Parapontophilus caledonicus, Komai, 2008

Komai, Tomoyuki, 2008, A world-wide review of species of the deepwater crangonid genus Parapontophilus Christoffersen, 1988 (Crustacea, Decapoda, Caridea), with descriptions of ten new species, Zoosystema 30 (2), pp. 261-332 : 313-316

Parapontophilus caledonicus n. sp. ( Figs 24 ; 25 )

TYPE MATERIAL. — Holotype: BATHUS 1, stn DE 694, 20°35.9’S, 164°58.3’E, 400-500 m, 17.III.1993, ♀ 2.5 mm, (MNHN-Na 16077).

Paratypes: same data as holotype, 1 ♂ 3.5 mm, 2 ♀♀ 2.3, 3.3 mm (MNHN-Na 16077b).

ETYMOLOGY. — Named after the type locality, New Caledonia.

DISTRIBUTION. — Known only from the type locality in New Caledonia ( Fig. 36 ), 400- 500 m.

DESCRIPTION

Rostrum ( Fig. 24 A-D) relatively short, narrow triangular in dorsal view, 0.14)-0.15 of carapace length, directed forward, straight, falling short of or reaching tips of antennal teeth; lateral margins armed with 1 or 2 tiny teeth on either side, anterior pair, if present, arising at about midlength of rostrum. Carapace ( Fig. 24A, B, D ) 1.40-1.50 times longer than wide; anterior epigastric tooth small, but clearly recognizable; posterior epigastric tooth moderately small, followed by weak middorsal ridge reaching beyond midlength of carapace; cardiac tooth absent; postorbital tooth very small; epibranchial tooth absent; epibranchial ridge absent; branchiostegal tooth moderately small, reaching dorsodistal margin of antennal basicerite.

Third pleonal somite ( Fig. 24F ) with moderately convex tergum and with moderately produced posterodorsal margin. Fifth somite ( Fig. 24F ) rounded dorsally. Sixth somite ( Fig. 24F, G ) 2.90-3.00 times longer than wide, 2.30-2.50 times longer than deep, about 2.00 times longer than fifth somite; dorsal surface rounded.

Ophthalmic appendage ( Fig. 24A, E ) subpyriform; cornea pigmented with brownish gray; corneal surface distinctly faceted with moderately small lenses; maximal diameter of cornea 0.16-0.18 of carapace length; eye-stalk slightly constricted at base; ventromesial face without papilla-like projection. Antennular peduncle ( Fig. 24A ) reaching midlength of antennal scale. Antennal scale ( Fig. 24A ) 0.58-0.60 of carapace length and 2.60-2.80 times longer than wide; lateral margin straight, lamella somewhat produced, distinctly overreaching distolateral tooth.

Palm of first pereopod ( Fig. 25A, B ) 3.30-3.50 times longer than wide; pollex moderately small, width of palm including tip of pollex about 1.30 of width proximal to base of pollex; cutting edge moderately oblique; merus with relatively weak dorsodistal tooth. Second pereopod ( Fig. 25C ) overreaching midlength of merus of first pereopod. Fourth pereopod ( Fig. 25D ) overreaching distal margin of antennal scale by half to full length of dactylus; dactylus elongate, subspatulate, 0.95-1.05 of propodal length; carpus 0.55-0.65 of propodal length. Fifth pereopod similar to fourth, slightly falling short of distal margin of antennal scale.

Appendix masculina of male second pleopod about 0.80 length of appendix interna.

Coloration in life

Unknown.

Size

Male CL 3.5 mm; females CL 2.5-3.3 mm.

REMARKS

The number of lateral rostral teeth is variable in the present new species, although in other species of the group, the number of teeth is constant. In the holotype and the smaller female paratype, the rostrum bears only one pair of lateral teeth; the male paratype has two pairs of lateral teeth, and the other, larger female paratype, have one left and two right teeth.

Morphological similarity suggests that the closest relative of Parapontophilus caledonicus n. sp. is P. juxta n. sp. Nevertheless, P. caledonicus n. sp. is characteristic in having a short rostrum, which only reaches the level of the antennal spines of the carapace. In P. demani and other four new species, the rostrum distinctly overreaches the level of the antennal spines. The dactyli of the fourth and fifth pereopods may be proportionally longer in P. caledonicus n. sp. than in P. demani and other four new species. Furthermore, the sixth abdominal somite seems to be proportionally shorter in P. caledonicus n. sp. than in P. juxta .

Figures

FIG. 24.–– Parapontophilus caledonicus n. sp:A, carapace and cephalic appendages,lateral view;B, rostrum,dorsal view;C, D, rostrum and orbital region of carapace, dorsal view; E, anterior part of carapace, cornea and basal part of antennae, lateral view; F, third to sixth pleonal somites, lateral view; G, sixth pleonal somite, dorsal view; A, B, E-G, ♀ 2.5 mm, holotype, New Caledonia (BATHUS 1, stn DE 694) (MNHN-Na 16077); C, ♂ 3.5 mm, paratype, same data as holotype (MNHN-Na 16077b); D, ♀ 3.3 mm, paratype, same data as holotype (MNHN-Na 16077b). Scale bars: A, E-G, 1 mm; B-D, 0.5 mm.

FIG. 25. –– Parapontophilus caledonicus n. sp., ♀ 2.5 mm,holotype, New Caledonia (BATHUS 1, stn DE 694) (MNHN-Na 16077): A, left first pereopod, lateral view; B, chela of left first pereopod, ventral view; C, left second pereopod, lateral view; D, right fifth pereopod, lateral view. Scale bar: 1 mm.

FIG. 36.— Geographic distribution of Parapontophilus demani (Chace,1984) (●), P. caledonicus n. sp. (▼), P. juxta n. sp. (▲), P. modumanuensis (Rathbun, 1906) (◆), P. psyllus n. sp. (✖), P. sibogae n. sp. (■), and P. stenorhinus n. sp. (✚).