Parapontophilus gracilis (Smith, 1882)

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 : 271-289

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https://doi.org/10.5281/zenodo.5393746

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scientific name

Parapontophilus gracilis
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Parapontophilus gracilis species group

DIAGNOSIS. — Body slender. Carapace with cardiac and epibranchial teeth. Sixth pleonal somite slightly constricted in dorsal view. Telson subequal to or slightly shorter than sixth pleonal somite. Cornea variable in structure and pigmentation interspecifically; eye-stalk with small papilla-like projection on ventromesial surface. Second pereopod very short, reaching or not reaching midlength of merus of first pereopod.

Parapontophilus gracilis ( Smith, 1882) ( Figs 2 View FIG ; 20A View FIG )

Pontophilus gracilis Smith, 1882: 36 , pl. 7, figs 2, 2a-c, 3, 3a (type locality: two syntypes came from two different stations in the northwestern Atlantic: E of South Carolina, 225 fathoms; and off Martha’s Vineyard, 458 fathoms); 1884: 196; 1886: 654, pl. 11, figs 1, 1a, 2. — Ortmann 1895: 183, 18. — Faxon 1896: 157. — Stebbing 1905: 94, pl. 25; 1910: 383. — Kemp 1916: 357. — De Man 1920: 260 (key), 264. — Barnard 1950: 806, fig. 153a-h. — Crosnier & Forest 1968: 1145; 1973: 242, fig. 79e, f. — Pequegnat 1970: 113. — Pequegnat et al. 1971: 10. — Kensley 1972: 64, fig. 30a, b. — Dardeau & Heard 1983: 24, figs 2c, 13. — Takeda & Okutani 1983: 72, unnumbered fig. — Macpherson 1983: 66. — Garcia Raso 1996: 736.

Pontophilus gracilis gracilis – Chace 1984: 47 (key), fig. 23b.

Parapontophilus gracilis – d’Udekem d’Acoz 1999: 133. — Davie 2002: 239 (in part).

? Pontophilus gracilis – Wood-Mason in Wood-Mason & Alcock 1891: 361. — Alcock 1899: 75; 1901: 115. — Balss 1925: 296.

Not Pontophilus gracilis Bate, 1888: 487 , pl. 87. See “Remarks” of Parapontophilus abyssi ( Smith, 1884) .

Not Pontophilus gracilis – Rathbun 1906: 910. See “Remarks”.

TYPE MATERIAL. — Syntypes: Blake , stn 315, E of South Carolina, 32°18.20’N, 78°43’W, 225 fathoms (about 405 m), 1880, 1 ♀ 6.1 mm ( MCZ) GoogleMaps ; off Martha’s Vineyard, Albatross, stn 1029, 485 fathoms (about 873 m), 1 ♂ ( USNM). Not examined .

OTHER MATERIAL EXAMINED. — Gulf of Mexico. Blake, off St Vincent , 553 m, 1 ♂ 6.5 mm (MNHN-Na 1199). — Stn 43, S of Dry Toriugas , Antilles , 24°08’N, 82°51’W, 610 m, VIII.1877, 1 ♂ 6.4 mm, 4 ♀♀ 2.4-7.2 mm, 1 ovig. ♀ 5.4 mm (MNHN-Na 1189) GoogleMaps ; 2 ♀♀ 5.2, 8.8 mm, 1 ovig. ♀ 6.1 mm (MNHN-Na 1198). — Stn 47, off mouth of the Mississippi, 28°42’S, 88°40’W, 578 m, VIII.1878, 6 ♂♂ 3.9-4.7 mm, 13 ♀♀ 4.3-5.5 mm (MNHN-Na 1194). — Stn 48, offmouth of Mississippi, 28°47.30’N, 88°41.30’W, 959 m, VIII.1878, 1 ♂ 4.4 mm (MNHN-Na 1200). Northeastern Atlantic. Iberia-Morocco Gulf , BALGIM RV Cryos , stn CP 91, 34°22’N, 07°25’W, 948 m, 7.VI.1984, 1 ♀ 5.1 mm (MNHN-Na 11917).— Sahara , Talisman , stn 72, 882 m, 2 ♀♀ 6.3, 7.0 mm (MNHN-Na 1190). — Stn 76, 25°39’N, 16°06’W, 1435- 1056 m, 9.VII.1883, 2 ♀♀ 7.1, 7.5 mm (MNHN-Na 1197). — Stn 83, 11.VII. 1883, 930 m, 3 ♀♀ 7.9-11.3 mm (MNHN-Na 1193).— Stn 84, 22°54’N, 17°26’W, 860 m, 12.VII.1883, 3 ♀♀ 7.5-10.4 mm (MNHN-Na 1195). — Stn 88, 22°52’N, 17°23’W, 830 m, 12.VII.1882, 4 ♀♀ 7.8-11.0 mm (MNHN-Na 1192). — Senegal , 15°51’N, 17°05’W, 19.XII.1958, 2 ♂♂ 5.0, 5.1 mm, 6 ♀♀ 5.4-10.0 mm (MNHN-Na 5258). Southeastern Atlantic. Congo , Geronimo , stn 2-240, 04°08’S, 10°08’E, 1134 m, 8.IX.1963, shrimp trawl, 2 ♀♀ 8.4, 9.0 mm (MNHN-Na 1187). — Cabinda , Ombango , 05°04’S, 10°13’E, 805 m, 17.III.1967, 1 ♀ 7.0 mm (MNHN-Na 16220). — Stn CH 394-53 , 05°08’S, 11°24’E, 600 m, 20.IX.1967, 1 ♀ (badly damaged) (MNHN-Na 16221). — Stn CH 394-55 , 05°08’S, 11°22’E, 795-805 m, 20.IX.1967, 2 ♀♀ 8.3, 10.9 mm (MNHN-Na 16222). — Angola , Ombango , stn CH 398 , 11°57’S, 13°15’E, 825-1000 m, 16.IV.1968, 1 ♀ crashed (MNHN-Na 16223) GoogleMaps ; 4 ♀♀ 9.6-10.7 mm (MNHN-Na 16224). — Stn CH 417 , 05°06’S, 11°18’E, 800-900 m, 18.XI.1969, 4 ♀♀ 7.8-9.2 mm (MNHN-Na 16225) GoogleMaps .

DISTRIBUTION. — Known with certainty only from the Atlantic Ocean ( Fig. 34 View FIG ), 578-1435 m.

DESCRIPTION

Rostrum ( Fig. 2 View FIG A-D) very slender, nearly spiniform, 0.20-0.30 of carapace length, directed forward, overreaching midpoint of corneas, but not reaching distal margins of corneas; dorsal surface shallowly concave in proximal half; lateral margins armed with 1 or 2 tiny teeth on either side (lateral teeth occasionally rudimentary). Carapace ( Fig. 2 View FIG A-D) 1.30-1.40 times longer than wide, anterior epigastric tooth greatly reduced to minute denticle or absent; posterior epigastric and cardiac teeth moderately small, cardiac tooth arising from about two-thirds of carapace length; postorbital tooth minute, occasionally absent; epibranchial tooth moderately small; epibranchial ridge usually obsolescent; branchiostegal tooth slightly falling short of dorsodistal margin of antennal basicerite.

Third pleonal somite ( Fig. 2E View FIG ) with moderately convex tergum and moderately produced posterodorsal margin; fourth and fifth somites ( Fig. 2E View FIG ) rounded dorsally; sixth somite ( Fig. 2F, G View FIG ) 3.10-3.50 times longer than wide, 2.30-2.50 times as long as deep, about 1.60 length of fifth somite, with trace of median sulcus on dorsal surface.

Eye ( Fig. 2A View FIG ) generally bean-shaped; cornea darkly pigmented (colour entirely brown in preservative), maximal diameter 0.25-0.30 of carapace length; corneal surface well faceted ( Fig. 20A View FIG ), covered with fine lenses; boundary between cornea and eye-stalk clearly delineated; eye-stalk hardly constricted near base; papilla-like projection on mesial face small. Antennular peduncle reaching midlength of antennal scale. Antennal scale ( Fig. 2A View FIG ) 0.60-0.70 times as long as carapace, 3.10-3.50 times as long as wide; lateral margin concave, distolateral tooth nearly reaching distal margin of lamella.

Palm of first pereopod ( Fig. 2H View FIG ) 3.90-4.20 times longer than broad; cutting edge moderately oblique; pollex moderately large, width of palm including tip of pollex 1.40-1.50 of width of palm 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. 2I View FIG ) overreaching distal margin of antennal scale by full length of dactylus; dactylus subspatulate, 0.70-0.80 of propodal length; carpus 0.70-0.80 of propodal length. Fifth pereopod ( Fig. 2J View FIG ) similar to fourth, reaching distal margin of antennal scale by tip of dactylus. Appendix masculina of male second pleopod 0.60-0.70 length of appendix interna.

Coloration in life

Entirely light brown, darker on cephalothorax; corneas dark brown according to the colour photograph of Takeda & Okutani (1983).

Size

Males CL 3.9-6.5 mm; females CL 2.4-11.3 mm, ovigerous females CL 5.4-6.1 mm.

REMARKS

As noted under the account of Parapontophilus abyssi , Pontophilus gracilis Bate, 1888 is a junior homonym of Pontophilus gracilis Smith, 1882 . Bate’s (1888) taxon is identical with Parapontophilus abyssi .

