Parapontophilus sibogae, 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 : 322-323

Parapontophilus sibogae n. sp.

( Figs 30 ; 31 ; 36 )

Pontophilus modumanuensis – De Man 1920: 270 (in part), pl. 21, fig. 64f-j. Not Pontophilus modumanuensis Rathbun, 1906 .

TYPE MATERIAL. — Holotype: Indonesia. Siboga , stn 89, Pulu Kaniungan Ketjil, 11 m, coral bottom, 21. VI.1899, ovig. ♀ 5.9 mm ( ZMA). Paratype: same data as holotype, 1 ovig. ♀ 5.9 mm ( ZMA).

ETYMOLOGY. — The specific name is derived from the research vessel name, Siboga .

DISTRIBUTION. — Known only from Pulu Kaniungan Ketjil, Celebes Sea ( Fig. 36 ), 11 m.

DESCRIPTION

Rostrum ( Fig. 30 A-C) narrow triangular in dorsal view, 0.14 of carapace length, directed forward, straight, falling short of distal margins of corneas; lateral margins armed with 2 pairs of small teeth, anterior pair arising distal to midlength of rostrum. Carapace ( Fig. 30A, B, D ) 1.30 times longer than wide; anterior epigastric tiny tooth, with minute accessory denticle; posterior epigastric tooth moderately small, supported by middorsal ridge reaching beyond midlength of carapace; cardiac tooth absent; postorbital tooth very small; epibranchial tooth absent; epibranchial ridge obsolete; branchiostegal tooth moderately large, reaching dorsodistal margin of antennal basicerite.

Third pleonal somite ( Fig. 30E ) with moderately convex tergum and with moderately produced posterodorsal margin. Fifth somite ( Fig. 30E, F ) rounded dorsally. Sixth somite ( Fig. 30E, F ) 2.30 times longer than wide, 2.00 times longer than deep, 2.30 length of fifth somite; dorsal surface rounded.

Eye ( Fig. 30A ) subpyriform; cornea light yellow in preservative; corneal surface distinctly faceted with moderately small lenses; maximal diameter of cornea 0.13 of carapace length; eye-stalk weakly constricted; mesial face without papilla-like projection. Antennular peduncle ( Fig. 30A ) reaching midlength of antennal scale. Antennal scale ( Fig. 30A, G ) 0.44-0.52 of carapace length and 2.50-2.60 times longer than wide; lateral margin straight, lamella strongly produced, distinctly overreaching distolateral tooth.

Palm of first pereopod ( Fig. 31A, B ) 3.30-3.50 times longer than wide; pollex moderately small, width of palm including tip of pollex about 1.20-1.30 of width proximal to base of pollex; cutting edge moderately oblique; merus with relatively weak dorsodistal tooth. Second pereopod slightly overreaching midlength of merus of first pereopod. Fourth pereopod ( Fig. 31C ) overreaching distal margin of antennal scale by half to full length of dactylus; dactylus elongate, subspatulate, 0.88-0.94 or propodal length; carpus about 0.60 of propodal length. Fifth pereopod ( Fig. 31D ) similar to fourth, slightly falling short of distal margin of antennal scale.

Male unknown.

Coloration in life

Unknown.

Size

Males unavailable; ovigerous females CL 5.9 mm.

REMARKS

As mentioned before, P.sibogae n. sp. appears closest to P.demani .Nevertheless, P.sibogae n.sp. is characteristic within the species group in having a proportionally shorter and broader antennal scale ( Table 2). Furthermore, P. sibogae n. sp. is distinguished from P. demani by the proportionally shorter rostrum, the smaller anterior epigastric tooth of the carapace (cf. Figs 30D and 22E ), the more strongly produced distal lamella of the antennal scale (cf. Figs 30G ; 22I ) and the proportionally longer dactylus of the fourth pereopod (cf. Figs 31C ; 23D ) ( Table 2).

The two type specimens were initially identified by de Man (1920) as Pontophilus modumanuensis . The bathymetrical record of this new species is exceptionally shallow for the genus, and it remains unclear that P. sibogae n. sp. is really an inhabitant of shallow water.

Figures

FIG. 30. — Parapontophilus sibogae n. sp., ovig. ♀ 5.9 mm, holotype, Pulu Kaniungan Ketjil, Indonesia (Siboga, stn 89) (ZMA): A, carapace and cephalic appendages, dorsal view; B, carapace, lateral view; C, rostrum dorsal view; D, anterior part of carapace, eye and basal part of antennae, lateral view; E, third to sixth pleonal somites, lateral view; F, fifth and sixth pleonal somites, dorsal view; G, left antennal scale, dorsal view. Scale bars: A, B, E, F, 2 mm; C, D, G, 1 mm.

FIG. 31. — Parapontophilus sibogae n. sp.: A, left first pereopod, lateral view; B, same, subchela, ventral view; C, dactylus, propodus and carpus of left fourth pereopod, lateral view;D, right fifth pereopod, lateral view;A, B, D, ovig.♀ 5.9 mm, holotype,Pulu Kaniungan Ketjil, Indonesia (Siboga, stn 89) (ZMA); C, ovig. ♀ 5.9 mm, paratype, same data as holotype (ZMA). 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. (✚).

FIG. 22. — Parapontophilus demani (Chace, 1984), ovig. ♀ 5.1 mm, holotype,Selat Roti, Lesser Sunda Islands,Indonesia (Siboga, stn 297) (ZMA): A, carapace and cephalic appendages, dorsal view (right antennal scale missing); B, carapace, lateral view; C, anterior part of carapace and eyes, dorsal view; D, rostrum, dorsal view; E, anterior part of carapace, cornea and basal part of antennae, lateral view;F, third to sixth pleonal somites,lateral view;G, fourth to sixth pleonal somites,dorsal view;H, left ophthalmic appendage, ventromesial view; I, left antennal scale, dorsal view. Scale bars: A-C, E-H, 1 mm; D, 0.5 mm.

FIG. 23.— Parapontophilus demani (Chace,1984):A, carapace and cephalic appendages,lateral view;B, left first pereopod,lateral view; C, same, subchela,ventral view; D, left fourth pereopod, lateral view;E, dactylus, propodus and carpus of fifth pereopod, lateral view; A, ♂ 4.2 mm, off Shionomisaki, Kii Peninsula, Japan (CBM-ZC 1203); B, C, ♀ 5.0 mm from same locality (CBM-ZC 3031); D, E, ovig. ♀ 5.1 mm, holotype, Selat Roti, Lesser Sunda Islands, Indonesia (Siboga, stn 297) (ZMA). Scale bars: 1 mm.