Pentaceration lancifera, 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 : 10-13

Pentaceration lancifera sp. nov.

Figures 6–7

Type fixation. Holotype, male, here designated.

Etymology. The epithet is composed of the Latin lancea = lance and fero = carry, thus The Lance Carrier, alluding to its long slender posterior pleotelson projection.

Material examined. Holotype, 3, 3.0 mm, Australia, Victoria, South of Point Hicks, 38o25.00'S, 149o0.00'E, 1500 m, compacted clay, WHOI epibenthic sled, G.C.B. Poore et al, RV Franklin, stn SL 27, 22 July 1986, NMV J20065 (with 3 slides).

Paratypes (20 specimens). Same data as holotype, NMV J20066 (9 Ƥ, 5 3). Australia, Victoria, South of Point Hicks, 38o21.90'S, 149o20.00'E, 1000 m, WHOI epibenthic sled, G.C.B. Poore et al., RV Franklin, 23 July 1986, stn SL 32, NMV J20067 (2 Ƥ, 1 3). Australia, Victoria, South of Point Hicks, 38o16.40'S, 149o27.60'E, 800 m, coarse shell, biogenic sediments, WHOI epibenthic sled, M.F. Gomon et al., RV Franklin, 23 July 1986, stn SL 34, NMV J20068 (1 Ƥ, 2 3).

Description (male, holotype). Body, elongate with nearly parallel pereon sides; width 0.25 length, widest between pereonites 2 and 3. Head length 0.25 width, length posterior to eyestalks 2.0 anterior length. Frontal margin mid-spine length twice head length, slender pointed, proximal half with scattered small denticles; lateral spines slightly longer than mid-spine, otherwise similar, diverging at 105°. Eyestalks barely overreaching lateral spines on pereonite 1, pointing directly laterad, tapering to acute point, anterior margins finely denticulate.

Pereonites 1–7 with single middorsal long vertical to slightly backward leaning spine, all of subequal length. Pereonite 1 lateral margins convex with slender, acute spine as long as pereonite mid-length, pointing forward at 45º; pereonites 2–3 lateral spines slender acute, diverging at 40°, approximately as long as 0.85 pereonite width, with marginal small denticles; pereonite 2 spines pointing directly laterad, 3 pointing backward at approximately 45º; pereonite 4 lateral spines approximately as long as those of pereonite 1, but pointing directly laterad; pereonites 5–7 with lateral spines of similar shape but different sizes, spines on 6 similar to pereonite 2 spine, spines on pereonite 5 half length, those of 7 2/3 length of pereonite 6 spines, pereonite 5 spines pointing directly laterad, of 6 backwards at 50º relative to body mid-line, of 7 backwards at approximately 30º.

Pleon length 2.2 width. Pleonite 1 width 0.85 distance between uropods, length 0.23 width. Pleotelson without proximal neck; proximal and lateral margins merging evenly, lateral margins evenly convex, with 11 denticles; distal projection drawn out to long, pointed spine. approximately 0.6 length of entire pleotelson.

Antennula articles 1 and 2 combined reaching to apex of eyestalks; article 1 shorter and slightly wider than 2, tubular; 3 and 4 of equal length, combined approximately as long as 5 (3 and 4 somewhat foreshortened in Fig. 7 , au); 5 length 1.5 of 6.

Antenna article 2 in ventral view 2.75 length of 1, with single distolateral denticle; 3 width 0.2 length, with 1 lateral denticle on proximal bulge and 1 distally; 5 length 4.2 times 4; 6 length 1.6 of 5; flagellum with 9 articles, proximal article length 1.4 article 2.

Pereopod I basis length 4.8 times width, anterodistal margin with long row of small acutely pointed spines; ischium length 0.63 length of basis, length 4 times width; carpus narrowly oval, posterior margin with small translucent flanges at base of robust setae; propodus narrowing distally to insertion of dactylus, with 2 robust setae on opposing margin. Pereopods II–VII slender, basis of 2 and 3 with row of small spines similar to pereopod I; propodus pereopods II and III with 2 slender robust setae on posterior margin, of pereopod VI with 4 robust setae.

Pleopod I distal lateral sublobe prominent, broadly rounded, overlapping smaller, triangular proximal lobe; width 0.23 distance to midline; distal projection length 0.38 pleopod total length, forming acute angle, with bluntly pointed apices. Pleopod II protopod rounded distally, lateral margin with simple setae; endopod article 2 (stylet) forming approximately 125° curve.

Uropods recessed into simple cuticle fold; protopod and exopod apparently absent; endopod length 3 times width.

Female. Females have slightly less strongly developed pereonite 1 lateral parts, but are otherwise similar to males. The operculum is ovoid, pointed with nearly straight distal margins, width 0.68 length.

Size. Largest male, 3.0 mm; largest ovigerous female, 3.45 mm.

Distribution. Australia, eastern Bass Strait slope, 800–1500 m.

Figures

FIGURE 6. Pentaceration lancifera sp. nov. Holotype, 3. p 1, pereopod 1; pl 1 – 2, pleopods 1 and 2; pt v, pleotelson ventral view; up, uropod. Habitus scale: 0.5 mm.

FIGURE 7. Pentaceration lancifera sp. nov. Holotype, 3, except op, paratype, Ƥ. a, antenna; au, antennula; cv, head ventral view; md, mandible; op, operculum (pleopod 2); p 2 and 6, pereopods 2 and 6.