Australian Isopoda: Families

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

Holidoteidae Wägele, 1989

Holidoteinae Wägele, 1989: 137.

Holidoteidae. -Poore, 2001b: 223.

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; in lateral view straight, more or less flattened or semicylindrical, or flexed between pereonites 4 and 5. Body surface smooth or slightly sculptured, or variously spinose or rugose.

Head. Head not capable of lateral rotation (laterally encompassed, abutting or fused to pereonite 1); fused to pereonite 1. Eyes well developed, or reduced or lost (rare). Antenna 1 inserting on head anteriorly and/or dorsally to antenna 2, minute or well developed; not as follows: reduced to 2 articles with second article expanded and scalloped. Antenna 2 well developed; flagellum of 2-3 articles plus distal claw. Mouthparts not forming suctorial cone or proboscis; with pereopod 1 visible in lateral view (may be hidden by expanded tergites). Mandible not projecting anteriorly and together forceps-like; palp absent.

Pereon. Pereonite 4 of similar length to pereonite 3. Pereonites 6-7 pereonite 7 distinct dorsally, free. Coxae extending ventrally and laterally to overhang the coxa-basis articulation of the pereopods, or not extending ventrally and laterally to overhang the coxa-basis articulation of the pereopods; 2-7 obsolete, bases of pereopods exposed, or 2-7 obsolete and with expanded marginal tergites (females only). Oostegites 1-4 functional, 5 absent; 1-4 supported by mesial coxal lobes. Pereopods 6-7 pairs readily apparent; 1-3 or 1-7 not prehensile; 1 a gnathopod, 2-4 elongated, differentiated from ambulatory 5-7; without dense fur of fine setae in males. Pereopod 1 dactylus evenly curved along anterior margin, evenly tapering. Pereopods 2-4 with scattered and uneven long setae along posterior margins; 2-4 dactylus short, unguis longer and setiform. Pereopod 4 similar to pereopod 3. Pereopods 5-7 without flattened setose articles andor dactyls modified or absent. Penes fused as a single penial plate; penial plate apically bifid and splayed.

Pleon / Pleotelson. Pleonites and pleotelson with pleonites 1-5 and pleotelson fused, or pleonites 2-5 and pleotelson fused, pleonite 1 articulating (weakly). Pleopods 5 pairs present. Pleopod 1 peduncle longer than peduncle on pleopods 2-5; marginal setae on rami longer than, or equal to, length of rami; exopod of males thickened and with groove on posterior face, with groove on posterior face ending on distolateral lobed tip, separated from most of lateral margin by notch, lateral margin terminating at subdistal excavation, with overlapping rows of simple and plumose setae. Pleopod 2 of males not consisting of an enlarged peduncle with a geniculate endopod and a small muscular exopod; appendix masculina about as long as endopod, basally less than half width of endopod. Pleotelson without dorsolateral ridges ending in mediodorsal posterior spine. Uropods positioned proximally on pleotelson; folded ventrally below pleotelson, forming operculum enclosing pleopodal chamber. 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, very short, bearing a single prominent robust seta (endopod also with robust apical seta).

Distribution and generic composition. Confined to southern Africa (Poore, 2001b), See Kensley et al. (1996) but note Poore (2001b) considers the family to be comprised of the following genera with numbers of species in parentheses: Austroarcturus Kensley, 1975 (6, contintental shelf); Holidotea Barnard, 1920 (1, continental shelf); Neoarcturus Barnard, 1914 (9, continental shelf and slope) (16 species in all). Poore (2001b) indicates that a revision of the family including a resolution of complex nomenclatural issues resulting from use of the nomen nudum Microarcturus is in preparation for the Annals of the South African Museum.

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