Two new genera of marine isopod crustaceans (Flabellifera : Sphaeromatidae) from southern Australia, with a reappraisal of the Sphaeromatidae

Abstract

Two new genera, Juletta and Margueritta, and the species Juletta mirandae, sp. nov., J. fika, sp. nov., and Margueritta sylviae, sp. nov. are described. The genera are both characterised by having a unicuspidate mandible incisor, both mandibles lacking a lacinia mobilis, medial lobe of maxillule with three spines, pleopods 1 operculate, pleonite 1 free and pleonites 3–6 indistinguishably fused to telson.

Margueritta can readily be distinguished from Juletta by the presence of a pleotelsonic foramen and the lack of a proximal lobe on the palm of pereopods 2 and 3. Both genera are recorded from the intertidal or shallow subtidal zones (25 m), and are recorded from eastern Tasmania, Victoria, South Australia (Juletta) and southern Western Australia (Juletta and Margueritta).

The distinctive mouthpart morphology of these genera led to a reappraisal of the mouthpart morphology of the constituent subfamilies of the Sphaeromatidae. It is principally mouthpart characters that are used to distinguish the newly redefined and elevated families Ancinidae Dana, 1852, and Tecticipitidae Iverson, 1982 from the Sphaerornatidae. The Sphaeromatidae are similarly rediagnosed with a more restrictive diagnosis. A synoptic list and key to the families of Flabellifera are given.