Taxonomy of Finfish (1+2)

Procedure

Based on the exercise ----- separate the group of Tetraodontiformes or using the following character separate the order.

* Pelvic fins absent or strongly reduced (except in Triacanthodidae);

* a small mouth with strong teeth frequently coalesced into a biting plate;

* Maxilla united or fused with premaxilla

* a small gill opening;

* scales usually modified as spines, shields, or plates.

* skin thick or rough, sometimes with prickles, spines or scale plates.

Familiarize the following families using the characters.

TRIACANTHIDAE

* Caudal fin deeply forked;

* caudal peduncle distinctly tapered and depressed,

* wider than deep;

* dorsal-fin spine VI (usually only V visible);rays 20 to 26

* snout never produced into a tube.

* pelvic fins with I large spine and no visible rays

TETRAODONTIDAE

* Jaws modified to form a beak of 4 heavy, powerful teeth, 2 above and 2 below .

* Eyes high on head.

* Gill opening a simple slit in front of pectoral fins.

* Dorsal and anal fins located far posteriorly, containing no spines ,

* Typical scales absent, but many spinules often present on back and/or belly, sometimes on sides.

* pelvic fins absent

BALISTIDAE

* with large scales easily discernible as individual units;

* Scales platelike

* scales above pectoral-fin base in many species enlarged, forming a flexible tympanum.

* teeth strong, 8 in outer series of upper jaw and lower jaw.

* Gill opening a moderately short, vertical to oblique slit in front of pectoral-fin base.

* Two dorsal fins; first dorsal fin with III visible spines, the second spine more than 1/2 length of first spine; first spine capable being locked in an upright position of erection by second spine

* scales usually forming prominent, oblique rows.

MONACANTHIDAE:

* II dorsal-fin spines, only the first of which is long and prominent; body more laterally compressed;

* fewer and less massive teeth in jaws;

* scales shagreen-like, with the individual basal plates small and not readily distinguishable from one another to the unaided eye.

* pelvic fins a bony rudiment fused to posterior end of pelvis, posterior portion movable in some species, or rudiment absent. Pelvis usually capable of vertical movement giving rise to a ventral flap

DIODONTIDAE

* a single tooth-plate in each jaw

* spines in the body

* Capable of inflating the body

* Nasal organ usually in small tentacles located in front of large eyes.

* Gill opening a relatively small, vertical slit immediately before pectoral-fin base. Dorsal and anal fins without spines,

* no pelvic fins .

* Lateral line inconspicuous.

OSTRACIIDAE

* No spiny dorsal fin

* Rigid shell with bony plates

* usually hexagonal in shape

* no isolated bony plates on caudal peduncle.

* caudal fin with 8 branched rays ;

* pelvic fins absent.

* Lateral line inconspicuous.

MOLIDAE

* body short and deep or oblong, prominently compressed;

* Caudal peduncle and typical caudal fin absent .

* Eyes small.

* Mouth terminal, small; teeth united and beak-like in each jaw without a median suture;

* No palatine teeth.

* Gill opening small, pore-like , located in front of pectoral-fin base.

* Dorsal and anal fins of similar shape and spineless,

* Pectoral fins small to moderate sized , located midlaterally,

* Pelvic fins absent;

* Caudal fin replaced by a leathery, rudder-like lobe known as a pseudocaudal fin or clavus (supported mostly by fin-ray elements originally belonging to dorsal and anal fins).

* Skin leathery, with many small scales (small

* Juveniles may also have some larger scattered spiny

Based on the figures given identify some of the similar species available in your region.