Cymothoidae

Cymothoidae is a family of isopod crustaceans commonly known as tongue-eating lice. They are obligate parasites of fish, with most species found in marine environments. They are distinguished by their flattened bodies, large, powerful mandibles, and the ability to modify their morphology to suit their parasitic lifestyle.

Nerocila fluviatilis

Nerocila monodi

Parasitic Isopod, Tongue-eating Louse, Fish Tongue Biter – Cymothoa exigua

Cymothoa pulchrum

Anilocra longicauda

Parasitic Isopod – Anilocra physodes

Striped Fish Louse – Anilocra capensis

Anilocra haemuli

Blackbar Soldierfish Isopod – Anilocra myripristis

Anilocra acuta

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Common Names

While tongue-eating lice is the most common name for members of this family, they are also known as fish lice or simply cymothoids.

Characteristics

Cymothoidae exhibit a range of adaptations for their parasitic lifestyle. They are typically dorsoventrally flattened, with a body divided into three segments: a cephalon (head), a pereon (thorax), and a pleon (abdomen). The cephalon bears a pair of large, powerful mandibles used to feed on their host's flesh, as well as a pair of antennae and eyes.

The pereon is composed of seven segments, each bearing a pair of legs. The pleon contains six segments and a pair of uropods, which are tail-like appendages. Some species of Cymothoidae, like Cymothoa exigua, are known for their unique ability to replace their host's tongue. The parasite attaches to the base of the tongue and feeds on its blood, eventually causing the tongue to atrophy. The parasite then replaces the tongue, functioning as a surrogate organ for feeding.

Environments

Most species of Cymothoidae are found in marine environments, typically attaching to the gills, mouth, or skin of their host fish. They can be found in various geographical regions, including the Atlantic, Pacific, and Indian Oceans.

References

For further information on Cymothoidae, consult the following resources: