Balistidae | fishIDER

Osteichthyes Balistidae

Triggerfishes

Characteristic features:

Keys:

All keys adapted from Matsuura, 2001

Balistidae genera

1. Caudal peduncle distinctly depressed, wider than deep Abalistes species
2. Caudal peduncle compressed 2
1. Scales above pectoral-fin base and just behind gill opening much enlarged 3
2. Scales above pectoral-fin base and just behind gill opening not enlarged 8
1. A prominent groove on snout before eye 4
2. No groove on snout before eye 9
1. Teeth red, 2 upper teeth projecting and canine-like Odonus niger
2. Teeth white, not greatly projecting 5
1. Anterior part of cheek largely naked, its posterior part covered with scales smaller than those of body Pseudobalistes species
2. Cheek entirely or except for a fold at the corner of mouth covered with scales 6
1. Upper and lower profiles of head prominently convex, giving the body a distinctive ovoid shape; body uniformly black or deep indigo Melichthys species
2. Upper and lower profiles of head not prominently convex, either concave, straight, or slightly convex; body not uniformly black or deep indigo, but variously coloured with blotches and/or lines 7
1. Longitudinal scale ridges extend only a short distance forward of caudal peduncle Balistoides species
2. Longitudinal scale ridges extend to at least middle of body Sufflamen species
1. Three to 6 naked longitudinal, somewhat oblique grooves on cheek; mouth slightly, but distinctly supraterminal Xanthichthys species
2. Cheek evenly scaly, without naked grooves; mouth terminal Canthidermis maculata
1. Third dorsal-fin spine developed, extending above dorsal edge of body; caudal peduncle with 2 longitudinal rows of large anteriorly projecting spines Balistapus undulatus
2. Third dorsal-fin spine minute, extending slightly above dorsal edge of body; caudal peduncle with 3–5 longitudinal rows of small spines Rhinecanthus species

Abalistes species

1. 3 or 4 longitudinal grooves on cheek; upper and lower caudal fin lobes filamentous (except on small juveniles) Abalistes filamentosus
2. No longitudinal grooves on cheek; caudal fin without filamentous lobes (in adults and sub adults) Abalistes stellatus

Balistoides species

1. Cheek entirely covered with scales; ventral part of body with large rounded white spots Balistoides conspicillum
2. A naked longitudinal fold behind corner of mouth; ventral part of body without white spots Balistoides viridescens

Melichthys species

1. Soft dorsal and anal fins pale with prominent black margins; caudal fin pale pink with a white base Melichthys vidua
2. Soft dorsal and anal fins dark to black with a longitudinal pale line at base; caudal fin black, sometimes with a narrow white margin 2
1. Caudal fin rounded; caudal fin black without white margin; scale rows from corner of mouth to lower end of gill opening 27–31 Melichthys indicus
2. Caudal fin emarginate to lunate; caudal fin sometimes with a white margin; scale rows from corner of mouth to lower end of gill opening 20–25 Melichthys niger

Pseudobalistes species

1. Five or 6 longitudinal scale ridges on caudal peduncle ; soft dorsal and anal fins rounded, not elevated anteriorly in adults Pseudobalistes flavimarginatus
2. No scale ridges on caudal peduncle; soft dorsal and anal fins elevated anteriorly in adults Pseudobalistes fuscus

Rhinecanthus species

1. Distinctive black triangular mark on posterior body/caudal peduncle Rhinecanthus rectangulus
2. No distinctive black triangular mark on posterior body/caudal peduncle 2
1. Uppermost row of small spines on posterior body much shorter than lower 2 rows; a large elliptical black blotch on lower side of body Rhinecanthus verrucosus
2. Lowermost row of small spines on posterior body much shorter than upper 2 rows; no large elliptical black blotch on lower side of body Rhinecanthus rectangulus

Sufflamen species

1. Two vertical curved dark bands next to gill opening, the anterior band through eye curving downward to lower part of pectoral-fin base, the posterior band from upper part of pectoral-fin base towards middle of, but not reaching to, spinous dorsal fin Sufflamen bursa
2. No vertical dark black bands next to gill opening 2
1. Caudal fin with a broad white posterior margin; pale vertical band under eye (may fade after death) Sufflamen chrysopterum
2. Caudal fin uniformly dark; a narrow pale line often present under chin Sufflamen fraenatum

Xanthichthys species

1. Cheek with 3 slightly oblique dark brown grooves; upper half of body with longitudinal dark brown lines Xanthichthys lineopunctatus
2. Cheek with 5 or 6 slightly oblique grooves; body without longitudinal dark brown lines 2
1. A thin, irregular longitudinal pale, sometimes blue line on sides from pectoral-fin base to upper part of caudal peduncle vertical orange stripe behind eye Xanthichthys caeruleolineatus
2. No longitudinal blue line on body; chin area blue Xanthichthys auromarginatus

Similar families:

Monacanthidae
Leatherjackets

Monacanthidae differs in having 2 dorsal-fin spines, with only the first long and prominent (vs. 3 dorsal-fin spines, all long and prominent); body very compressed (vs. only slightly compressed); scales minute (vs. large) and smaller and fewer teeth in jaws (vs. larger and more numerous).

to Monacanthidae

Species: