Pentaceration tasmaniensis, Just, Jean, 2011

Just, Jean, 2011, Remarkable Australasian marine diversity: 18 new species in Pentaceration Just, 2009 (Crustacea, Isopoda, Paramunnidae), Zootaxa 2813, pp. 1-54 : 45-47

Pentaceration tasmaniensis sp. nov.

Figure 32

Type fixation. Holotype, female, here designated.

Etymology. The epithet reflects that the species was found off the east coast of Tasmania.

Material examined. Holotype, Ƥ, 2.0 mm, Australia, Tasmania, off Freycinet Peninsula, 42o0.20'S, 148o37.70'E, 720 m, coarse shelly sand, WHOI epibenthic sled, M.F. Gomon et al, RV Franklin, 27 July 1986, stn SL 46, NMV J20063 .

Description (adult female, holotype). Body slightly tapering towards pleon; width 0.4 length, widest between pereonites 2 and 3. Frontal margin mid-spine narrow, pointed, length equals mid length of combined head and pereonite 1; lateral spines 1.7 length of mid-spine, slightly sinuous, diverging at 105°. Eyestalks just overreaching pereonite 1, pointing forward at approximately 10º, straight, narrowly tapering to rounded apex.

Pereonite 1 lateral margins concave in distal half, convex in proximal half; pereonites 2 and 3 lateral spines diverging at 20°; pereonites 2 and 3 and 5–7 with lateral spines of similar shape and length; pereonite 4 with short, pointed lateral spines; all lateral spines with irregular translucent fringes in proximal parts; pereonites 5 and 6 with fringe of simple setae posterolaterally where overlapping succeeding pereonite.

Pleon length 1.28 width. Pleonite 1 width 0.60 distance between uropods, length 0.14 width. Pleotelson proximal and lateral margins merging evenly into each other, lateral margins evenly convex, with 12 denticles (left; right damaged); distal projection triangular at 60°, 0.37 length of entire pleotelson, apex pointed.

Antennula article 1 approximately 0.75 length of 2 ( Fig. 32 habitus; article 2 foreshortened in Fig. 32 au), wider than 2, tubular; 2 overreaching apex of eyestalk with approximately 0.4 of its length.

Antenna article 2 approximately 4 times length of 1; article 3 width 0.25 length, cylindrical; 5 length 2.8 times 4; 6 nearly twice length of 5; flagellum articles 1 and 2 of subequal length.

Pereopod I basis length 3.0 width; ischium 0.87 length of basis; carpus oval, posterior margin with small spine in front of distal robust seta; propodus narrowing distally to insertion of dactylus, with 2 robust setae on opposing margin.

Pleopod II (operculum) ovoid with pointed apex, width 0.73 length.

Uropods recessed into simple cuticle fold, protopod and exopod absent; endopod length 2.8 width.

Size. Largest female, 2.0 mm.

Distribution. Australia, eastern Tasmania, 720 m.

Figures

FIGURE 32. Pentaceration tasmaniensis sp. nov. Holotype, Ƥ. a, antenna; au, antennula; cv, head ventral view; op, operculum (pleopod 2); p 1, pereopod 1; up, uropod. Habitus scale: 0.5 mm.