Order Tetradontiformes
(From the Greek, "tetra-" four,
"dont-" teeth, "formes" bearing.)
This is the group to which puffers, boxfishes
and file fishes belong. All are characterized by the following traits:
- Possession of two pair of large teeth at
the front of the jaws, which are often visible even when the mouth is
closed;
- The gill slits are tiny, often difficult to
see, and lack a covering flap ("operculum");
- A single, posterior dorsal fin;
- A large anal fin;
- Absence of pelvic fins.
Many puffers and boxfishes contain an
extremely virulent poison in the body tissues. In Japan, the preparation of meat
from such puffers is a special skill requiring a license, and the dish served is
called fugu. Despite precautions, some The toxin was first isolated and
analyzed from these fishes, so their name has been given to the toxin:
tetradotoxin. Tetradotoxin, or TTX, is also found in many amphibians, a bird
(New Guinea's pitohui)
and some
other fishes. The evolutionary implication is that TTX is a simple molecule that
has evolved independently in several animal lines. TTX is a powerful neurotoxin
that impairs nervous function, reduces heartbeat, and induces coma (it is also
used in Haiti to make zombies). It may easily cause death in humans.
Among the Tetradontiformes are the a) puffers,
which can rapidly inflate their bodies into a large globe, b) boxfishes and
cowfishes, encased in bony shells, and c) filefishes, which have long erectile
dorsal spines.
