Bermuda)
  • Tropical (10-23N, Nicaragua / Cuba)
IUCN Red List
  • Least concern
  • Listed
  • Not listed
Length Max
  • 17.8
Depth Range Min
  • 6
Depth Range Max
  • 265