A new species of Aega Leach, 1816 (Isopoda: Aegidae), a micro-predator of elasmobranchs from eastern Tasmania, Australia

Aega serricauda sp. nov., from southeastern Australian waters, belongs to a group of species within Aega that is characterised by a strongly flattened antennula peduncle, a prominent seta opposing the dactylus on pereopods 2 or 2 and 3, and moderately to strongly serrate margins to the pleotelson and uropods. In addition, species in this group have elongate bodies with subparallel margins. Aega serricauda is characterized by the pleotelson being nearly as long (0.97 ratio) as wide, a clearly angled posterior margin (that part that is serrated, with slender and robust setae) that forms an angle of 95° at the apex, lateral margins (the lateral part free of setae) comprising 40% or pleotelson length, and uropodal rami extending to or slightly beyond the pleotelson posterior margin. A. serricauda sp. nov. has been recorded in waters off eastern Tasmania and was collected from the surface of three species of elasmobranch: Galeorhinus galeus (school shark), Squalus acanthias (spiny dogfish) and Dipterus cerva (white spotted skate).