Pentaceration epipedos, 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 : 44-45

Pentaceration epipedos sp. nov.

Figure 31

Type fixation. Holotype, male, here designated.

Etymology. The epithet is the Greek adjective επίπεδος ( epipedos ) meaning flat, alluding to the unusually flattened body of the species.

Material examined. Holotype, 3, 1.72 mm, New Zealand, Campbell Plateau, Pukaki Rise, 49°25'S, 172°07'E, 330–338 m, 7 September 2000, RV Tangaroa , stn TN0009/4, NIWA 29714.

Paratype. Same data as holotype, NIWA 60504 (1 3, 1.65 mm).

Description. Body strongly dorsoventrally flattened, barely tapering from pereonite 2 towards pleon; width 0.47 length, widest between pereonites 6 and 7. Head length 0.22 width; length posterior to eyestalks 1.8 anterior length. Frontal margin middle spine length 0.85 head length; lateral spines 1.4 middle spine length, diverging at 110°; all 3 spines smooth with few short setae. Eyestalks over reaching lateral margin of pereonite 1 with approximately 10% of their length, pointing forward at 10º, slightly narrower near base, apex pointed.

Pereonite 1 lateral margins rounded, with short pointed mid spine; pereonites 2 and 3 with straight, pointed lateral spines of 0.45 pereonite width, 2 pointing forward at approximately 20º, 3 pointing directly laterad; pereonites 2–3 spines diverging at 20 °; pereonite 4 with short, slender, pointed lateral spines; pereonite 5 lateral spines similar to pereonite 3 spines but slightly broader; pereonites 6 and 7 lateral spine broadly triangular, 6 slightly larger than 7, both with narrow translucent flange along anterior margins; pereonites 5 and 6 with long row of simple setae posterolaterally where overlapping succeeding pereonite.

Pleon of equal length and width. Pleonite 1 width 1.25 distance between uropods, length approximately 0.1 width.

Pleotelson proximal and lateral margins evenly merging, lateral margins evenly rounded, with approximately12–14 denticles (both sides somewhat damaged); distal projection triangular at 80°, 0.3 length of entire pleotelson, apex bluntly pointed.

Antennula articles 1 and 2 combined reaching to apex of eyestalks; article 1 1.4 length of 2, tubular; 3 and 4 of subequal length, both 0.6 length of 5 which is 0.85 length of 6.

Antenna article 2 in ventral view approximately 6 times length of 1; 3 width 0.35 length. Pereopod I basis length 2.9 width; ischium 0.65 length of basis; merus with 2 acute spines on anterior margin; carpus oval, distal margin straight; propodus narrowing distally to insertion of dactylus, with 2 robust setae on opposing margin.

Pleopod I lateral sublobes dissimilar, proximal one bluntly triangular, partly overlapping distal one which carry row of simple setae; width 0.28 distance to midline; distal projection length 0.3 pleopod total length, forming acute angle, with bluntly pointed apices. Pleopod II protopod rounded distally; endopod article 2 (stylet) forming 80° curve.

Uropods recessed into simple cuticle hood, protopod and exopod apparently absent; endopod length 3.6 width.

Size. Largest male, 1.72 mm.

Distribution. New Zealand, Campbell Plateau, 330– 338 m.

Figures

FIGURE 31. Pentaceration epipedos sp. nov. Holotype, 3, except M, paratype, 3. a, antenna; au, antennula; cv, head ventral view; p 1, pereopod 1; pl 1 – 2, pleopods 1 and 2; up, uropod. Habitus scale: 0.5 mm.