Vemacumella bacescui, 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 : 170-171

Vemacumella bacescui sp. nov.

Figures 65 , 66

Material examined. Holotype female, Tas., off Freycinet Peninsula, 41°57.50'S, 148°37.90'E, 400 m, coarse shell, WHOI epibenthic sled, M.F. Gomon et al., RV Franklin, 27 Jul 1986 (stn SLOPE 48 ), NMV J53069.

Paratype: 1 female (stn SLOPE 6 ), NMV J53070 .

Diagnosis. Carapace with middorsal row of spines, anterolateral corner strongly serrated, ocular lobe eyeless. Short and robust antenna 1, median article of peduncle with small tubercle. Basis and merus of maxilliped 3 with strong inner serration. Carpus of pereopod 1 2nd longest article, as long as propodus and dactylus combined. Carpus of pereopod 2 with long stout seta on inner distal corner, short dactylus. Uropod peduncle 1.7 times as long as pleonite 6 and 1.3 times as long as endopod, endopod longer than exopod, with 4 stout setae on inner serrated margin.

Description. Body strongly calcified, integument smooth. Length: 2.4 mm.

Carapace 0.33 body length, 1.6 times as long as high, with a median dorsal row of spines reaching frontal lobe, short pseudorostrum meeting in front of ocular lobe, ocular lobe eyeless, antennal notch marked, anterolateral corner strongly serrated, lower margin smooth.

Antenna 1 proximal article of peduncle the longest, median one the shortest, with tubercle provided with pedunculate seta, main flagellum slightly shorter than distal article of peduncle, 3-articulate, accessory flagellum 2-articulate, almost reaching the extremity of basal article of main flagellum.

Maxilliped 3 basis less than half as long as appendage, with 3 strong teeth on inner margin, 2 long plumose setae on outer distal corner, without outer process, merus 2nd longest article, with 2 strong teeth on inner margin, long plumose seta on outer margin of merus and carpus, propodus longer than carpus, with 2 pappose setae on inner margin, dactylus 0.5 propodus length, with 2 stout terminal setae.

Pereopod 1 basis shorter than rest of articles combined, with strong serration on inner margin, tooth on inner margin of ischium, merus longer than ischium, carpus 2nd longest article, as long as propodus and dactylus combined, dactylus with stout slender terminal seta. Pereopod 2 basis shorter than rest of articles combined, merus with simple seta on inner margin, carpus 1.7 times as long as merus, with long stout seta on inner distal corner, dactylus 1.75 times as long as propodus, with numerous short simple setae on both margins, long stout simple terminal seta. Pereopods 3–5 with progressively shorter basis (longer than half of appendage in 3rd pair) and longer carpus (twice as long as merus in 5th pair), dactylus fused with its terminal stout seta. Exopods on maxilliped 3 and pereopods 1, 2.

Uropod peduncle 1.7 times as long as pleonite 6 and 1.3 times as long as endopod, exopod 0.9 times length of endopod, with long robust terminal seta, endopod with 4 stout setae on inner serrated margin and robust terminal seta.

Etymology. The species is dedicated to the memory of the late Mihai C. Băcescu (1908–1999), member of the Romanian Academy, former director of “Grigore Antipa” National Museum of Natural History from Bucharest, one of the highest world authorities on Crustacea Peracarida, as a sign of homage and gratitude for all he offered to his last student.

Distribution. Off Nowra, NSW, off Freycinet Peninsula, Tas.; 400–770 m depth.

Remarks. This is the first record of the genus in the western Pacific ( Australia) and second description of a species of Vemacumella Petrescu. Vemacumella bacescui has in common with Vemacumella heardi Petrescu, 2001 (described from the south-eastern Pacific) a carapace longer than one-third of the body length, five free pereonites, antenna 1 with a tubercle on the median article of the peduncle, accessory flagellum 2- articulate, and relatively short uropods with serrated margins and unequal rami. Vemacumella bacescui differs in having more numerous dorsal spines on the carapace and the basis of maxilliped 3 without an outer process. Other morphological characters are sexually dimorphic, the Australian species being described from a female while the American one is from a male.

Figures

Figure 65. Vemacumella bacescui sp. nov. female holotype: a, body, lateral view; b, body, dorsal view; c, antenna 1; d, maxilliped 3; e, pereopod 1. Scale (in mm): a, 0.5; b, 0.5; c, d, 0.1; e, 0.2.

Figure 66. Vemacumella bacescui sp. nov. female holotype: a, pereopod 2; b, pereopod 3; c, pereopod 4; d, pereopod 5; e, pleonite 6 and left uropod. Scale bar: a–e, 0.2