Animal classes
Freshwater isopods (Isopoda Aquatica)
Even 34 taxa (species and subspecies) of freshwater crustaceans was found in Croatia, together with several new undescribed species. Of this as much as 23 are cave species, 5 species live in underground interstitial habitats, 4 in the brackish waters in the coastal area and only 2 species are from rivers and lakes. Cave species are due to the lack of light lost pigment completely and sense of sight. Most cave species feeds on dead organic matter (detritus), but some are even predators (Dalmatian giant pill-bug; Sphaeromides virei mediodalmatina). These species are often of very limited distribution, and therefore very vulnerable. For instance, Dalmatian blind water-louse (Proasellus anophthalmus dalmatinus) is spread in a very narrow area in the southern Dalmatia and Herzegovina, and found in a few caves. And Pretner's spined cave pill-bug (Monolistra pretneri spinulosa) is spread in several caves along the river Zrmanja around Žegar and within the river Krka around Krka National Park, and the distribution includes the only island findings of genus Monolistra in Croatia on the island of Cres.