Size and development of the lateral teeth on the rostrum varies individually. The anterior pair is occasionally absent, and even the posterior pair is sometimes very small.

Parapontophilus gracilis can be separated easily from most of the other congenerics by the large eye. The maximal diameter of the cornea is 0.25-0.30 of the carapace length in P.gracilis , while in all other species but P.profundus it does not exceed 0.22. Differences between P. gracilis and P. profundus are discussed un- der account of the latter species. The rudimentary anterior epigastric tooth on the carapace and the wellpigmented and finely faceted cornea also separate P. gracilis from P. abyssi , P. cyrton n. sp., P. difficilis n. sp., P. longirostris n. sp., and P. talismani .

This species has not been found in samples from localities outside the Atlantic Ocean during the present study. Chace (1984) remarked that the specimens recorded as Pontophilus gracilis from Hawaii by Rathbun (1906) could not be separated from his Pontophilus gracilis abyssi (= Parapontophilus geminus n. sp.). This clearly suggests that Rathbun’s (1906) Hawaiian material does not represent Parapontophilus gracilis . Nevertheless, it is still impossible to determine what species is actually represented by Rathbun’s material without examination of her specimens. The records of this species from the Indian Oceans by Wood-Mason & Alcock (1891), Alcock (1899, 1901) and Balss (1925) also need to be verified.

Parapontophilus abyssi ( Smith, 1884) ( Figs 3 View FIG ; 4 View FIG A-D; 20B)

Pontophilus abyssi Smith, 1884: 363 (type locality: east of Chesapeake Bay, USA, 3506 and 4060 m); 1886: 653, pl. 11, figs 3, 3a, 4, 5. — de Saint Laurent 1985: 47. — Williams et al. 1989: 20 (list).

Pontophilus gracilis Bate, 1888: 487 (in part), pl. 87 (type locality: South Atlantic Ocean about 900 km WNW Tristan da Cunha, 3475 m). Not Pontophilus gracilis Smith, 1882 .

Pontophilus challengeri Ortmann, 1893: 49 (substitute name for Pontophilus gracilis Bate, 1888 ); 1895: 185 (in part). — Kemp 1911: 12 (in part). — Holthuis 1951: 16. — Zarenkov 1969: 80 (list). — Crosnier & Forest 1973: 248, 249, fig. 80e-g.

Pontophilus batei Faxon, 1893: 200 (substitute name for Pontophilus gracilis Bate, 1888 ); 1895: 131 (in part).

Pontophilus indica – Calman 1939: 219 (in part).

Pontophilus occidentalis var. indica – Kensley 1968: 319, figs 18, 19; 1972: 64, fig. 30c, d. Not Pontophilus occidentalis var. indica de Man, 1918 .

Pontophilus indicus – Zarenkov 1969: 80 (list; in part).

Pontophilus occidentalis – Kensley 1981: 28 (list). Not Pontophilus occidentalis Faxon, 1893 .

Parapontophilus abyssi – d’Udekem d’Acoz 1999: 133.

? Pontophilus challengeri – Richardson & Yaldwyn 1958: 41, fig. 48. See “Remarks”.

? Parapontophilus gracilis abyssi – Davie 2000: 240.

Not Pontophilus gracilis abyssi – Chace 1984: 47 (key), 49, figs 16, 17, 23c (= Parapontophilus geminus n. sp.).

Not Pontophilus gracilis abyssi – Allen & Butler 1994: 440 (= Parapontophilus longirostris n. sp.).

Not Pontophilus cf. abyssi – Garcia Raso 1996: 736.

TYPE MATERIAL. — Syntypes of Pontophilus abyssi Smith, 1884 : Albatross , stn 2097, E of Chesapeake Bay, USA, 37°56.20’N, 70°57.30’W, 3451 m, 1.X.1883, 1 ♀ ( USNM 7023 View Materials ) GoogleMaps ; 1 ♂, 1 ovig. ♀ ( USNM 7025 View Materials ). — Stn 2098, 37°40.30’N, 70°37.30’W, 3998 m, 01.X.1883, 1 ♂ ( USNM 7024 View Materials ) 1 ovig. ♀ (10.8 mm; USNM 7025 View Materials ) has been examined GoogleMaps . Holotype of Pontophilus gracilis Bate, 1888 : Challenger , stn 133, near Tristan da Cunha, Mid-Atlantic Ridge, 35°41’S, 20°55’W, 3420 m, 11.X.1873, ♀ 16.2 mm ( BMNH 1888.22 ). Examined GoogleMaps .

OTHER MATERIAL EXAMINED. — Northwestern Atlantic. Albatross, stn 2226, 37°00’N, 71°54’W, 3638 m, 1 ♂ 11.7 mm, 1 ovig. ♀ 15.0 mm ( USNM 8600). — Advance II, stn EPA-78-1-13, off Virginia, 37°46.11’N, 70°27.50’W, 3920 m, 26. VI.1978, 2 ♂♂ c. 12.0, 12.1 mm, 4 ♀♀ 10.5-15.0 mm ( USNM 222198). Northeastern Atlantic. N of Azores, Talisman 1883, stn 133, 42°15’N, 23°17’W, 3965-4060 m, 24.VIII.1883, 1 ♂ (damaged), 1 ♀ 13.1 mm (MNHN-Na 4316). — Stn 135, 43°15’N, 19°20’W, 4165 m, 25.VIII.1883, 1 ♂ 12.0 mm (MNHN-Na 4317). N of Madeira, ABYPLAINE, stn CP 11, 34°06.1’N, 17°06.3’W, 4270 m, 30. V.1981, 2 ♂♂ 11.8, 12.2 mm, 5 ♀♀ 9.7-13.0 mm (MNHN-Na 11026). — Stn CP 12, 34°05.2’N, 17°06.9’W, 4260 m, 30. V.1981, 2 ♂♂ 10.1, 10.6 mm, 1 ♀ 13.7 mm (MNHN-Na 11027). Off France, BIOGAS V, stn 5 CP 06, 44°20’N, 04°54,3’W, 4460 m, 20. VI.1974, 2 ♂♂ 12.2, 13.2 mm (MNHN-Na 4322). — INCAL, stn WS 10, 47°27.3’N, 9°36.9’W, 4354 m, 11.VIII.1976, 1 ♀ 14.7 mm (MNHN-Na 4319). — Stn CP 15, 47°26.4’N, 9°35.3’W, 4201 m, 10.VIII.1976, 2 ♀♀ 14.3, 15.2 mm (MNHN-Na 4318). Southeastern Atlantic. Gulf of Guinea, WALDA, stn CY 20, 02°39.5’S, 05°43.2’E, 4088 m, 27.VII.1971, 1♀ 12.3 mm (MNHN-Na 5259). — Data not indicated, 2 ♀♀ 13.9, 14.4 mm (MNHN-Na 4323). Western Indian Ocean. Geyser Bank, Glorieuses Islands, BENTHEDI, Suroît, stn CH 82, 11°59.8’S, 45°42.6’E, 3450 m, 1.IV.1997, 1 ♀ 16.2 mm (MNHN-Na 16081). — Stn CH 87, 11°44’S, 47°35’E, 3716 m, 3.IV.1977, 6 ♀♀ 13.1-17.8 mm (MNHN-Na 16082). — Stn CH 90, 11°44’S, 47°30’E, 3700 m, 4.IV.1977, 1 ♂ (not measured) (MNHN-Na 9876). Natal and South Madagascar basins, SAFARI 1, stn 06, CP 02, 30°25.3’S, 39°49.8’E, 4905 m, 24.VIII.1979, 1 ♀ 14.4mm (MNHN-Na 9791). — Stn 18, CP 10, 29°50.9’S, 48°35.5’E, 3668-3800 m, 4.IX.1979, 2 ♂♂ 12.8, 13.4 mm, 3 ♀♀ 13.7-15.6 mm (MNHN-Na 9813).

Madagascar ( NW coast), Vauban, stn CH 138, 13°48.8’S, 47°29.4’E, 1800-2000 m, 27.II.1975, 1 ovig. ♀ 10.3 mm (MNHN-Na 16083).

Mid-Indian Basin. SAFARI 2, stn 02, CP 03, 05°48’N, 78°43’E, 3450 m, 1 ♀ 19.0 mm (MNHN-Na 9836). — Stn 03, CP 04, 07°07’N, 79°00’E, 2475 m, 1 ♀ 12.0 mm (MNHN-Na 9837). — Stn 17, CP 15, 06°17’S, 89°11’E, 2895-3000 m, 1 ♀ 12.0 mm (MNHN-Na 9839).

DISTRIBUTION. — Temperate to tropical regions in the Atlantic Ocean and Indian Ocean ( Figs 34 View FIG ; 35 View FIG ), 1800-5852 m.

DESCRIPTION

Rostrum ( Figs 3 View FIG A-D; 4D) moderately broad, triangular in dorsal view, 0.15-0.20 of carapace length, directed slightly upward or forward, reaching or slightly overreaching anterior margins of corneas; dorsal surface shallowly concave in basal half; lateral margins armed with 1 or 2 small teeth proximal to midlength. Carapace ( Fig. 3 View FIG A-D) 1.60-1.70 times as long as wide, with 1 anterior epigastric tooth being subequal to or slightly smaller than posterior epigastric tooth; posterior epigastric and cardiac teeth moderately large, latter arising from 0.60-0.70 of carapace length; postorbital tooth very small; epibranchial ridge low, occasionally obsolete; branchiostegal tooth usually falling short of dorsodistal margin of antennal basicerite.

