Isopoda
Guides
Caecidotea kenki
Caecidotea kenki is a spring-dwelling asellid isopod found in the eastern United States. Originally described as Asellus kenki by Bowman in 1967, it is one of only three asellid species in Maryland habitually associated with springs rather than subterranean caves. It is distinguished from the six obligate cave-dwelling Caecidotea species in the region by its surface water habitat preference.
Cirolanidae
Cirolanidae is a family of aquatic isopod crustaceans established by Dana in 1852. The family encompasses approximately 70 genera and over 500 species, ranging from small interstitial forms to the supergiant deep-sea isopods of the genus Bathynomus that can exceed 30 cm in length. Members occupy diverse aquatic habitats including marine coastal waters, deep-sea environments, freshwater systems, and subterranean groundwater. The family is characterized by dorsoventrally flattened bodies and includes both free-living and troglobitic species.
Elumoides
Elumoides is a genus of terrestrial isopods in the family Eubelidae, established by Taiti and Ferrara in 1983. These woodlice belong to the suborder Oniscidea, representing a group of fully terrestrial crustaceans. The genus is part of the diverse isopod fauna found in tropical and subtropical regions.
Peracarida
Amphipods, Isopods, and Allies
Peracarida is a superorder of malacostracan crustaceans comprising approximately 12,000 species across 13 orders. The group is defined by the presence of a marsupium (brood pouch) formed by oostegites—flattened plates on the basalmost leg segments of females. Members occupy marine, freshwater, and terrestrial habitats, ranging from minute interstitial forms to the giant isopod Bathynomus giganteus (76 cm) and giant amphipod Alicella gigantea (34 cm). The earliest known peracaridian, Oxyuropoda ligioides, dates to the Late Devonian (~360 mya).
Tylidae
Calloused Beach Pillbugs and Heller's Isopod
Tylidae is a family of terrestrial isopods (woodlice) comprising approximately 27 species, with all but one species placed in the genus Tylos; the sole exception is Helleria brevicornis. Together with Ligiidae, Tylidae represents an early-diverging lineage among woodlouse families. Members are primarily associated with coastal sandy beach habitats in the supralittoral zone.