Styloptocuma granulosum, 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 : 164-165

Styloptocuma granulosum sp. nov.

Figures 55 , 56

Material examined. Holotype female. Vic., S of Point Hicks , 38°25'S, 149°00'E, 1500 m, compacted clay, WHOI epibenthic sled, G.C.B. Poore et al., RV Franklin, 22 Jul 1986 (stn SLOPE 27 ), NMV J53067.

Diagnosis. Carapace with short pseudorostrum, antennal notch large, lower margin serrated. Pleon with spines and setae. Antenna 1 with basal article of peduncle longer than rest of articles combined. Merus of maxilliped 3 with tooth on outer margin. Carpus of pereopod 1 longer than propodus, propodus twice as long as dactylus. Carpus of pereopod 2 twice as long as merus, dactylus 3 times as long as propodus. Carpus of pereopod 5 more than 3 times as long as merus. Uropod peduncle 2.1 times as long as pleonite 6, 0.8 endopod length, exopod shorter than endopod, endopod with 6 microeserrate setae on inner margin.

Description. Body with hairy granulous integument. Length: 4.08 mm.

Carapace more than 3rd body length, more elevated on posterior extremity, 1.9 times as long as high, ocular lobe bulky, eyeless, reaching extremity of pseudorostrum, short siphon, antennal notch large, anterolateral corner acute, lower margin strongly serrated, numerous setae.

Antenna 1 proximal article of peduncle 1.65 times length of rest of articles combined, median article without an evident tubercle, main flagellum 3-articulate, twice as long as distal article of peduncle, accessory flagellum minute, uniarticulate.

Maxilliped 3 basis half of appendage, with 2 plumose setae on inner distal corner and 2 much longer on distal outer corner, merus and carpus with tooth and plumose seta on outer margin, carpus longer than merus, propodus 2nd longest article, dactylus half of propodus, with strong stout curved terminal seta.

Pereopod 1 basis less than half as long as appendage, carpus 2.1 times as long as merus, twice as long as propodus, propodus twice as long as dactylus, dactylus with long robust terminal seta, numerous simple setae especially on propodus and dactylus. Pereopod 2 basis less than half as long as appendage, carpus twice as long as merus, with stout seta on inner distal corner, dactylus 3 times as long as propodus, with long simple stout terminal seta. Pereopods 3–5 with progressively shorter basis and longer carpus (carpus more than 3 times as long as merus in last pair), dactylus fused with its stout terminal seta, with inner spine (see detail). Exopods on maxilliped 3 and pereopods 1, 2.

Uropod peduncle 2.1 times as long as pleonite 6, with fine setae on both sides, 0.8 endopod length, exopod slightly shorter than endopod, with robust terminal seta (broken), endopod with 6 microserrate setae on inner margin and terminal robust short simple seta.

Etymology. In Latin “ granulosum ” means granular and describes the integument.

Distribution. S of Point Hicks, Vic.; 1500 m depth.

Remarks. Styloptocuma granulosum differs mainly from other species of Styloptocuma described in this paper in a longer carapace with a smooth upper margin and serrated lower margin. Styloptocuma cristatum Jones, 1984 from the Gulf of Biscay has a longer carapace but with dorsal spines on the carapace, lateral spines on the pleon and uropods with shorter rami.

Figures

Figure 55. Styloptocuma granulosum sp. nov. female holotype: a, body, lateral view; b, antenna 1; c, maxilliped 3; d, pereopod 1. Scale (in mm): a, 0.5; b, 0.2; c, d, 0.5.

Figure 56. Styloptocuma granulosum sp. nov. female holotype: a, pereopod 2; b, pereopod 3; c, pereopod 4; d, pereopod 5; e, pleonite 6 and left uropod. Scale (in mm): a–d, 0.5; e, 0.25.