Third pleonal somite ( Fig. 3E View FIG ) with moderately convex tergum and moderately produced posterodorsal margin; fifth somite rounded dorsally; sixth somite ( Fig. 3E, F View FIG ) 3.50-3.90 times longer than wide, 2.60-2.80 times longer than deep; dorsal surface ( Fig. 3F View FIG ) with trace of submedian ridges and faint median sulcus.

Eye ( Fig. 3A, G View FIG ) generally bean-shaped; cornea opaque or light yellow, maximal diameter 0.15-0.17 of carapace length; corneal surface not faceted ( Fig. 20B View FIG ), but white granules possibly representing remnants of lenses visible through integument of cornea; boundary between corneal region and eye-stalk obsolescent; eye-stalk not markedly constricted; papilla-like projection on mesial face small. Antennular peduncle ( Fig. 3A View FIG ) falling short of midlength of antennal scale. Antennal scale ( Fig. 3A View FIG ) 0.60-0.70 of carapace length, 3.80-4.10 times longer than wide; lateral margin slightly concave or nearly straight, distolateral tooth nearly reaching distal margin of lamella.

Palm of first pereopod ( Fig. 3H View FIG ) 3.50-3.80 times longer than wide; cutting edge moderately oblique; pollex relatively large, width of palm including tip of pollex 1.40-1.50 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. 3I View FIG ) overreaching distal margin of antennal scale by half to full length of dactylus; dactylus subspatulate, 0.55-0.60 of propodal length; carpus about 0.80 of propodal length. Fifth pereopod similar to fourth pereopod, slightly falling short of distal margin of antennal scale. Appendix masculina of male second pleopod 0.60-0.70 length of appendix interna.

Coloration in life

Unknown.

Size

Males CL 11.7-13.2 mm; females CL 9.7-17.8 mm, ovigerous females CL 10.8-15.0 mm.

REMARKS

The anterior pair of the lateral teeth on the rostrum is sometimes absent, although the posterior pair is always distinct in all the specimens examined.

Parapontophilus abyssi closely resembles two other abyssal congeners, P. occidentalis and P. talismani . Differences among the three species are discussed under “Remarks” of P. talismani .

Specimens from various localities in the Atlantic and Indian oceans are consistent in every diagnostic features. The synonymy of the two replacement names for P. gracilis Bate, 1888 , Pontophilus challengeri Ortmann, 1893 and Pontophilus batei Faxon, 1893 , with Parapontophilus abyssi , proposed by Chace (1984), was confirmed (for detail of the publication date of the two names, see Chace [1984: 50]), because the holotype of the taxon established by Bate (1888) and the syntypes of P. abyssi are undoubtedly conspecific. Reexamination of the type series of Pontophilus challengeri has revealed that four species are confounded in the type series. The true P. abyssi is represented only by the holotype from the southwestern Atlantic near Tristan da Cunha (Challenger, stn 133) ( Fig. 4 View FIG A-D). The six paratypes from off New Zealand (Challenger, stn 168, 40°28’S, 177°43’E, 1980 m, 8.VII.1874, 2 ♂♂ 9.8, 10.4 mm, 4 ♀♀ 9.3-11.3 mm, BMNH 1888.22) cannot be referred to any species treated in this paper. This undescribed species can be distinguished from other species of the genus by a suite of characters, including the small but conspicuous anterior epigastric tooth on the carapace, the noticeably concave lateral margin of the antennal scale and the strongly produced lamella of the antennal scale, which overreaches the distolateral tooth. Chace (1984) noted that the cornea was relatively small and spherical in the six paratypes from New Zealand. Unfortunately, these six paratypic specimens are now in poor condition, because they once had once dried. Therefore, formal description of a new species is delayed in the hope that an additional material will be obtained in the future. The paratype from the Torres Strait in Indonesia (Challeng- er, stn 184) is referred to P. geminus n. sp., as the specimen shows all diagnostic features of the latter new species. The two paratypes from the Celebes Sea (Challenger, stn 198) are very similar to P. abyssi ( Fig. 4 View FIG E-I). However, the structure of the eye of those two specimens is different from that of P. abyssi . In the former, the cornea is relatively small, the diameter is 0.13 of the carapace length, in contrast 0.15-0.17 in P. abyssi ; the boundary between the cornea and eye-stalk is less oblique in the two paratypes of P. challengeri from the Celebes Sea than in P. abyssi ; the proximolateral angle of the eye-stalk is slightly expanded in a flange in the two paratypes of P. challengeri from the Celebes Sea ( Fig. 4G View FIG ), but such a flange is not seen in the specimens identified with P. abyssi ( Fig. 3D, G View FIG ). There would seem to be little doubt that the two specimens from the Celebes Sea represent a species other than P. abyssi . However, more specimens are needed to draw out definite conclusion on the taxonomic identity of these two specimens.

Calman (1939) identified specimens from a wide bathymetric range in the western Indian Ocean (494-2926 m) collected during John Murray Expedition with Pontophilus indicus established by de Man (1918). He clearly mentioned that the variation in the size of the anterior epigastric tooth and of the corneal colour depends of the depths. Although Calman’s specimens have not been examined, there is little doubt that specimens from abyssal depths greater than 2000 m (stn 26, 2312 m; stn 185, 2000 m; stn 120, 2926 m; stn 155, 2249 m; and stn 162, 1829- 2051 m) represent Parapontophilus abyssi .

Richardson & Yaldwyn (1958) mentioned the presence of Pontophilus challengeri in waters around New Zealand. Although the given illustration is rather diagrammatic, a well-developed anterior epigastric tooth is clearly depicted in the illustration ( Richardson & Yaldwyn 1958: fig. 48). However, the shape of the corneas illustrated by the authors is quite different from those of Parapontophilus abyssi . In all probability, Pontophilus challengeri mentioned by Richardson &Yaldwyn (1958) is the undescribed species represented by six paratypic specimens of P. challengeri from off New Zealand.

Chace (1984) reported Pontophilus gracilis abyssi from Indonesia based on three Albatross specimens. The diagnosis and illustrations given by Chace (1984) agree closely with P. geminus n. sp. in every aspect, including the relatively small corneas and the relatively short branchiostegal tooth.

Allen & Butler (1994) reported Parapontophilus abyssi (as Pontophilus ) from Sio Guyot, Mid-Pacific mountains. Examination of the three specimens in the collection of CBM has shown the existence of P. longirostris n. sp. on the same sea mountain where Allen & Butler (1994) recorded P. abyssi . Therefore, the record of Allen & Butler (1994) is referred to P. longirostris n. sp.

A specimen from the Ibero-Moroccan waters in the eastern Atlantic, provisionally identified with Pontophilus abyssi by Garcia Raso (1996), has been reexamined. It does not represent Parapontophilus abyssi , but a species closely resembling P.longirostris n. sp. In this specimen, the rostrum is abnormally missing. Therefore, final determination of its specific identity is deferred in the hope that additional specimens from the Atlantic Ocean will become available.

Davie (2002) cited a record of Parapontophilus gracilis abyssi from Queensland, Australia, but no information on the morphology is provided. During this study, the occurrence of P. abyssi from the western Pacific has not been confirmed. Therefore, Davie’s record is questionably included in the synonymy.

Parapontophilus junceus ( Bate, 1888) ( Figs 5 View FIG ; 6A, B View FIG ; 20C View FIG )

Pontophilus junceus Bate, 1888: 491 , pl. 88, figs 2-4 (type locality: Moro Gulf, east of Basilan Strait, Mindanao, Philippines, 457 m).

Pontophilus occidentalis var. indica de Man, 1918: 161 (in part) (type locality: Bali Sea , Indonesia, 538 m; here restricted by lectotype designation); 1920: 264 (in part).

Pontophilus indicus – Calman 1939: 219 (in part). — Zarenkov 1969: 80 (list; in part).

Pontophilus gracilis junceus – Chace 1984: 47 (key), 53 (in part). — Takeda & Hanamura 1994: 30. — Sakaji 2001: 211.

? Parapontophilus gracilis junceus – Hanamura & Evans 1996: 15. — Davie 2002: 240.

? Pontophilus junceus – Balss 1925: 296.

? Pontophilus indicus – Richardson & Yaldwyn 1958: 41, fig. 46.

? Pontophilus gracilis junceus – Burukovsky 1990: 209.

Not Pontophilus occidentalis var. indica – Kensley 1968: 319, figs 18, 19; 1972: 64, fig. 30c, d (= Parapontophilus abyssi ( Smith, 1884)) .

Not Pontophilus gracilis junceus – Chace 1984: figs 20-22, 23d (= Parapontophilus difficilis n. sp.).

TYPE MATERIAL. — Holotype of Pontophilus junceus Bate, 1888 : Challenger , stn 200, Moro Gulf, Mindanao, Philippines, 06°47’N, 122°28’E, 457 m, 20.X.1874, ♀ 8.2 mm ( BMNH 1888.22 ). Examined. GoogleMaps

Lectotype of Pontophilus occidentalis var. indica de Man, 1918 (herein selected): Siboga , stn 316, Bali Sea, Indonesia, 07°19.4’S, 116°49.5’E, 538 m, 19.II.1900, ovig. ♀ 8.7 mm ( ZMA). Examined.

