ABSTRACT
The Order Amphipoda (see Crustacea: Amphipoda) is characterized as being laterally compressed, lacking a carapace, and being generally an aquatic group consisting of more than 6700 species placed in three suborders: Caprellidea, Gammaridea, and Hyperiidea. Stygobitic amphipods are known only from the large Suborder Gammaridea (>5700 species) and the approximately 750 troglomorphic species are assigned to about 160 genera. Although there are more than 30 families, the Bogidiellidae, Crangonyctidae (Figure 4c), Hadziidae, and Niphargidae demonstrate the greatest biodiversity. They are found virtually in all parts of the globe with appropriate habitats, but Central and Southern Europe, the Mediterranean region, eastern and southern North America, and the Caribbean house the largest taxonomic diversity of stygobitic amphipods.
