Tetraodontiformes - AccessScience from McGraw-Hill Education http://www.accessscience.com/content/tetraodontiformes/686800

Article by:

Boschung, Herbert Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama.

Publication year: 2014

DOI: http://dx.doi.org/10.1036/1097-8542.686800 (http://dx.doi.org/10.1036/1097-8542.686800)

Content

Suborder Triacanthodoidei

Suborder Balistoidei

Suborder Tetraodontoidei

Bibliography

Additional Readings

An order of the class Actinopterygii, also known as the Plectognathi. This most highly derived order of actinopterygian fishes

is noted for its reduction in skeletal elements. Lost are the parietal, nasal, and infraorbital bones of the skull. Usually there are

no pleural ribs; vertebrae are as few as 16 and no more than 30; and the maxillae are united with the premaxillae. The gill

opening is a short vertical slit in front of the pectoral fin. Scales are usually modified to form spines, shields, or plates; a lateral

line may be present or absent; and a swim bladder is present, except in the family Molidae. The 357 extant species are in

three suborders, nine families (see illustration), and about 101 genera. See also: Actinopterygii (/content/actinopterygii

/009100); Osteichthyes (/content/osteichthyes/478500); Swim bladder (/content/swim-bladder/672500)

Representations of eight families (Triodontidae is not pictured) of the Tetraodontiformes. (Courtesy of J. S. Nelson, Fishes of the World, 4th ed., Wiley, 2006)

Suborder Triacanthodoidei

The single family, Triacanthodidae (spikefishes), is characterized by a deep and moderately compressed body, which is

covered with a thick skin and tiny scales; each scale bears spicules, resulting in the skin having a shagreen-like appearance

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(that is, rough-looking skin covered with small close-set tubercles); the caudal fin is rounded to truncate; there are usually six

dorsal fin spines and 12–18 dorsal fin rays; 11–16 anal rays; and a caudal fin with 12 principal rays. Each pelvic fin consists of

one stout spine and one or two soft rays; the pelvic spines can be locked into place. There are 20 vertebrae. Some species

have an extremely long snout; for example, in Halinochirurgus akacki the snout is about equal in length to the entire body

posterior to the eye. Species of spikefishes range in total length from about 5.3 to 26 cm (2 to 10 in.). They are benthic in

deep waters of the tropical and subtropical Atlantic and Indo-Pacific oceans.

Suborder Balistoidei

Balistoidei is also known as Sclerodermi. In the following four families, the frontal bones extend far anterior to the articulation

between the lateral ethmoid and ethmoid bones.

T r i a c a n t h i d a e ( t r i p l e s p i n e s )

This family, formerly placed in the suborder Triacanthodoidei, is superficially similar to the Triacanthodidae but can be

distinguished from them by their deeply forked caudal fin vs. round or truncate caudal fin; dorsal fin rays 19–26 vs. 12–18;

anal fin rays 13–22 vs. 11–16; and maximum length about 28 cm (11 in.). The family comprises four genera and seven

species, limited to shallow waters of the Indo-Pacific Ocean.

B a l i s t i d a e ( t r i g g e r f i s h e s )

This family is characterized by a deep and moderately compressed body covered with a very thick, tough skin bearing

rectilinear scale plates. The scales above the pectoral fin base are usually enlarged and slightly separated, forming a flexible

tympanum. There is a small and usually terminal mouth, and a row of eight strong outer teeth in both the upper and lower

jaws. There are three dorsal fin spines, the first of which can be locked in an upright position by the second; pelvic fins and

spines are rudimentary or absent. There are 18 vertebrae. Eleven genera and about 40 species occur in the Atlantic, Indian,

and Pacific oceans, either pelagic open water or benthic around rocky or coral reefs.

M o n a c a n t h i d a e ( f i l e f i s h e s )

Filefishes are characterized by a deep and compressed body covered with tiny scales, which are prickly or velvety to touch.

There are usually two dorsal spines; the second is usually much smaller or absent. The upper jaw usually has three teeth in

the outer series and two in the inner on each premaxillary, developed for nibbling. There are 19–31 vertebrae. Most species

feed on a wide variety of benthic invertebrates, but some specialize on corals or zooplankton. Filefishes lay demersal (living

at or near the bottom of the sea) eggs in a site prepared and guarded by the male or both parents. Some of the subtropical

species release eggs in open water. Filefishes are generally small, and some reach a length of only 3.6 cm (1.4 in.); however,

the largest member of the family, Aluterus scriptus, attains a length of 110 cm (43.3 in.). The family comprises approximately

102 marine species, which occur in the Atlantic, Indian, and Pacific oceans; about half of them occur in Australian waters.

