An overview ofthe present knowledgeofthe family Stenasellidae (Asellota; Aselloidea) is presented, focusing on the success of recent investigations of the underground waters ofOman (S.E. Arabian Peninsula). We take up the discovery offour new species ofthe genus Stenasellus: small species adapted to interstitial biotopes and larger ones typical of karstic aquifers. These species cohabit in ecotones between interstitial and karstic water systems. The putative presence ofstenasellids in hypogeanwaters ofYemen and South Iran is suggested. The taxonomic status of the genus Stenasellus auct. needs to be reconsidered in the future. A scenario to explain the origin and the presence of these isopods in continental underground waters is advanced.

An overview ofthe present knowledgeofthe family Stenasellidae (Asellota; Aselloidea) is presented, focusing on the success of recent investigations of the underground waters ofOman (S.E. Arabian Peninsula). We take up the discovery offour new species ofthe genus Stenasellus: small species adapted...