Isopoda (slaters)

(from Austin et al. 2022): Isopoda is a diverse group of crustaceans found in marine, freshwater and terrestrial habitats. Along with the Decapoda (prawns, crabs and crayfish), isopods are among the most morphologically diverse of all crustaceans. Although often described as ‘dorsoventrally flattened’, there are many exceptions with some being cylindrical, others laterally compressed and parasitic forms having various shapes. The most familiar isopods are the terrestrial slaters, woodlice and pill bugs. Isopods have sessile, compound eyes (if present), two pairs of antennae, and four sets of jaws. The first antennae are typically chemosensory; the second antennae are typically tactile structures. Isopods have a very reduced carapace and the first segment of the thorax is fused to the head. The remaining 7 free segments (pereonites) of the thorax each normally bear a pair of simple legs (pereopods), all very similar to each other. The pereopods are modified for locomotion and, in predatory species, for grasping prey. The abdomen consists of 5 free segments (pleonites) with the last abdominal segment, to which the uropods are attached, fused with the telson (or tail segment) to form a pleotelson. Each pleonite bears a pair of biramous pleopods, with flat membranous gills which are used for respiration and swimming in aquatic species. Terrestrial and freshwater species vary from white to dark gray, can be patterned and range in length from around 1–25 mm.

All the isopod species Fauna Portal are currently being revised. As such, some diagnoses are incomplete and CO1 information is not yet available.