Paralectotypes of Pontophilus occidentalis var. indica : Siboga , stn 45, Flores Sea, 07°24’S, 118°15.2’E, 794 m, 6.IV.1899, 1 ♀ 6.3 mm, 2 ovig. ♀♀ 7.6, 8.3 mm ( ZMA). — Same data as lectotype, 2 ♀♀ 6.1, 7.2 mm, 3 ovig. ♀♀ 8.7, 9.9 mm (one individual badly damaged) ( ZMA). Examined.

OTHER MATERIAL EXAMINED. — Japan. Off Wabuka, Kushimoto, Kii Peninsula, 550 m, 20.X.1994, dredge, coll. S. Nagai, 1 ♂ 5.8 mm ( CBM-ZC 3027).

East China. RV Yoko-maru 1993 cruise, 30°26.8’N, 128°18.6’E, 693 m, 7.IX.1993, trawl, 2♂♂ 6.2, 6.4 mm, 1 ♀ 7.9 mm ( CBM-ZC 3028).

Taiwan. TAIWAN 2001, stn CP 108, 24°48.2’N, 122°07.7’E, 295-337 m, 20. V.2002, 1 ovig. ♀ 6.4 mm (MNHN-Na 16084). — Stn CP 115, 24°53.87’N, 122°02.05’E, 381-440 m, 21. V.2001, 1 ♂ 7.2 mm ( NTOU). — Stn CP 132, 22°20.98’N, 120°06.73’E, 690-700 m, 21.XI.2001, 4♀♀ 7.4-8.4 mm ( NTOU). — Stn CD 134, 22°16.56’N, 120°06.11’E, 736-1040 m, 22.XI.2001, 1 ♀ 7.9 mm ( NTOU). — Stn CD 137, 22°12.92’N, 120°25.93’E, 316-477 m, 23.XI.2001, 4♂♂ 4.0-7.0 mm, 3 ♀♀ 6.2-7.4 mm ( NTOU). — Stn CP 139, 22°10.7’N, 120°14.1’E, 718-852 m, 23.XI.2001, 1 ♀ 8.0 mm ( NTOU). — Stn CD 140, 22°11.40’N, 120°22.58’E, 452- 280 m, 24.XI.2001, 2 ♂♂ 5.4, 5.9 mm, 2 ♀♀ 6.8, 7.2 mm ( NTOU).

TAIWAN 2003, stn CD 210, 24°28.99’N, 122°12.79’E, 500-1183 m, 1. VI.2003, 2 ♀♀ 7.3 mm (one individual damaged) ( NTOU). — Stn CD 230, 22°19.32’N, 120°30.30’E, 795-840 m, 30.VIII.2003, 1 ♂ 5.7 mm ( NTOU).

TAIWAN 2004, stn CP 271, 20°20.19’N, 120°7.02’E, 703-785 m, 28.XII.2004, 1 ♀ 8.7 mm ( NTOU).

TAIWAN 2005, stn CP 299, 22°16.25’N, 120°03.08’E, 806-835 m, 11.VIII.2005, 1 ♀ 6.3 mm ( NTOU). — Stn CP 324, 20°37.53’N, 117°50.62’E, 1293-1499 m, 20.VIII.2005, 2 ♀♀ 7.6, 8.5 mm ( NTOU). — Stn PCP 332, 22°13.97’N, 120°00.22’E, 961-1026 m, 5.X.2005, 4♀♀ 7.6-8.5 mm ( NTOU). — Stn PCP 333, 22°13.61’N, 120°01.91’E, 889-1037 m, 5.X.2005, 4 ♀♀ 6.9-8.2 mm ( NTOU). — Stn PCP 334, 22°14.16’N, 119°59.25’E, 994- 975 m, 5.X.2005, 4 ♀♀ 6.6-7.6 mm ( NTOU). — Stn PCP 342, 1 ♀ 7.1 mm ( NTOU).

TAIWAN 2006, stn PCP 341, 6 ♀♀ 7.1-8.2 mm ( NTOU). — Stn PCP 343, 2 ♀♀ 7.4 mm, damaged ( NTOU). — Stn CP 362, 1 ♀ 7.5 mm ( NTOU).

Philippines. MUSORSTOM 2, stn CP 25, 13°39.0’N, 120°42.6’E, 550- 520 m, 23.XI.1980, 1 ♀ 9.1 mm (MNHN-Na 5315). — Stn CP 78, 13°49.1’N, 120°28.0’E, 441-550 m, 1.XII.1980, 1 ♀ 7.1 mm (MNHN-Na 5319).

MUSORSTOM 3, stn CP 118, 11°58’N, 121°06’E, 448-466 m, 3. VI.1985, 1 ♀ 8.0 mm (MNHN-Na 16085).

PANGLAO 2005, Bohol Sea, stn CP 2333, Maribojoc Bay, 09°38.2’N, 123°43.5’E, 596- 566 m, mud, 22. V.2005, 3♀♀ 6.1-7.0 mm ( NTOU). — Stn CP 2334, similar locality, 09°37.46’N, 123°40.22’E, 631-659 m, sand, 22. V.2005, 5 ♀♀ 3.9-7.1 mm ( NTOU). — Stn CP 2388, 09°26.9’N, 123°34.5’E, 762-767 m, sand-mud, 30. V.2005, 1 ♀ 6.1 mm ( NTOU). — Stn CP 2394, off Balicasag Island, 09°28.6’N, 123°40.0’E, 566-787 m, sand-mud, 2♀♀ 4.5, 7.0 mm ( NTOU). — Stn CP 2398, similar locality, 09°32.6’N, 123°40.5’E, 731-741 m, sand, 31. V.2005, 1 ♀ 6.3 mm ( NTOU).

Indonesia. KARUBAR, Kai Islands , stn CP 17, 05°15’S, 133°01’E, 459- 439 m, 24.X.1991, 2 ♀♀ 7.9, 8.3 mm (MNHN-Na 16086). — Stn CP 19, 05°15’S, 133°01’E, 605- 576 m, 25.X.1991, 1 ♀ 7.6 mm (MNHN-Na 16087). — Stn CP 20, 05°15’S, 132°59’E, 769-809 m, 25.X.1991, 5 ♂♂ 5.2-7.4 mm, 25 ♀♀ 6.6-8.6 mm (MNHN-Na 16088) GoogleMaps ; 1 ♂ 7.3 mm (infested by bopyrid) (MNHN-Na). — Stn CC 21 , 05°14’S, 133°00’E, 688-694 m, 25.X.1991, 2 ♂♂ 6.0, 7.0 mm, 3 ♀♀ 7.6-10.6 mm (MNHN-Na 16089). — Stn CP 35, 06°08’S, 132°45’E, 390-502 m, 27.X.1991, 1♀ 7.4 mm (MNHN-Na 16090). — Tanimbar Islands, stn CC 57 , 08°19’S, 131°53’E, 603-620 m, 31.X.1991, 5 ♂♂ 6.3-6.7 mm, 10 ♀♀ 7.1-8.4 mm (MNHN-Na 16091) GoogleMaps ; same data, 1 ♀ 7.5 mm, infested by bopyrid (MNHN- Na). — Stn CP 38, 07°40’S, 132°27’E, 620-666 m, 28.X.1991, 3 ♂♂ 6.1-6.5 mm, 10 ♀♀ 3.6-8.2 mm (MNHN-Na 16092). — Stn CP 59, 08°20’S, 132°11’E, 405- 399 m, 31.X.1991, 1 ♀ 8.4 mm (MNHN-Na 16093). — Stn CP 69, 08°42’S, 131°53’E, 356-368 m, 2.XI.1991, 2 ♀♀ 7.8, 8.2 mm (MNHN-Na 16094). — Stn CP 71, 08°38’S, 131°44’E, 477-480 m, 2.XI.1991, 2 ♀♀ 8.4, 9.2 mm (MNHN-Na 19095) GoogleMaps .

New Caledonia. MUSORSTOM 4, stn 242, 22°05.8’S, 167°10.3’E, 500-550 m, 3.X.1985, 2 ♀♀ 4.6, 5.6 mm (MNHN-Na 16096).

BIOCAL, stn CP 75, 22°19’S, 167°23’E, 825-860 m, 4.IX.1985, 3 ♀♀ 5.3, 6.0 mm (largest specimen damaged) (MNHN-Na 16103).

BATHUS 1, stn CP 663, 20°58.66’S, 165°38.27’E, 730-780 m, 13.III.1993, 1 ♀ 8.5 mm (MNHN-Na 16104). — Stn CP 709, 21°41.78’S, 166°37.88’E, 650-800 m, 19.III.1993, 1 ♀ 6.6 mm (MNHN-Na 16105); 1 ♀ 6.6 mm, infested by bopyrid (MNHN- Na). — Stn CP 765, 22°09.6’S, 166°02.8’E, 600-630 m, 17.III.1993, 2 ♀♀ 8.0, 8.2 mm (MNHN-Na).

