INVERTEBRATE ZOOLOGY - H. I. Shcherbak - 2008

KINGDOM MULTICELLULAR ANIMALS (METAZOA)

SUBKINGDOM TRUE MULTICELLULAR ANIMALS (EUMETAZOA)

SECTION TRIPLOBLASTIC (TRIPLOBLASTICA) OR BILATERAL (BILATERIA) ANIMALS

SUBSECTION MOLTING ANIMALS (ECDYSOZOA)

PHYLUM ARTHROPODS (ARTHROPODA)

SUBPHYLUM BRANCHIATA OR CRUSTACEANS (CRUSTACEA)

CLASS MAXILLOPODA (MAXILLOPODA)

SUBCLASS BRANCHIURA OR FISH LICE (BRANCHIURA)

A small group (about 130 species) of ectoparasites infesting marine and freshwater Fishes, with three species recorded in Ukraine. The body is flattened dorsoventrally.

The syncephalon is covered by a carapace bearing a pair of compound eyes and one to three naupliar ocelli on the dorsal surface. The antennules and antennae are shortened; the antennules are equipped with a claw-like appendage used for attaching to the fish host. The mandibles are modified into a piercing-sucking proboscis, the first maxillae are transformed into a fixing organ—a sucker—and the second maxillae also function as attachment structures, alongside a pair of maxillipeds. The thoracic appendages are biramous and swimming. The abdomen is rudimentary and fused (Fig. 333).

Fish lice are capable of swimming freely, temporarily leaving their hosts.

A typical representative of branchiurans is the fish louse (Argulus foliaceus), which parasitizes freshwater fishes.

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Fig. 333. Male fish louse Argulus foliaceus (from Dogel):

1 - stylet; 2 - antennule; 3 - Maxilla I; 4 - sucker; 5 - thoracic limbs; 6 - Testis; 7 - digestive gland (Liver); 8 - maxilla II; 9 - antenna, with eye adjacent to it