Pentaceration bovicornis, 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 : 21-25

Pentaceration bovicornis sp. nov.

Figures 14–16

Type fixation. Holotype, male, here designated.

Etymology. The epithet combines the Latin bovis (genitive of bos = bull) and cornu = horn, alluding to the bulls-horn like lateral head spines.

Material examined. Holotype, 3, 1.30 mm, Australia, New South Wales, Off Eden, 37o0.60'S, 150o20.70'E, 363 m, coarse shell, WHOI epibenthic sled, G.C.B. Poore et al, RV Franklin, 21 July 1986, stn SL 22, NMV J20072 (with 2 slides).

Paratypes (7 specimens). Same data as holotype, NMV J60995 (ƤA, ovigerous, 1.30 mm). Australia, New South Wales, Off Eden, 36o57.40'S, 150o18.80'E, 220 m, muddy shell, WHOI epibenthic sled, G.C.B. Poore et al, RV Franklin, 20 July 1986, stn SL 21, NMV J20071 (3 ovigerous Ƥ). Australia, Victoria, 50 km S of Mallacoota, 38o06.2'S, 149o45.5'E, 188 m, WHOI epibenthic sled, R.S. Wilson, RV Soela, 14 October 1984, stn BSS 228, NMV J20073 (3 ovigerous Ƥ).

Description (male, terminal). Body tapering from pereonite 1 towards pleon; width 0.46 length, widest between pereonites 1 and 2. Head length 0.28 width; length posterior to eyestalks equals anterior length. Frontal margin middle spine short pointed triangle, as long as wide at base, set more ventrad on front margin than lateral spines; lateral spines length 0.8 head length, broad, pointed, forward curved, diverging at approximately 95°. Eyestalks reaching widest point of pereonite 1, club-shaped, curving backward at 40° in distal half, widest in distal half, with broadly rounded apex and few ocelli.

Pereonite 1 lateral parts strongly expanded and dorsally bulging, margins concave in distal 1/3, convex proximally; pereonites 2 and 3 lateral spines diverging at 20°; pereonite 2 with broad forward pointing lateral spines, length approximately 0.3 width of pereonite; pereonite 3 lateral spines broad, triangular, acute, pointing directly laterad, approximately 0.6 length of pereonite 2 spines; pereonite 4 spines with tiny acute points; pereonites 5 and 6 lateral spines of subequal shape, 5 length equal to pereonite 2 spines, 6 slightly larger pointing backwards at 45º, 5 and 6 with posterior lobes overlapping succeeding pereonite; pereonite 7 shorter, triangular, pointed; 5–7 all with thin microdenticulate marginal flanges. Tumaculae present on anterolateral corners of pereonites 6 and 7 ( Fig. 16 C; assumed in male, observed in female).

Pleon length 1.2 width. Pleonite 1 width 0.7 distance between uropods, length 0.2 width. Pleotelson with short neck, proximal and lateral margins evenly merging, lateral margins nearly straight, with 15–18 denticles; distal projection triangular at 90°, 0.23 length of entire pleotelson, apex broadly rounded.

Antennula articles 1 and 2 combined reaching approximately 4/5 along eyestalks; articles 1 and 2 of equal length and width, 1 tubular; 3 slightly longer than 4, 4 half length of equal length 5 and 6.

Antenna article 2 in ventral view approximately four times length of 1, lateral margin broadly convex; 3 width 0.3 length; (remaining articles lost in male, but see Female, below).

Pereopod I basis length 3.57 times width, with few broad, rounded spines anterodistally; ischium 0.6 length of basis, anterior margin with single acute spine; merus with single acute spine on anterior margin; carpus irregularly rectangular, margin distal to robust setae concave with low rounded spine in front of distal robust seta, propodus narrowing distally to insertion of dactylus, with 2 robust seta on opposing margin. Pereopods II–VII slender; pereopod 2 propodus with 3 slender robust setae on posterior margin.

Pleopod I lateral sublobes rounded, partly overlapping, distal lobe twice width of proximal lobe, width 0.3 distance to midline; distal projection length 0.25 pleopod total length, forming 90° angle, with bluntly pointed apices. Pleopod II protopod broadly rounded distally, lateral margin with simple setae; endopod article 2 (stylet) unusually elongate, forming approximately 180° curve before straightening out to reach as far as proximal base of protopod.

Uropods recessed into simple cuticle fold, protopod hidden, exopod vestigial, hidden, with single seta protruding; endopod length 2.2 width.

Female (paratype, ƤA). Head and pleon configuration similar to male. Antenna article 5 length 2.8 times 4; 6 1.8 length of 5; flagellum of 9 articles, first flagellar article approximately 10% longer than second. Pereonite 1 lateral margins evenly rounded; pereonites 2 and 3 lateral spines shorter and broader than in male, diverging at 30°. Pereopod I carpus oval, posterodistal margin straight, robust setae inserted in proximal 1/3 of posterior margin. Pleopod II (operculum) ovoid with concave distal margins, apex broadly rounded, width 0.7 length. Size. Largest female, 1.3 mm; largest male, 1.3 mm.

Distribution. South-eastern Australia, 188– 366 m.

Figures

FIGURE 14. Pentaceration bovicornis sp. nov. H, holotype, 3; F, paratype, ƤA; B, paratype, Ƥ, Stn BSS 228. a, antenna; au, antennula; cv, head ventral view; pl 1, pleopod 1; pt v, pleotelson ventral view; up, uropod. Habitus scale: 0.5 mm.

FIGURE 15. Pentaceration bovicornis sp. nov. Holotype, 3, except F, paratype, ƤA. p 1, 2, 6, pereopods 1, 2 and 6.

FIGURE 16. Pentaceration bovicornis sp. nov. H, holotype, 3; F, paratype, ƤA; C, paratype, Ƥ, cleared in lactic acid, stn SL 21. md, mandible; op, operculum (pleopod 2); pl 2, pleopod 2; tum, tumaculum.