BATHUS 2, stn CP 743, 22°35.6’S, 166°26.2’E, 713-950 m, 14. V.1993, 1 ♀ 8.0 mm (MNHN-Na 16106). — Stn CP 765, 22°09.6’S, 166°02.8’E, 600-630 m, 17. V.1993, 2 ♀♀ 8.0, 8.1 mm (MNHN- Na 16107). — Stn CP 771, 22°09.52’S, 166°01.75’E, 610-800 m, 18. V.1993, 1 ♀ 7.0 mm (MNHN-Na 16108).

HALIPRO 1, stn CP 866, 21°26.91’S, 166°17.23’E, 550-600 m, 22.III.1994, 1 ♀ 7.0 mm (MNHN-Na 16111).

BATHUS 4, stn CP 913, 18°56.23’S, 163°04.86’E, 777-820 m, 5.VIII.1994, 1 ♀ 7.5 mm (MNHN-Na 16109). — Stn CP 950, 20°31.93’S, 164°56.11’E, 705-750 m, 10.VIII.1994, 4 ovig. ♀♀ 8.0- 8.4 mm (MNHN-Na 16110).

Loyalty Islands. MUSORSTOM 6, stn CP 438, 20°23.00’S, 166°29.10’E, 780 m, 18.II.1989, 1 ♀ 8.0 mm (MNHN-Na 16102).

Chesterfield Islands. MUSORSTOM 5, stn 323, 21°18.52’S, 157°57.62’E, 970 m, 14.X.1986, 1 ♀ 12.8 mm (MNHN-Na 16097). — Stn CC 384, 19°42.40’S, 158°50.80’E, 772- 756 m, 21.X.1986, 1 ♀ 7.7 mm (MNHN-Na 16098).— Stn CP 386, 20°56.21’S, 160°51.12’E, 770- 755 m, 22.X.1986, 1 ♂ 6.7 mm, 2 ♀♀ 5.4, 6.2 mm (MNHN-Na 16099). — Stn CP 387, 20°53.41’S, 160°52.14’E, 650-660 m, 22.X.1986, 1 ♂ 5.0 mm, 1 ♀ 7.0 mm, 1 juvenile 4.1 mm (MNHN-Na 16100). — Stn CC 390, 21°00.90’S, 160°50.30’E, 745-825 m, 22.X.1985, 1 ♀ 7.0 mm (MNHN-Na 16101).

Vanuatu. MUSORSTOM 8, stn CP 992, 18°52.34’S, 168°55.16’E, 775- 748 m, 24.IX.1994, 1 ♀ 6.5 mm, 1 ovig. ♀♀ 8.4 mm (MNHN-Na 16112). — Stn CP 993, 18°48.78’S, 168°54.04’E, 780-783 m, 24.IX.1994, 3 ♀♀ 6.2-7.6 mm (MNHN-Na 16113). — Stn CP 994, 18°47.72’S, 168°56.17’E, 649- 641 m, 24.IX.1994, 1 ♀ 8.2 mm (MNHN-Na 16114). — Stn CC 996, 18°52.41’S, 168°55.73’E, 764-786 m, 24.IX.1994, 1 ♀ 10.2 mm (MNHN-Na 16115). — Stn CP 1028, 17°54.01’S, 168°40.42’S, 624-668 m, 20.IX.1994, 2 ovig. ♀♀ 7.0, 8.0 mm (MNHN-Na 16116). — Stn CP 1035, 17°56.02’S, 168°44.06’E, 765-780 m, 29.IX.1994, 1 ovig. ♀ 9.3 mm (MNHN-Na 16117). — Stn CP 1055, 16°30.11’S, 167°55.13’E, 572-580 m, 1.X.1994, 3 ♀♀ 6.6-7.2 mm, 3 ovig. ♀♀ 8.2-8.6 mm (MNHN-Na 16118).

Tonga. BORDAU 2, stn CP 1556, 20°11’S, 174°45’W, 589-591 m, 7.VI.2000, 1 ♀ 7.3 mm (MNHN-Na 16119). — Stn CP 1565, NW of Tongatapu, 20°58’S, 175°16’W, 869-880 m, 9.VI.2000, 2 ♀♀ 5.8, 7.3 mm (MNHN-Na 16120) GoogleMaps ; 2 ovig. ♀♀ 10.6, 11.1 mm (MNHN- Na 16121); 1 ♀ 11.2 mm (photographed) (MNHN-Na 16122). — Stn CP 1640, 21°09’S, 175°24’W, 564-569 m, 21.VII.2000, 1 ♀ 7.2 mm (MNHN-Na 16123).

Solomon Islands. SALOMON 1, stn CP 1749, 09°20.9’S, 159°56.2’E, 582-594 m, 25.IX.2001, 1 ♀ 7.6 mm (MNHN-Na 16124). — Stn CP 1783, 08°32.8’S, 160°41.7’E, 399-700 m, 29.IX.2001, 2♀♀ 7.2, 7.6 mm (MNHN-Na 16125). — Stn DW 1772, 08°15.8’S, 160°40.4’E, 570-756 m, 28.IX.2001, 1 ♀ 9.6 mm (MNHN-Na 16126). — Stn CP 1794, 09°16.1’S, 160°07.7’E, 494-504 m, 30.IX.2001, 1 ♀ 7.2 mm (MNHN-Na 16127). — Stn CP 1806, 09°37.9’S, 160°49.7’E, 621-708 m, 2.X.2001, 1♀ 8.0 mm (MNHN- Na 16128). — Stn CP 1808, 09°45.5’S, 160°52.5’E, 611-636 m, 2.X.2001, 1 ♀ 7.2 mm (MNHN-Na 16129). — Stn 1859, 09°32.6’S, 160°37.3’E, 283-305 m, 7.X.2001, 1 ♀ 7.5 mm (MNHN-Na 16130).

SALOMON 2, SW Russel Island, stn CP 2175, 09°05.8’S, 158°59.9’E, 579-585 m, 21.X.2004, 3 ♀♀ 8.8-9.3 mm (MNHN-Na 16131). — Stn CP 2176, 09°09.4’S, 158°59.2’E, 600-875 m, 21.X.2004, 2 ♀♀ 7.6, 8.3 mm (MNHN-Na 16132). — Off St Isabel Island, stn CP 2182, 08°47.0’S, 159°37.9’E, 762-1060 m, 22.X.2004, 1 ♂ 4.2 mm (MNHN-Na 16133). — Stn CP 2184, 08°16.9’S, 159°59.7’E, 464-523 m, 23.X.2004, 2 ♀♀ 7.9, 9.4 mm (MNHN- Na 16134). — Stn CP 2186, 08°17’S, 160°00.0’E, 487-541 m, 23.XI.2004, 1 ovig. ♀ 10.0 mm (MNHN- Na 16135). — Stn CP 2187, 08°17.5’S, 159°59.8’E, 482-604 m, 23.X.2004, 1 ♂ 7.3 mm, 2 ♀♀ 9.1, 9.8 mm (MNHN-Na 16136). — Stn CP 2188, 08°17.9’S, 160°01.3’E, 495-677 m, 23.X.2004, 6 ♀♀ 8.1-11.8 mm (MNHN-Na 16137). — Stn CP 2189, 08°19.6’S, 160°01.9’E, 660-854 m, 23.X.2004, 5 ♀♀ 7.7-9.8 mm (MNHN-Na 16138). — Stn CP 2206, 07°43.4’, 158°29.0’E, 391-623 m, 25.X.2004, 1 ♀ 7.4 mm, 1 ovig. ♀ 10.0 mm (MNHN-Na 16139). — Off Choiseul Island, stn CP 2213, 07°38.7’S, 157°42.9’E, 495-650 m, 26.X.2004, 1 ♀ 9.2 mm (MNHN-Na 16140). — Off New Georgia Island, stn CP 2220, 632 m, 27.X.2004, 2 ♂♂ 5.7, 7.0 mm (MNHN-Na 16141). — Off Choiseul Island, stn CP 2226, 06°39.0’S, 156°14.3’E, 490-520 m, 28.X.2004, 1 ♂ 6.7 mm (MNHN-Na 16142). — Stn CP 2227, 06°37.2’S, 156°12.7’E, 508-522 m, 28.X.2004, 1 ♀ 8.2 mm (MNHN-Na 16143). — Stn CP 2228, 06°34.7’S, 156°10.5’E, 609-625 m, 28.X.2004, 4 ♀♀ 8.4-10.0 mm, 1 ovig. ♀ 8.3 mm ( CBM-ZC 8603). — Off Vella Lavella Island, stn CP 2244, 07°45.0’S, 156°26.7’E, 554-586 m, 1.XI.2004, 6 ♀♀ 7.9-10.9 mm, 7 ovig. ♀♀ 8.0- 11.3 mm (MNHN- Na 16144). — Stn CP 2245, 07°43.1’S, 156°26.0’E, 582-609 m, 1.XI.2004, 1 ♀ 9.7 mm, 3 ovig. ♀♀ 7.9-11.2 mm (MNHN-Na 16145). — Stn CP 2246, 07°42.6’S, 156°24.6’E, 664-682 m, 1.XI.2004, 2 ♀♀ 7.5, 10.1 mm, 2 ovig. ♀♀ 7.7, 10.6 mm (MNHN- Na 16146). — Stn CP 2247, 07°44.9’S, 156°24.7’E, 686-690 m, 1.XI.2004, 3 ♀♀ 7.5-9.0 mm (one infested by bopyrid) (MNHN-Na 16147). — Stn CP 2248, 07°42.5’S, 156°24.8’E, 650-673 m, 1.XI.2004, 2 ♀♀ 8.2, 10.4 mm (MNHN-Na 16148). — Vella Gulf, stn CP 2262, 07°56.4’S, 156°51.2’E, 460-487 m, 3.XI.2004, 2 ovig. ♀♀ 8.2, 8.9 mm (MNHN-Na 16149). — Off Tetepare Island, stn CP 2291, 08°39.2’S, 157°26.6’E, 408-470 m, 7.XI.2004, 1 ♀ 7.1 mm (MNHN-Na 16150). — Off Gatokae Island, stn CP 2297, 09°08.8’S, 158°16.0’E, 728-777 m, 8.XI.2004, 1 ovig. ♀ 9.1 mm (MNHN-Na 16151).