O s t r a c i i d a e ( b o x f i s h e s , c o w f i s h e s , t r u n k f i s h e s )

The Ostraciidae are characterized by the entire body (except the caudal peduncle) being encased in an immovable bony

carapace consisting of fused hexagonal plates; no pelvic skeleton; no spinous dorsal; dorsal and anal fins each with 9–13

rays; nonprotrusible upper jaw; usually 18 vertebrae; and maximum length of 11–55 cm (4.3–21.6 in.), depending on the

species. Some species secrete ostracitoxin, poisonous to other fishes and to some extent other ostracians. The habitat is

usually seagrass and coral, where they feed on worms and other small sessile invertebrates. Some species use strong jets of

water from the mouth to dislodge prey from the substrate (an interesting adaptation for a fish with a small nonprotrusible

mouth and few moving body parts). Movement is slow and accomplished primarily by a sculling motion of the slender caudal

peduncle. The family comprises two subfamilies, Aracaninae (a ventral ridge more or less developed and 11 principal caudal

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Tetraodontiformes - AccessScience from McGraw-Hill Education http://www.accessscience.com/content/tetraodontiformes/686800

Tetraodontiformes - AccessScience from McGraw-Hill Education http://www.accessscience.com/content/tetraodontiformes/686800

rays) and Ostraciinae (no ventral ridge and 10 principal caudal rays). Some authors recognize the subfamilies as separate

families. There are about 33 species, some with beautiful bright colors, in the tropical and temperate waters of the Atlantic,

Indian, and Pacific oceans.

Suborder Tetraodontoidei

These fishes do not have true teeth; instead the upper and lower jaws have sharp cutting edges that form a beak similar to

that seen in the parrotfishes; there may be two, three, or four such “teeth,” depending on the presence or absence of sutures;

and the posttemporal bones are absent, as are usually the urohyal, pelvis, and pelvic fins.

T r i o d o n t i d a e ( t h r e e t o o t h p u f f e r s )

The single species of this family has three fused teeth (a median suture in the upper jaw, none in the lower); pelvis present;

dorsal and anal fins each usually with 11 rays; caudal fin with 12 principal rays and deeply forked; ribs and epipleurals

present; large belly flap; and maximum total length about 54 cm (21 in.). It is a reef associate of the Indo-West Pacific to

depths of 50–300 m (164–984 ft).

Te t r a o d o n t i d a e ( p u f f e r s )

Members of this family are identified by a robust body, naked or with short prickles on sides and belly; some species with

small fleshy appendages (lappets) on the sides; jaw teeth fused but separated by a median suture in each jaw, giving rise to

four fused teeth; dorsal and anal fins far posteriorly, each consisting of 7–18 dorsal soft rays; ribs and epipleurals lacking;

caudal fin with 10 principal rays and moderately forked to rounded; and maximum size of 3.5–120 cm (1.4–47.2 in.) total

length, depending on the species. Puffers are capable of greatly inflating themselves with water or air when agitated. Some

puffers contain the potential lethal poison tetrodotoxin, especially in the viscera and in the gonads of some during spawning

season. They are chiefly marine, usually inhabiting shallow inshore waters of tropical and temperate waters of the Atlantic,

Indian, and Pacific oceans; however, many species inhabit brackish water, but only 12 of about 162 species of puffers are

limited to freshwater. See also: Toxin (/content/toxin/702800)

D i o d o n t i d a e ( p o r c u p i n e f i s h e s , b u r r f i s h e s )

Members of this family are also capable of inflating the body with water or air, but differ from the puffers in having strong

sharp spines and two fused teeth in the jaws, which form a powerful parrotlike beak. The spines of burrfishes are permanently

erect, whereas those of the porcupinefishes are erect when the body is inflated. The family is further identified by opposite

premaxillaries and dentaries being fused at midline. Maximum size is 27–91 cm (10.6–35.8 in.) total length. The family is

represented by 19 species in tropical and temperate waters of the Atlantic, Indian, and Pacific oceans. Adults occupy inshore

waters, whereas eggs and young are pelagic. Adults feed primarily on hard-shelled invertebrates crushed by the beak.

