A guide to the identification of the terrestrial Isopoda of Maryland, U.S.A. (Crustacea)

Abstract. The terrestrial isopod fauna of Maryland is inferred using the taxonomic literature, internet-based citizen science projects, and original collecting. Twenty-two species are either known or are likely to occur in the state. This includes 17 mostly-European adventive species that comprise the vast majority of records. Of the five expected native species, three occur in or near marine or estuarine littoral habitats and each has yet to be recorded or recorded from only a single locality. This situation likely reflects the long history of systematic work on the European fauna and the availability of keys for the identification of these taxa, which contrasts with the limited taxonomic work on native species. A taxonomic key, illustrations, and brief descriptions of species known or expected to occur in Maryland are provided.