Polynesia (Austral Islands). BENTHAUS. Marotiri Island, stn DW 1881, 27°54.6’S, 143°28.5’W, 112-121 m, 6.XI.2002, 1 ♀ 6.5 mm (MNHN-Na 16152). — E of Rapa Island, stn DW 1889, 27°36.8’N, 144°15.7’W, 600-620 m, 7.XI.2002, 2 ♀♀ 4.6 mm, 6.1 mm (larger one photographed) (MNHN-Na 16153). — Stn CP 1891, 27°37.1’S, 144°15.4’E, 800-850 m, 7.XI.2002, 4 ♀♀ (not measured) (MNHN-Na 16154). — Stn CP 1892, 27°38.8’S, 144°15.6’W, 742-1000 m, 7.XI.2002, 1 ♀ 5.7 mm (MNHN-Na 16155). — Tubuai Islands, stn DW 1955, 23°18.6’S, 149°25.7’W, 750-850 m, 18.XI.2002, 3♀♀ 5.8-6.1 mm (MNHN-Na 16156). — Stn CP 1965, 23°21.3’S, 149°33.9’W, 19.XI.2002, 1 ♂ 4.9 mm, 8 ♀♀ 4.8-7.5 mm, 1 juvenile 3.2 mm (MNHN- Na 16157). — Stn CP 1967, 23°21.4’S, 149°34.2’W, 600-1200 m, 19.XI.2002, 10 ♂♂ 4.6-6.4 mm, 13 ♀♀ 4.4-7.0 mm (MNHN-Na 16158).

New Zealand. RV Tangaroa , stn 0413/127, 37°19.51’S, 177°05.42’E, 638- 542 m, 14.XI.2004, 1 ♀ 8.3 mm ( NIWA 13713).

DISTRIBUTION. — Widely distributed in the tropical to subtropical regions in the Indo-West Pacific: Zanzibar, Maldives, southern Japan,Taiwan, Philippines, Indonesia, Solomon Islands, New Caledonia, Vanuatu, Tonga, Austral Islands in French Polynesia ( Fig. 35 View FIG ); 112-970 m, but abundant at depths of 500-800 m.

DESCRIPTION

Rostrum ( Fig. 5 View FIG A-D) narrow triangular in dorsal view, 0.18-0.23 of carapace length, directed forward or slightly upward, straight, usually reaching or slightly overreaching distal margins of corneas; dorsal surface concave in proximal half; lateral margins usually armed with 2 pairs of small teeth, anterior pair usually arising from midlength of rostrum. Carapace ( Fig. 5 View FIG A-D) 1.60-1.80 times as long as wide; anterior epigastric tooth absent or greatly reduced to minute denticle or tubercle; posterior epigastric and cardiac teeth moderately small, cardiac tooth arising from two-thirds of carapace length; postorbital tooth showing as minute tubercle; epibranchial ridge weak, occasionally obsolescent; branchiostegal tooth moderately long, usually falling short of dorsodistal margin of antennal basicerite.

Third pleonal somite ( Fig. 5E View FIG ) with moderately convex tergum and moderately produced posterodorsal margin; fifth somite ( Fig. 5E, F View FIG ) rounded dorsally; sixth somite ( Fig. 5E, F View FIG ) 3.50-3.70 times longer than wide, 2.30-2.90 times longer than deep; dorsal surface rounded or faintly sulcate medially.

Eye ( Fig. 5A, D, G View FIG ) generally bean-shaped; cornea darkly pigmented (general colour gray to black), maximal diameter 0.18-0.21 of carapace length; corneal surface distinctly faceted with moderately large lenses ( Fig. 20C View FIG ); boundary between cornea and eye-stalk clearly delineated; eye-stalk only slightly constricted near base; papilla-like projection small. Antennular peduncle ( Fig. 5A View FIG ) falling short of midlength of antennal scale. Antennal scale ( Fig. 5A View FIG ) 0.60-0.75 of carapace length; lateral margin slightly concave or nearly straight, distolateral tooth slightly falling short of or nearly reaching distal margin of lamella. Palm of first pereopod ( Fig. 5H View FIG ) 3.80-4.30 times longer than wide; cutting edge strongly oblique; pollex small, width including tip of pollex 1.20-1.25 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. 5I View FIG ) overreaching distal margin of antennal scale by half to full length of dactylus; dactylus subspatulate, 0.60-0.70 of propodal length; carpus 0.70-0.80 of propodal length. Fifth pereopod ( Fig. 5J View FIG ) similar to fourth, slightly falling short of distal margin of antennal scale. Appendix masculina 0.50-0.70 length of appendix interna.

Coloration in life

Body and appendages generally light reddishbrown.

Size

Males CL 4.0- 7.4 mm; females CL 4.4-11.3 mm, ovigerous females CL 8.0- 11.3 mm.

REMARKS

The rostrum is usually armed with two pairs of lateral teeth, but either or both of the anterior pairs are rarely missing. The anterior epigastric tooth is minute or completely reduced.

During this study, two very similar but distinct forms were recognized in the material from the western Pacific. These two forms, having distinctly faceted cornea in common, differ from each other in the colour of the cornea, the length of the rostrum, the size of the anterior epigastric tooth, and the overall body size. The first form is characterized by the darkly pigmented cornea, the greatly reduced anterior epigastric tooth, which is occasionally completely absent, and the relatively small body size (the largest specimen is 12.8 mm in CL; the ovigerous specimens are 6.4-11.3 mm in CL); the second form is characterized by the opaque or lightly pigmented cornea, the possession of tiny but conspicuous anterior epigastric tooth and the relatively large size (the largest specimen is 14.0 mm in CL; the ovigerous females are 9.8-13.0 mm). Furthermore, these two forms are bathymetrically separated for the most part, although their bathymetrical ranges partially overlap at depths of 700- 900 m. Literature survey showed that the two forms should correspond to Parapontophilus junceus described by Bate (1888) and Pontophilus occidentalis var. indica de Man, 1918 , of which the latter has been placed in the synonymy of Parapontophilus junceus (see Chace 1984).

As Chace (1984) remarked, Bate’s (1888: fig. 3) illustration of Parapontophilus junceus is considerably different from the extant holotype ( Fig. 6A View FIG ). The rostrum of the holotype is now partially damaged with a distal part broken off and the colour of the cornea is possibly faded away during about 130 years after capture. Nevertheless, the anterior epigastric tooth is minute; the reconstructed rostrum slightly overreaches the distal margins of the corneas. Therefore, the holotype of P. junceus well corresponds to the first form. Reexamination of the type series of Pontophilus occidentalis var. indica , consisting of 16 specimens from six different stations of the Siboga , has revealed that two forms, corresponding to those recognized in the other material, are included. Chace (1984) seems to believe that one of the six specimens from the Siboga station 316 in the Bali Sea represented a name-bearing type of de Man’s taxon, as he suggested that the type locality of it is restricted to the Siboga station 316 in the Bali Sea. However, de Man (1918, 1920) did not designate a holotype for his taxon, or nobody has selected a lectotype for it. Therefore, the type series of P. occidentalis var. indica should be syntypes. In the interest of nomenclatural stability, I selected the ovigerous female (9.0 mm) from the Siboga station 316 in the Bali Sea as a lectotype of Pontophilus occidentalis var. indica , because de Man (1920) stated that “The 6 females from Stat. 316 are considered as the typical representatives of this new variety indica .” This lectotype ( Fig. 6B View FIG ) agrees quite well with the holotype of Parapontophilus junceus in every diagnostic aspect. Therefore, de Man’s taxon becomes a junior subjective synonym of P. junceus . Thus the second form is described as a new species, P. difficilis n. sp., in this study. Specimens from the other five Siboga stations (45, 88, 178, 211 and 300) are all referred to P. difficilis n. sp. In fact, de Man (1920) reported for these specimens that the colour of the eye was light, though coloration and pattern were reportedly variable, and that the anterior epigastric tooth is usually conspicuous.

