Australian Isopoda: Families

S.J. Keable, G.C.B. Poore & G.D.F. Wilson


Ligiidae Brandt & Ratzeburg, 1831

Ligiidae Brandt & Ratzeburg, 1831: xxx. -Roman & Dalens, 1999: 297.

Description. Body. Body shape without loss or gross modification of appendages on one side of the body; in dorsal view without peduncular articles of antenna 1 or 2 contiguous with coxal margins.

Head. Head not capable of lateral rotation (laterally encompassed, abutting or fused to pereonite 1). Antenna 1 inserting on head directly between and in same horizontal plane as antenna 2, usually minute; not as follows: reduced to 2 articles with second article expanded and scalloped. Antenna 2 well developed; flagellum with more than 10 articles. Mouthparts not forming suctorial cone or proboscis. Mandible not projecting anteriorly and together forceps-like; palp absent.

Pereon. Pereonites 6-7 pereonite 7 distinct dorsally, free. Coxae extending ventrally and laterally to overhang the coxa-basis articulation of the pereopods. Coxae 2-7 not clearly separated from pereonites 2-7 by suture line. Pereopods 6-7 pairs readily apparent; 1-3 or 1-7 not prehensile. Pereopods 5-7 without flattened setose articles andor dactyls modified or absent. Penes paired, fused only at base.

Pleon / Pleotelson. Pleonites and pleotelson not arranged as follows: pleonites 1-5 fused but with conspicuous lateral sutures, pleotelson fused to pleonites 1-5; pleonites 1-5 fused but with conspicuous lateral sutures, pleotelson not fused to pleonites 1-5; pleonites 1-5 fused without conspicuous sutures, pleotelson not fused to pleonites 1-5; pleonites 2-5 fused but with partial (usually lateral) sutures, pleotelson wholly or partly fused with pleonites 2-5; pleonites 3-5 fused without lateral sutures, pleotelson fused with pleonites 3-5, pleonites 1 and 2 free but may be only small rings or cuticular bars visible ventrally. Pleonite 5 subequal to or shorter than any of pleonites 1-4. Pleopods 5 pairs present. Pleopod 2 of males not consisting of an enlarged peduncle with a geniculate endopod and a small muscular exopod. Pleotelson posterior margin acute lateral processes present. Uropods positioned distally on pleotelson; distinct from pleopods, not forming operculum over pleopodal chamber (although may be folded ventrally below pleotelson); not folded ventrally to form operculum over anus, usually projecting beyond pleotelson, attaching along posterior margin of pleotelson. Peduncle not forming an elongate clavate article with rami reduced or absent. Endopod not claw-like (acute and recurved) andor posteroventral in position. Exopod not folded dorsally over pleotelson.

Distribution and generic composition. See Kensley et al. (1996).




Cite this publication as: 'S.J. Keable, G.C.B. Poore & G.D.F. Wilson (2002 onwards). 'Australian Isopoda: Families. Version: 2 October 2002. http://crustacea.net'.