There are about 5000 species of marine isopods, but less than 20 free-living ones are common in intertidal and supratidal regions of the west coast of North America.   Owing to their generally nocturnal habits and preference for under-rock and under-seaweed habitats, many species are not obvious to the casual observer.  An equal or greater number of species are parasitic or wood-boring (with a few exceptions the parasitic species are not included in the ODYSSEY).  Isopods are of special interest because terrestrial representatives frequent our gardens (woodlice and sowbugs), and transitional evolutionary forms exist from the more advanced terrestrial species to prototypal land colonisers living on supratidal shores. 

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ANIMATION of snail meeting ISOPOD
© 2010 Thomas Carefoot

To learn about west-coast ISOPODS: select a topic from the isopod menu at the top of the page

OR: play the ANIMATION of the snail meeting the ISOPOD

OR, if you want to see other animations: follow the snail on its ODYSSEY by CLICKING on any X-marked invertebrate on the map

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Isopods along with shrimps, crabs, barnacles, and amphipods (in the order of occurrence in the ODYSSEY) are classified in the Subphylum Crustacea of the Phylum Arthropoda:

Phylum Arthropoda (lit. “jointed legs” G.)

Subphylum Crustacea (lit. “crust or rind ” L.), referring to the hard calcified exoskeleton

Class Malacostraca includes “advanced” crustaceans

Order Isopoda (lit. “equal feet” G.), referring to 7 pairs of undifferentiated locomotory appendages; includes about a dozen recognised suborders, of which 4 are represented in the ODYSSEY

Suborder Flabellifera includes Limnoria, Exocirolana, Gnorosphaeroma

Suborder Valvifera includes Idotea

Suborder Epicaridea includes parasitic bopyrids

Suborder Oniscidea includes the semiterrestrial Ligia and many terrestrial species
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