Calman (1939) identified specimens from the western Indian Ocean collected during John Murray Expedition with Pontophilus indicus , although the depth range of the sampling sites was very wide: 494-2926 m. As mentioned before, specimens from depths greater than 2000 m (stn 26, 2312 m; stn 185, 2000 m; sn 120, 2926 m; stn 155, 2249 m; and stn 162, 1829- 2051 m) are most probable P. abyssi . Calman clearly stated that “In some the anterior gastric spine of the carapace is distinct although small (as in de Man’s fig. 63e), while in others it is represented by a microscopic granule (with a still smaller one immediately behind it)”, and therefore at least a part of specimens, collected from shallower depths (stn 109, 640 m; stn 115, 640- 659 m; and stn 145, 494 m) could be referred to Parapontophilus junceus . This assumption is supported by Calman’s statement that “all the specimens from 494 to 658 m have the eyes uniformly pigmented”. Other specimens from two stations (stn 34, 1022 m; and stn 193, 1061- 1080 m) might represent P. difficilis n. sp., although it needs to be verified.

The specimens identified by Kensley (1968, 1972) with Pontophilus occidentalis var. indica were not available during this study. However, Kensley (1968) clearly mentioned the presence of conspicuous anterior epigastric tooth on the carapace. Furthermore, his specimens came from abyssal depths of 2525-3148 m. The occurrence of Parapontophilus abyssi in the western Indian Ocean has been confirmed during this study, and therefore, Kensley’s (1968, 1972) records are referred to P. abyssi .

Chace (1984) reported Parapontophilus junceus from the Philippines and Indonesia (as Pontophilus gracilis junceus ). The illustrated male agrees rather well with P. difficilis n. sp. in the possession of two tiny but distinct anterior epigastric teeth. Considering the given bathymetrical range, there is little doubt that two species, P. junceus and P. difficilis , are actually represented in his material.

The records by Balss (1925) from the western Indian Ocean (as Pontophilus junceus ), Hanamura & Evans (1996) from Australia (as Parapontophilus gracilis junceus ), and Burukovsky (1990) from the Sala-y-Gomez and Nazka ridges in the southeastern Pacific ( Pontophilus junceus ) need to be verified. Therefore these references are questionably included in the synonymy.

Parapontophilus profundus ( Bate, 1888) ( Fig. 7 View FIG )

Pontophilus profundus Bate, 1888: 490 , pl. 88, fig. 1 (type locality: off Sydney, eastern Australia, 2600 fathoms). — Ortmann 1895: 186. — Zarenkov 1969: 80 (list).

Pontophilus gracilis profundus – Chace 1984: 47 (key), 51, fig. 19.

Parapontophilus gracilis profundus – Davie 2002: 240.

TYPE MATERIAL. — Holotype: Challenger, stn 165, off Sydney, Tasman Sea , 4755 m (?), juvenile, 3.1 mm ( BMNH 1888.22 ). Examined.

DISTRIBUTION. — Known only from the type locality in the Tasman Sea ( Fig. 35 View FIG ). The depth of the collecting site was recorded as 4755 m, but the record is questionable (see Remarks).

DESCRIPTION

Rostrum ( Fig. 7A, B View FIG ) slender in dorsal view, nearly spiniform, 0.32 of carapace length, directed forward, overreaching distal margins of corneas; dorsal surface slightly concave in basal 0.40; lateral margins armed with 2 small teeth in proximal 0.40. Carapace ( Fig. 7A, B View FIG ) about 1.60 times as long as wide; anterior epigastric tooth small, but conspicuous; posterior epigastric and cardiac teeth moderately small; postorbital tooth tiny, but acute; postorbital ridge inconspicuous; epibranchial ridge low, only reaching level of cardiac tooth; branchiostegal tooth reaching dorsodistal margin of antennal basicerite.

Third pleonal somite with moderately convex tergum and moderately produced posterodorsal margin; fifth somite rounded dorsally; sixth somite ( Fig. 7C View FIG ) 3.40 times longer than deep, with trace of median sulcus on dorsal surface.

Eye generally bean-shaped; cornea ( Fig. 7A, B View FIG ) entirely dark brown in preservative, maximal diameter 0.26 of carapace length; corneal surface distinctly faceted with relatively large lenses; boundary between cornea and eye-stalk clearly delineated; eyestalk only slightly constricted near base. Antennular peduncle ( Fig. 7A View FIG ) falling short of midlength of antennal scale. Antennal scale ( Fig. 7A View FIG ) about 0.80 of carapace length, 4.90 times longer than wide; lateral margin noticeably concave, distolateral tooth slightly falling short of distal margin of lamella.

Palm of first pereopod 3.90 times longer than wide; cutting edge moderately oblique; pollex relatively large, width of palm including tip of pollex about 1.40 of width proximal to base of pollex; merus with relatively weak dorsodistal tooth. Fourth and fifth pereopods broken; dactyli about 0.60 length of propodi.

Coloration in life

Unknown.

Size

This species is represented only by the juvenile holotype CL 3.1 mm.

REMARKS

The depth of the collecting site, where the holotype of P. profundus was taken, was indicated as 4755 m ( Bate 1888). However, the structure of the cornea of the holotype of P. profundus is very similar to that of other species inhabiting upper bathyal zone, i.e. P. gracilis and P. junceus . The cornea of these three species is darkly pigmented and its surface is distinctly faceted. On the other hand, in other species inhabiting abyssal zone comparable to that recorded for P. profundus , P. abyssi , P. cyrton n. sp., P. occidentalis , and P. talismani , the eye is opaque or light yellow, and the corneal surface is not faceted. Furthermore, Bate (1888) noted that the jar containing the holotype of P. profundus also included a detached second pereopod of a Lysmata species ( Hippolytidae ), of which almost all known species inhabit shallow to upper bathyal waters. These elements suggest that the depth record of the holotype of P. profundus is incorrect, and that the holotype actually came from shallower depth.

Parapontophilus profundus , represented only by the small holotype measuring 3.1 mm in the postorbital carapace length, is similar to P. gracilis , particularly in the very large eye. There is little doubt that the holotype is a juvenile. Nevertheless, comparison with small specimens of P. gracilis has revealed some minor but distinct differences. The rostrum is longer in P. profundus than in P. gracilis . It overreaches the corneas in P. profundus , rather than falling short of them in P. gracilis . The anterior epigastric tooth of P. profundus is small, but still conspicuous, while that of P. gracilis is greatly reduced in microscopic spinule or tubercle or completely absent. The lateral margin of the antennal scale is concave in both species, but the degree is stronger in P. profundus than in P. gracilis . The sixth pleonal somite is relatively slender in P. profundus than in P. gracilis (3.40 times as long as high versus 2.30-2.50 times as long). Because of these differences, I regard P. profundus as a distinct species.

In the original description, Bate (1888) mentioned that the posterodorsal margin of the third pleonal somite of the holotype was produced posteriorly and partially covered the fourth pleonal somite. However, reexamination of the holotype suggests that Bate (1888) misinterpreted the somewhat damaged abdomen as such.

Parapontophilus occidentalis ( Faxon, 1893) ( Figs 8 View FIG ; 20D View FIG )

Pontophilus occidentalis Faxon, 1893: 200 (type locality: the syntypes came from eight stations in the eastern Pacific: off Ecuador, 01°07.0’N, 80°21.0’W, 2831 m; Gulf of Panama, 02°34.0’N, 92°06.0’W, 2448 m; Gulf of Panama, 04°56.0’N, 80°52.30’W, 3243 m; Gulf of Panama, 05°43.0’N, 85°50.0’W, 1760 m; Gulf of Panama, 06°10.0’N, 83°06.0’W, 2648 m; Gulf of Panama, 06°21.0’N, 80°41.0’W, 3281 m; Gulf of Panama, 07°05.30’N, 79°40.0’W, 2286 m; off Costa Rica, 10°14.0’N, 96°28.0’W, 4018 m; off Guatemala, 14°46.0’N, 98°40.0’W, 3190 m); 1895: 131, pl. D, fig. 2-2d. — Ortmann 1895: 185. — Zarenkov 1976: 14, fig. 6. — Wicksten 1977: 963. — Retamal 1981: 105 (list). — Mèndez 1981: 121, fig. 351.

Pontophilus gracilis occidentalis – Chace 1984: 48 (key), fig. 23j. — Wicksten 1989: 305 (list), 313 (list). — Wicksten & Hendrickx 1992: 6 (list).

Not Pontophilus occidentalis – Kensley 1981: 28 (list) (= Parapontophilus abyssi ( Smith, 1884)) .

TYPE MATERIAL. — The following syntypes of Pontophilus occidentalis Faxon, 1893 , were examined: Albatross, stn 3381, Gulf of Panama, 04°56.0’N, 80°52.30’W, 3243 m, 6.III.1891, 4 ♀♀ 12.0- 17.6 mm ( MCZ 4583). — Stn 3382, Gulf of Panama, 06°21.0’N, 80°41.0’W, 3281 m, 7.III.1891, 5 ♀♀ 11.0-17.0 mm ( MCZ 4584).

In addition to the 2 lots above cited, the following specimens in 8 lots are considered to be syntypes of Pontophilus occidentalis: Albatross , stn 3361, Gulf of Panama, 06°10.0’N, 83°06.0’W, 2648 m, 25.II.1891, 2 specimens ( MCZ). — Stn 3363, Gulf of Panama, 05°43.0’N, 85°50.0’W, 1760 m, 27.II.1891, 2 specimens ( MCZ). — Stn 3392, Gulf of Panama, 07°05.30’N, 79°40.0’W, 2286 m, 10.III.1891, 1 specimen ( MCZ). — Stn 3398, off Ecuador, 01°07.0’N, 80°21.0’W, 2831 m, 23.III.1891, 2 specimens ( MCZ). — Stn 3413, Gulf of Panama, 02°34.0’N, 92°06.0’W, 2448 m, 5.IV.1891, 4 specimens ( MCZ). — Stn 3414, off Costa Rica, 10°14.0’N, 96°28.0’W, 4018 m, 8.IV.1891, 1 specimen ( MCZ). — Stn 3415, off Guatemala, 14°46.0’N, 98°40.0’W, 3190 m, 10.IV.1891, 2 specimens ( MCZ).

