Styloptocumoides australiensis, Petrescu, 2006

Petrescu, Iorgu, 2006, Nannastacidae (Crustacea: Cumacea) from eastern Bass Strait, the south-eastern Australian slope, and Antarctica in the collections of Museum Victoria, Memoirs of Museum Victoria 63 (2), pp. 129-173 : 169-170

Styloptocumoides australiensis sp. nov.

Figure 64

Material examined. Holotype female, NSW, off Nowra, 34°51.90'S, 151°12.60'E, 770 m, crinoid dominated, WHOI epibenthic sled, G.C.B. Poore and C.C. Lu, RV Franklin, 15 Jul 1986 (stn SLOPE 6 ), NMV J53060.

Diagnosis. Pseudorostrum 0.38 of carapace length, ocular lobe eyeless, reaching its tip, few setae on carapace, no spines on entire body, smooth lower margin of carapace. Basal article of peduncle of antenna 1 shorter than rest of articles combined, short main flagellum. Maxilliped 3 with a strong tooth on outer margin of merus. Pereopod 1 with carpus 2nd longest article, dactylus with long curved robust terminal seta. Pereopod 2 with carpus little longer than merus, with 2 robust short setae on its distal inner corner, short dactylus. Pereopods 3–5 progressively shorter, with dactylus fused with its terminal seta. No exopods. Short and robust uropods, peduncle twice as long as pleonite 6 and its endopod, endopod slightly longer than exopod, with 6 setae on inner margin.

Description. Body with weakly calcified integument. Length: 2.6 mm.

Carapace one-third body length, twice as long as high, with pseudorostrum 0.38 of carapace length, ocular lobe reaches its extremity, with some dorsal undulation viewed from lateral side, with few setae, antennal notch marked, lower margin smooth, siphon long.

Antenna 1 basal article of peduncle shorter than rest of articles combined, main flagellum short, 3-articulate, as long as distal article of peduncle, with short aesthetascs, accessory flagellum minute, uniarticulate.

Maxilliped 3 basis with 2 plumose setae on inner distal corner, 3 on outer one (2 much longer), merus with strong tooth and plumose seta on outer margin, carpus shorter than merus, with plumose seta on outer margin, propodus slightly longer than merus, with 2 pappose setae on inner margin, short dactylus with stout long terminal seta.

Pereopod 1 basis less than half as long as appendage, carpus 2nd longest article, dactylus little less than half as long as propodus, with terminal long curved robust seta. Pereopod 2 basis less than half as long as appendage, simple seta on inner margin of merus, carpus little longer than merus, with 2 short robust setae on inner distal corner, dactylus 1.6 times as long as propodus, with long robust terminal seta. Pereopods 3–5 with progressively shorter basis and longer carpus (3 times as long as merus in last pair), dactylus fused with its stout terminal seta. Exopods absent in maxilliped 3 and pereopods 1, 2.

Uropod short and robust, peduncle twice as long as pleonite 6 and its endopod, exopod slightly shorter than endopod, with robust terminal seta, endopod with 6 setae on inner margin and terminal robust seta shorter than in exopod.

Etymology. The species bears the name of the collecting place – Australia.

Distribution. Off Nowra, NSW; 770 m depth.

Remarks. The female of Styloptocumoides australiensis has pereopods as in Styloptocuma poorei but maxilliped 3 has a shorter propodus in S. australiensis ; maxilliped 3 and pereopods 1 and 2 are without exopods, and obviously shorter and larger uropods.

Figures

Figure 64.Styloptocumoides australiensis sp. nov. female holotype: a, body, lateral view; b, antenna 1; c, maxilliped 3; d, pereopod 1; e, pereopod 2; f, pereopod 3; g, pereopod 4; h, pereopod 5; I, pleonite 6 and right uropod. Scale (in mm): a, 0.5; b–e, i, 0.2; f–h, 0.25.