Terrestrial isopods (Crustacea, Oniscidea) from Hawaiian caves

Nineteen species of terrestrial isopods are recorded from 56 caves, mainly lava tubes, in the Hawaiian Islands. One genus (Aulaconiscus) and four species (Aulaconiscus caecus, Hawaiioscia microphthalma, H. rotundata and H. paeninsulae) are described as new. Most species are trogloxenous, introduced from the Mediterranean and Europe or widespread in the tropics. Four species in the genus Hawaiioscia (Philosciidae) from caves on the islands of Kauai, Oahu, Molokai and Maui, are considered to be truly troglobitic. A further species of Philosciidae, Littorophiloscia sp. from lava tubes on Hawaii Island, closely related to the endemic littoral halophilic L. hawaiiensis, shows some troglomorphic regressed character (depigmentation and eye reduction) and might belong to a separate species. The composition and origin of the cave-dwelling Hawaiian Oniscidea is discussed.