The isopods are a remarkably diverse group of per-acarids that have colonised almost all habitats, from terrestrial leaf litter to abyssal depths. Isopods are characterised by fixed, immovable eyes, no carapace, seven pairs of thoracic legs, five pairs of pleopods, and a pleotelson (formed by fusion of the last two body segments). Most isopods have the familiar, flattened, oval body shape. The largest isopod, the deep-sea Bathynomus giganteus, reaches 35 cm in length, but on the GBR, most species are less than 10 mm long. Some
200 species of isopod are known from the GBR, and most obvious are the mostly free living flabelliferans, particularly species of the families Cirolanidae (Fig. 23.1 G) and Sphaeromatidae (Fig. 23.1H). Cirolanids are efficient scavengers, emerging from the substratum to swim rapidly towards a food source such as a dead or maimed fish. They can also be voracious predators, sometimes biting humans. Sphaeromatids are perhaps less conspicuous than the cirolanids, but often have a highly sculptured pleotelson and trailing uro-pods. Some isopods vary markedly from the 'typical' form. These include the slender valviferans and anthu-rideans, and most notably the endoparasitic bopyroids that infect decapods. Bopyroids have lost many of the features of free living isopods, and being internal parasites, are seldom seen. A rounded bulge on the surface of the carapace of the decapod host is the only external clue that a bopryroid lies beneath. Other parasitic iso-pods such as the cymothoids (Fig. 23.1!) infect the skin, mouth, and gills, of fish, to which they cling with sharp, hooked 'feet'.
Was this article helpful?
Do You Want To Learn More About Green Living That Can Save You Money? Discover How To Create A Worm Farm From Scratch! Recycling has caught on with a more people as the years go by. Well, now theres another way to recycle that may seem unconventional at first, but it can save you money down the road.