Polyonyx boucheti Osawa, 2007

Osawa, Masayuki, Naruse, Tohru & Ng, Peter K. L., 2018, New records of species of the Polyonyx sinensis group (Crustacea: Decapoda: Anomura: Porcellanidae) from Japan, the Philippines, Singapore, and Malaysia, with descriptions of two new species, Zootaxa 4429 (2), pp. 303-323 : 304-306

Polyonyx boucheti Osawa, 2007

( Figs. 1A , 2 )

Polyonyx boucheti Osawa, 2007: 39 , figs. 13–15 (type locality: Mepinyo, Santal Bay, Lifou Island, Loyalty Islands; Atelier LIFOU: sta. 1446, 20°50.8´S 167°09.7´E, 36–40 m).— Osawa & McLaughlin 2010: 114 (list).— Osawa & Poupin 2013: 1, figs. 1, 2.

Polyonyx aff. boucheti .—Poupin et al. 2013: 22, fig. 11D.

Material examined. Philippines. PANGLAO 2004 Marine Biodiversity Project: ZRC 2017.204 , 1 male (cl 1.5 mm) , 1 female (cl 1.7 mm), Alona Reef, Panglao Island , sta. B2, 9°33.0'N, 123°46.5'E, 5 m, reef slope, brushing, 31 May 2004 ; ZRC 2017.205 , 1 male (cl 1.6 mm), Doljo point, Panglao Island , sta. B12, 9°35.6'N, 123°43.2'E, 24– 27 m, reef slope, brushing, 14 June 2004 ; ZRC 2017.206 , 1 ovigerous female (cl 1.7 mm), Napaling, Panglao Island , sta. B21, 9°37.2'N, 123°46.4'E, 20–21 m, reef wall with small caves, brushing, 24 June 2004 ; ZRC 2017.207 , 1 male (cl 1.3 mm), Pontod Lagoon, Panglao Island , sta. B39, 9°32.8'N, 123°42.1'E, 17–25 m, reef wall with small caves, brushing, 3 July 2004 . Japan. Kume Island, Ryukyu Islands, KUMEJIMA 2009 Marine Biodiversity Expedition : RUMF-ZC-4735, 1 male (cl 1.7 mm), Madomari, fishing port, 2–3 m, on mooring rope, associated animal not recorded, coll. T. Komai, 21 November 2009 .

Coloration in life. Uncertain in the present specimens. The photographed specimen ( Fig. 1A ) may be a female from St. B2 of the PANGLAO 2004 Marine Biodiversity Project and it is very similar to an ovigerous female of P. boucheti from Mayotte shown by Osawa & Poupin (2013: fig. 2) in the fresh coloration.

Distribution. Known only from the Loyalty Islands in the southwestern Pacific and Comoro Islands in the southwestern Indian Ocean ( Osawa & Poupin 2013); now from the Philippines, and the Ryukyu Islands in the north hemisphere side of the western Pacific.

Habitat. Coral-sand, depths of 5–40 m ( Osawa & Poupin 2013). The present specimens were found on a mooring rope in a fishing port at the depth of 2–3 m or collected by brushing coral rubble from reef slopes or walls at the depths of 5– 27 m. Although all the known specimens of P. boucheti have not been recorded as commensal of any animals, the species probably lives symbiotically with a tube-dwelling polychaete as in many species of the P. sinensis group defined by Johnson (1958) (cf. Ng & Sasekumar 1993; Werding 2001; Osawa & Poupin 2013). The host polychaetes may be small-sized, non-chaetopterids that live in fragile tubes.

Remarks. The present specimens agree well with the descriptions of P. boucheti by Osawa (2007) and Osawa & Poupin (2013) in diagnostic aspects, except for the somewhat proportionally broader carpus of the cheliped ( Fig. 2C ) and comparatively stouter ambulatory legs, particularly the propodi ( Fig. 2E ).

Figures

FIGURE 1. Five Polyonyx species. Fresh specimens (A–D, G, H) and preserved specimens (E, F), entire animal, dorsal view. A, Polyonyx boucheti Osawa, 2007, probably female (cl 1.7 mm), Panglao Island, ZRC 2017.204; B, Polyonyx heok, ovigerous female (cl 7.6 mm), Iriomote Island, RUMF-ZC-4736; C, Polyonyx pilosibrachium n. sp., paratype, male (cl 3.1 mm), Iriomote Island, RUMF-ZC-4392; D, Polyonyx pilosibrachium n. sp., paratype, ovigerous female (cl 3.3 mm), Iriomote Island, RUMF- ZC-4389; E, Polyonyx sasekumari n. sp., paratype, male (cl 3.2 mm), Jeram, ZRC 2016.527; F, Polyonyx sasekumari n. sp., paratype, ovigerous female (cl 4.6 mm), Jeram, ZRC 2016.527; G, Polyonyx thai Werding, 2001, male (cl 2.8 mm), Johor Straits, St. DW131, ZRC 2017.202; H, Polyonyx thai Werding, 2001, ovigerous female (cl 3.5 mm), Johor Straits, St. DW131, ZRC 2017.202.

FIGURE 2. Polyonyx boucheti Osawa, 2007, male (cl 1.7 mm), RUMF-ZC-4735, Kume Island. A, carapace and ocular peduncles, dorsal view (setae drawn only on anterior part of rostrum); B, rostrum, dorso-anterior view; C, larger cheliped, merus and carpus, dorsal view (setae drawn only on dorso-anterior margin of carpus); D, larger cheliped, chela, dorsal perpendicular view (setae and surface structure not drawn); E, right second pereopod, lateral view (setae and surface structure not drawn). Scale bars = 1.0 mm.