DISTRIBUTION. — Eastern Pacific, off San Cremente Island, California, to northern Chile ( Figs 34 View FIG ; 35 View FIG ), 1760-4018 m.

DESCRIPTION

Rostrum ( Fig. 8 View FIG A-D) moderately broad, triangular in dorsal view, 0.10-0.15 of carapace length, directed forward and slightly curved ventrally, far falling short of distal margins of corneas; dorsal surface shallowly concave in proximal half; lateral margins always armed with 2 pairs of small lateral teeth proximal to midlength. Carapace ( Fig. 8 View FIG A-D) about 1.70 times longer than wide; anterior epigastric tooth subequal to or slightly smaller than posterior epigastric tooth; posterior epigastric and cardiac teeth relatively small for genus; postorbital tooth small; postorbital and epibranchial ridges conspicuous; branchiostegal tooth relatively small, not reaching dorsodistal margin of antennal basicerite.

Third pleonal somite ( Fig. 8E View FIG ) with moderately convex tergum and moderately produced

B

posterodorsal margin; fifth somite with very low plateau bearing shallow median sulcus ( Fig. 8F View FIG ); sixth somite ( Fig. 8G, H View FIG ) 3.10-3.50 times longer than wide, 2.30-2.50 times longer than deep; dorsal surface with faint submedian ridges flanking very shallow median sulcus.

Eye ( Figs 8A, D View FIG ) rather subpyriform; cornea nonpigmented (colour generally opaque or light yellow in preservative), maximal diameter 0.15-0.17 of carapace length; corneal surface not faceted ( Fig. 20D View FIG ), but white granules possibly representing remnants of lenses visible through integument of cornea;boundary between corneal region and eye-stalk clearly delineated; eye-stalk only slightly constricted near base; papilla-like projection on mesial face small. Antennular peduncle ( Fig. 8A View FIG ) falling short of midlength of antennal scale.Antennal scale ( Fig. 8A View FIG ) 0.65-0.80 of carapace length, 4.00-4.50 times longer than wide; lateral margin slightly concave or nearly straight, distolateral tooth distinctly falling short of distal margin of lamella ( Fig. 8I View FIG ).

Palm of first pereopod ( Fig. 8J View FIG ) 3.90-4.20 longer than wide; cutting edge moderately oblique; pollex relatively large, width of palm including tip of pollex 1.45-1.94 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 and fifth pereopods broken in all specimens examined.

Coloration in life

Cephalothorax dark brown, otherwise reddishbrown; corneas opaque (according to the colour figure of Faxon [1895]).

Size

Males unavailable; females CL 11.0- 17.6 mm.

REMARKS

The rostrum constantly bears two pairs of lateral teeth in the specimens examined, but this consistency may only reflect the small number of the specimens.

This species appears close to the other two abyssal species, P.abyssi and P. talismani . Differences among the three species are discussed under the account of P. talismani . Pontophilus occidentalis var. indica de Man, 1918 is placed in the synonymy of Parapontophilus junceus (see Remarks of P. junceus ). Kensley (1981) listed Pontophilus occidentalis from southern African waters, but this merely reflects his previous identification of specimens from the region with Pontophilus occidentalis indica (cf. Kensley 1968). As discussed before, the southern African population having been referred to P.occidentalis or P.occidentalis indica is actually Parapontophilus abyssi .

MCZ

Museum of Comparative Zoology

USNM

Smithsonian Institution, National Museum of Natural History

RV

Collection of Leptospira Strains

VI

Mykotektet, National Veterinary Institute

V

Royal British Columbia Museum - Herbarium

CY

Centre des Yersinia

ZMA

Universiteit van Amsterdam, Zoologisch Museum

NTOU

Institute of Marine Biology, National Taiwan Ocean University

CC

CSIRO Canberra Rhizobium Collection

NIWA

National Institute of Water and Atmospheric Research

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Hippolytidae

Genus

Parapontophilus

Loc

Parapontophilus gracilis

Komai, Tomoyuki 2008
2008
Loc

Parapontophilus gracilis

DAVIE P. J. F. 2002: 239
2002
Loc

Parapontophilus gracilis profundus

DAVIE P. J. F. 2002: 240
2002
Loc

Pontophilus cf. abyssi

GARCIA RASO J. E. 1996: 736
1996
Loc

Parapontophilus gracilis junceus

DAVIE P. J. F. 2002: 240
HANAMURA Y. & EVANS D. R. 1996: 15
1996
Loc

Pontophilus gracilis abyssi

ALLEN J. A. & BUTLER T. H. 1994: 440
1994
Loc

Pontophilus gracilis junceus

BURUKOVSKY R. N. 1990: 209
1990
Loc

Pontophilus gracilis gracilis

CHACE F. A. JR 1984: 47
1984
Loc

Pontophilus gracilis abyssi

CHACE F. A. JR 1984: 47
1984
Loc

Pontophilus gracilis junceus

SAKAJI H. 2001: 211
TAKEDA M. & HANAMURA Y. 1994: 30
CHACE F. A. JR 1984: 47
1984
Loc

Pontophilus gracilis profundus

CHACE F. A. JR 1984: 47
1984
Loc

Pontophilus gracilis occidentalis

WICKSTEN M. K. & HENDRICKX M. 1992: 6
WICKSTEN M. K. 1989: 305
CHACE F. A. JR 1984: 48
1984
Loc

Pontophilus occidentalis

KENSLEY B. F. 1981: 28
1981
Loc

Pontophilus occidentalis

KENSLEY B. F. 1981: 28
1981
Loc

Pontophilus indicus

ZARENKOV N. A. 1969: 80
1969
Loc

Pontophilus occidentalis var. indica

KENSLEY B. F. 1968: 319
1968
Loc

Pontophilus occidentalis var. indica

KENSLEY B. F. 1968: 319
1968
Loc

Pontophilus challengeri

RICHARDSON J. R. & YALDWYN J. C. 1958: 41
1958
Loc

Pontophilus indicus

RICHARDSON J. R. & YALDWYN J. C. 1958: 41
1958
Loc

Pontophilus indica

CALMAN W. T. 1939: 219
1939
Loc

Pontophilus indicus

ZARENKOV N. A. 1969: 80
CALMAN W. T. 1939: 219
1939
Loc

Pontophilus junceus

BALSS H. 1925: 296
1925
Loc

Pontophilus occidentalis var. indica de Man, 1918: 161

MAN J. G. & DE 1918: 161
1918
Loc

Pontophilus gracilis

RATHBUN M. J. 1906: 910
1906
Loc

Pontophilus gracilis

BALSS H. 1925: 296
ALCOCK A. 1901: 115
ALCOCK A. 1899: 75
1899
Loc

Pontophilus challengeri

CROSNIER A. & FOREST J. 1973: 248
ZARENKOV N. A. 1969: 80
HOLTHUIS L. B. 1951: 16
KEMP S. 1911: 12
ORTMANN A. E. 1893: 49
1893
Loc

Pontophilus batei

FAXON W. 1893: 200
1893
Loc

Pontophilus occidentalis

RETAMAL M. 1981: 105
MENDEZ M. 1981: 121
WICKSTEN M. K. 1977: 963
ZARENKOV N. A. 1976: 14
ORTMANN A. E. 1895: 185
FAXON W. 1893: 200
1893
Loc

Pontophilus gracilis

BATE C. S. 1888: 487
1888
Loc

Pontophilus gracilis

BATE C. S. 1888: 487
1888
Loc

Pontophilus junceus

BATE C. S. 1888: 491
1888
Loc

Pontophilus profundus

ZARENKOV N. A. 1969: 80
ORTMANN A. E. 1895: 186
BATE C. S. 1888: 490
1888
Loc

Pontophilus abyssi

WILLIAMS A. B. & ABELE L. G. & FELDER D. L. & MANNING R. B. & MCLAUGHLIN P. A. & PEREZ FARFANTE I. 1989: 20
SAINT LAURENT M. & DE 1985: 47
SMITH S. I. 1884: 363
1884
Loc

Pontophilus gracilis

GARCIA RASO J. E. 1996: 736
DARDEAU M. R. & HEARD R. W. JR 1983: 24
TAKEDA M. & OKUTANI T. 1983: 72
MACPHERSON E. 1983: 66
CROSNIER A. & FOREST J. 1973: 242
KENSLEY B. F. 1972: 64
PEQUEGNAT W. E. & PEQUEGNAT L. H. & FIRTH R. W. & JAMES B. M. 1971: 10
PEQUEGNAT L. H. 1970: 113
CROSNIER A. & FOREST J. 1968: 1145
BARNARD K. H. 1950: 806
MAN J. G. & DE 1920: 260
KEMP S. 1916: 357
STEBBING T. R. R. 1905: 94
FAXON W. 1896: 157
ORTMANN A. E. 1895: 183
SMITH S. I. 1882: 36
1882