A world-wide review of species of the deepwater crangonid genus Parapontophilus Christoffersen, 1988 (Crustacea, Decapoda, Caridea), with descriptions of ten new species Author Komai, Tomoyuki Natural History Museum and Institute, Chiba, 955 - 2 Aoba-cho, Chuo-ku, Chiba 260 - 8682 (Japan) komai @ chiba-muse. or. jp text Zoosystema 2008 30 2 261 332 journal article 10.5281/zenodo.5393746 1638-9387 5393746 64CFDA2E-D606-4B3D-9A5B-E2FDF9B6974E Parapontophilus cyrton n. sp. ( Fig. 13 ) TYPE MATERIAL . — Holotype : New Caledonia . BIO- CAL, stn CP 69, 23°52’S , 167°58’E , 1220-1225 m , 3.IX.1985 , ♀ 12.6 mm (MNHN-Na 16162). Paratypes : New Caledonia . BIOCAL, stn CP 27, 23°06’S , 166°26’E , 1850-1900 m , 28.VIII.1985 , 1 ♀ 6.7 mm (MNHN-Na 16163). — Stn CP 57, 23°44’S , 166°58’E , 1490-1620 m , 1.IX.1985 , 1 ♂ 6.2 mm , 1 ♀ 10.2 mm (MNHN-Na 16164). — Stn CP 58, 23°56’S , 166°41’E , 2660-2750 m , 1.IX.1985 , 2 ♀♀ 9.0, 10.4 mm (MNHN-Na 16165). — Stn CP 60, 24°01’S , 167°08’E , 1480-1530 m , 2.IX.1985 , 1 ♂ 6.0 mm, 4 ♀♀ 7.1-10.0 mm (MNHN-Na 16166). — Stn CP 62, 24°19’S , 167°49’E , 1395-1410 m , 2.IX.1985 , 2 ♀♀ 9.5, 12.5 mm (MNHN-Na 16167). — Stn CP 69, 23°52’S , 167°58’E , 1220-1225 m , 3.IX.1985 , 1 ♀ 10.6 mm (MNHN-Na.16168). — Stn CP 72, 22°10’S , 167°33’E , 2100-2110 m , 4.IX.1985 , 3 ♀♀ 5.7-7.5 mm (MNHN-Na 16169). BIOGEOCAL, stn CP 214, 22°43.09’S , 166°27.19’E , 1665- 1590 m , 9.IV.1987 , 2 ♂♂ 7.1, 9.0 mm, 2 ♀♀ 7.7, 9.7 mm (MNHN-Na 16170). — Stn CP 265, 21°04.09’S , 167°00.40’E , 1760-1870 m , 18.IV.1987 , 1 ♂ 8.1 mm , 1 ♀ 8.1 mm (MNHN-Na 16171). — Stn CP 272, 21°00.04’S , 166°56.94’E , 1615-1710 m , 20.IV.1987 , 1 ♀ 11.1 mm (MNHN-Na 16172). HALIPRO 2, stn BT 77, Norfolk Ridge, 24°09’S , 167°47’E , 1349-1350 m , 21.XI.1996 , 1 ♀ 11.0 mm (MNHN-Na 16173). ETYMOLOGY. — The Greek kyrton (humpback) refers to the strongly geniculate pleon, showing a humpback appearance. DISTRIBUTION. — Known only from waters around New Caledonia ( Fig. 35 ), 1220-2750 m . DESCRIPTION Rostrum ( Fig. 13 A-D) moderately broad, triangular in dorsal view, 0.15-0.18 of carapace length, directed forward and straight, slightly falling short of or reaching distal margins of corneas; dorsal surface shallowly concave in proximal half; lateral margins armed with 1 or 2 pairs of lateral teeth proximal to midlength. Carapace ( Fig. 13 A-D) 1.50-1.70 longer than wide; anterior epigastric tooth distinctly smaller than posterior epigastric tooth; posterior epigastric and cardiac teeth moderately small; postorbital tooth very small, occasionally reduced to minute tubercle; postorbital ridge low, sometimes obsolete; epibranchial ridge low, but usually well-marked; branchiostegal tooth nearly reaching dorsodistal margin of antennal basicerite. Third pleonal somite ( Fig. 13E ) with tergum somewhat elevated in midline in posterior part and with posterodorsal margin strongly produced, and thus pleon markedly geniculate. Fifth pleonal somite ( Fig. 13E ) smooth on dorsal surface. Sixth pleonal somite ( Fig. 13E, F ) 3.50-3.80 times longer than wide, 2.60-2.90 times longer than deep, dorsal surface with trace of submedian ridges and faint median sulcus; lateral margins slightly concave. Eye ( Fig. 13D ) generally bean-shaped; cornea white or opaque in preservative, semispherical; corneal surface not faceted, but white granules possibly representing remnants of lenses visible throughout integument of cornea as in P. abyssi ; maximal diameter of