M o l i d a e ( m o l a s )

Molas are characterized by a moderately compressed body and thick leathery skin; tiny mouth and jaws with two fused

beaklike teeth; no caudal peduncle or true caudal fin; posterior end of body reduced to a leathery flap (clavus) or a

pseudocaudal fin formed by posteriorly migrated dorsal and anal fin rays; no pelvic fins; no lateral line; no swim bladder; and

16–18 vertebrae. Molas are strong swimmers, using the sculling motion of the powerful dorsal and anal fins. The ocean

sunfish (Mola mola) is probably the most fecund fish with an estimated 300 million eggs. The young differ markedly from

adults in having a spiny globular body. Adults feed largely on jellyfishes and other soft-bodied pelagic invertebrates and grow

to 337 cm (11 ft) in total length and 1500 kg (3300 lb) in weight. Distribution is worldwide in tropical to temperate seas.

Herbert Boschung

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Bibliography

T. Abe, Balistidae, in W. Fischer and P. J. P. Whitehead (eds.), FAO Species Identification Sheets for Fishery Purposes:

Eastern Indian Ocean (Fishing Area 57) and Western Central Pacific (Fishing Area 71), vol. 1, FAO, Rome, 1974

K. Matsuura, Balistidae: Triggerfishes, pp. 3911–3928 in K. E. Carpenter and V. Niem (eds.), FAO Species Identification

Guide for Fishery Purposes: The Living Marine Resources of the Western Central Pacific, vol. 6, FAO, Rome, 2001

J. S. Nelson, Fishes of the World, 4th ed., Wiley, New York, 2006

C. R. Robins and G. C. Ray, A Field Guide to Atlantic Coast Fishes of North America, Houghton Mifflin, Boston, 1986

R. Santini and C. Tyler, A phylogeny of the families of fossil and extant tetraodontiform fishes (Acanthomorpha,

Tetraodontiformes), Upper Cretaceous to Recent, Zool. J. Linn. Soc., 139:565–617, 2003 DOI:

10.1111/j.1096-3642.2003.00088.x (http://dx.doi.org/10.1111/j.1096-3642.2003.00088.x)

M. M. Smith and P. C. Heemstra, Balistidae, pp. 876–882 in M. M. Smith and P. C. Heemstra (eds.), Smith's Sea Fishes,

Springer-Verlag, Berlin, 1986

E. Tortonese, Molidae, pp. 1348–1350 in P. J. P. Whitehead et al. (eds.), Fishes of the North-eastern Atlantic and the

Mediterranean, vol. 3, UNESCO, Paris, 1986

J. C. Tyler, Balistidae, Diodontidae, Monacanthidae, Ostraciidae, in W. Fischer (ed.), FAO Species Identification Sheets for

Fishery Purposes: West Atlantic (Fishing Area 31), vols. 1–5, FAO, Rome, 1978

J. C. Tyler, Osteology, Phylogeny, and Higher Classification of the Fishes of the Order Plectognathi (Tetraodonti-formes),

NOAA Tech. Rep. NMFS Circ. 434, October 1980

Additional Readings

G. Helfman et al., The Diversity of Fishes: Biology, Evolution, and Ecology, 2d ed., Wiley-Blackwell, Chichester, West Sussex,

UK, 2009

P. Konstantinidis and M. P. Harris, Same but different: Ontogeny and evolution of the musculus adductor mandibulae in the

Tetraodontiformes, J. Exp. Zool. B Mol. Dev. Evol., 316B(1):10–20, 2011 DOI: 10.1002/jez.b.21375 (http://dx.doi.org/10.1002

/jez.b.21375)

K. Venkataraman, C. Raghunathan, and C. Sivaperuman (eds.), Ecology of Faunal Communities on the Andaman and

Nicobar Islands, Springer-Verlag, Berlin, Germany, 2012

Y. Yamanaka et al., Monophyletic origin of the dorsally arched lateral line in Teleostei: Evidence from nerve innervation

patterns, Ichthyol. Res., 57(1):49–61, 2010 DOI: 10.1007/s10228-009-0122-1 (http://dx.doi.org/10.1007/s10228-009-0122-1)

Animal Diversity Web (http://animaldiversity.ummz.umich.edu/site/accounts/classification/Tetraodontiformes.html)

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