cornea 0.15-0.18 of carapace length; boundary between cornea and eye-stalk obscurely delineated; eye-stalk slightly constricted near base. Antennular peduncle ( Fig. 13A ) falling short of midlength of antennal scale. Antennal scale ( Fig. 13A ) 0.70-0.80 of carapace length, 4.00-4.50 times longer than wide; lateral margin slightly concave or nearly straight, distolateral tooth reaching or slightly overreaching distal margin of lamella ( Fig. 13G ). FIG. 13. — Parapontophilus cyrton n. sp. ,♀ 12.6 mm, holotype, New Caledonia (BIOCAL, stn CP 69) (MNHN-Na 16162): A , carapace and cephalic appendages, dorsal view; B , carapace, lateral view; C , anterior part of carapace, cornea and basal part of antennae, lateral view; D , anterior part of carapace and eyes, dorsal view; E , third to sixth pleonal somites, lateral view; F , sixth pleonal somite, dorsal view; G , distal part of left antennal scale, dorsal view. Scale bars: A-F, H, 2 mm; G, 1mm. First pereopod overreaching distal margin of antennal scale by 0.15-0.20 length of palm; palm ( Fig.13H ) 3.80-4.00 times longer than wide; cutting edge moderately oblique; pollex moderately small, width including tip of pollex 1.30-1.40 of width proximal to base of pollex; merus with relatively weak dorsodistal tooth. Second pereopod short, reaching or falling short of midlength of merus of first pereopod. Fourth pereopod ( Fig. 13I ) overreaching distal margin of antennal scale by half to full length of dactylus; dactylus subspatulate, 0.50-0.60 of propodal length; carpus 0.80-0.85 of propodal length. Fifth pereopod similar to fourth, slightly falling short of distal margin of antennal scale. Appendix masculina of male second pleopod 0.70-0.80 of appendix interna. Coloration in life Body and pereopods entirely pale reddish-brown. Size Males CL 6.0-9.0 mm; females CL 5.7-11.1 mm . REMARKS The rostrum is usually armed with two pairs of lateral teeth, but either or both of the anterior pairs are rarely missing. This new species appears close to Parapontophilus abyssi , P. occidentalis and P. talismani . These four species have a conspicuous anterior epigastric tooth and the non-faceted cornea. Parapontophilus cyrton n. sp. is characteristic in having the strongly produced posterodorsal margin of the third pleonal tergite. This makes a condition that the pleon is strongly geniculate. The pollex of the first pereopod is less produced in P. cyrton n. sp. than in the other three species (cf. Fig. 13H and Figs 4I , 8J , 9G ). Furthermore, the anterior epigastric tooth on the carapace is distinctly smaller than the posterior epigastric tooth in P. cyrton n. sp. , rather than usually subequal in the latter three species. The distolateral tooth of the antennal scale slightly overreaches the distal margin of the lamella in P. cyrton n. sp. , rather than falling short of or nearly reaching it in the other three species. The present new species is also similar to P. difficilis n. sp. in having opaque or yellowish eyes and a small anterior epigastric tooth on the carapace. However, the structure of the third pleonal tergite and the non-faceted cornea distinguish P. cyrton n. sp. from P. difficilis n. sp. In P. difficilis n. sp. , the posterodorsal margin of the third pleonal tergite is moderately produced; the cornea of the eye is distinctly faceted. The more produced distolateral tooth of the antennal scale also distinguishes P. cyrton n. sp. from P. difficilis n. sp.