Pagurixus acanthocarpus Komai & Okuno, 2009

Osawa, Masayuki, Kawai, Takashi & Sakamaki, Takashi, 2013, New records of Pagurixus Melin, 1939 (Crustacea: Decapoda: Paguridae) from the Ryukyu Islands, southwestern Japan, with description of a new species, Zootaxa 3669 (3), pp. 350-366 : 351

Pagurixus acanthocarpus Komai & Okuno, 2009

( Figs 1A, B , 3A )

[Japanese name: Konpeitou-himehonyadokari]

Pagurixus acanthocarpus Komai & Okuno, 2009: 146 , figs 5–8, 9C [type locality: Kashiwa-jima, Otsuki, Kochi Prefecture, southern Japan, subtidal].— McLaughlin et al. 2010: 31 (list).

Material examined. Tanega-shima, Osumi Group: stn Annou 1, 30°41.4´N, 131°04.5´E, 7 m, 16 Aug. 2012, coll. T . Kawai , 1 female (sl 1.5 mm), RUMF-ZC 2321 ; stn Kurosenohana 3, 30°40.4´N, 131°03.8´E, 7 m, 13–14 Aug. 2012, coll. T . Kawai , 1 male (sl 1.4 mm), 1 ovig. female (sl 1.8 mm), RUMF-ZC 2322 ; stn Sumiyoshi 1, 30°38.7´N, 130°56.5´E, 7 m, 4–8 Aug. 2012, coll. T . Kawai , 1 female (sl 2.1 mm), RUMF-ZC 2323 ; stn Sumiyoshi 2, 30°40.0´N, 130°56.3´E, 7 m, 4–8 Aug. 2012, coll. T . Kawai , 1 male (sl 1.8 mm), 1 ovig. female (sl 1.6 mm), RUMF-ZC 2324 . Yaku-shima, Osumi Group: stn Kurio 1-1, 30°13.9´N, 130°28.2´E, 7 m, 10 Aug. 2012, coll. T . Kawai , 1 male (sl 1.3 mm), RUMF-ZC 2325 ; stn Kurio 3-1, 30°16.4´N, 130°24.8´E, 7 m, 10 Aug. 2012, coll. T . Kawai , 1 male (sl 1.2 mm), RUMF-ZC 2326 . Amakusa, Kumamoto Prefecture, Kyushu main island: stn Ushibuka 1-1, 32°09.0´N, 129°58.5´E, 3 Dec. 2012, coll. T . Kawai , 1 male (sl 1.7 mm), RUMF-ZC 2327 .

Coloration in life. The color pattern of the present specimens agrees well with that of P. acanthocarpus described and illustrated by Komai & Okuno (2009, fig. 9C). See Fig. 1A, B .

Distribution. Previously known only from Kashiwa-jima in Kochi Prefecture and Izu-oshima in the Izu Islands, Japan; subtidal to 8 m ( Komai & Okuno 2009). Now also recorded from Tanega-shima and Yaku-shima, Osumi Group in the northern Ryukyus, and Amakusa in the western coast of Kyushu main island, Japan; 7 m.

Habitat. Rocky and coral reefs, on interspaces of rocks with algae and/or corals.

Remarks. The present specimens agree well with the original description of P. acanthocarpus in the diagnostic aspects. The dorsal margin of the carpus of each second pereopod is somewhat protuberant, and exclusive of a dorsodistal spine, the margin has one to five (usually one or two), tiny or moderately small spines in males and is unarmed or armed with one or two tiny spines in females. In males, the coxa of the right fifth pereopod ( Fig. 3A ) has a short but distinct, collar-like “posteromesial protrusion” (see Komai & Osawa 2006; Komai 2010), and the basal margin of its bearing prominent tuft of setae is more clearly demarcated than that of the holotype illustrated by Komai & Okuno (2009, fig. 5I). The fourth pereopods are subequal in size on right and left and in both males and females; the setation is similar on right and left in males, but in females, setae on the mesial surfaces of the dactylus, propodus, carpus, and merus are longer and more pronounced on the left side than on the right side.

Figures

FIGURE 1. Entire animal, dorsal view. A, Pagurixus acanthocarpus Komai & Okuno, 2009, male (sl 1.8 mm), stn Sumiyoshi 2, Tanega-shima, RUMF-ZC 2324; B, Pagurixus acanthocarpus Komai & Okuno, 2009, ovig. female (sl 1.6 mm), stn Sumiyoshi 2, Tanega-shima, RUMF-ZC 2324 (pleon missing); C, Pagurixus fasciatus Komai & Myorin, 2005, male (sl 1.7 mm), stn Sumiyoshi 2, Tanega-shima, RUMF-ZC 2331; D, Pagurixus fasciatus Komai & Myorin, 2005, female (sl 1.4 mm), stn Sumiyoshi 2, Tanega-shima, RUMF-ZC 2331 (right third pereopod and pleon missing); E, Pagurixus vicinus sp. nov., paratype, male (sl 1.4 mm), stn K 2-1, Kuchino-shima, RUMF-ZC 2346; F, Pagurixus vicinus sp. nov., paratype, ovig. female (sl 1.2 mm), stn K 2-1, Kuchino-shima, RUMF-ZC 2346.

FIGURE 3. Pagurixus acanthocarpus Komai & Okuno, 2009, male (sl 1.8 mm), stn Sumiyoshi 2, Tanega-shima, RUMF-ZC 2324 (A). Pagurixus fasciatus Komai & Myorin, 2005, male (sl 1.7 mm), stn Sumiyoshi 2, Tanega-shima, RUMF-ZC 2331 (B, C); female (sl 1.4 mm), same data, RUMF-ZC 2331 (D, E). Pagurixus formosus Komai, 2010, male (sl 2.7 mm), “KUMEJIMA 2009” stn Dive 28, Kume-jima, RUMF-ZC 2334 (F). A, coxa of right fifth pereopod, ventral view; B, D, right second pereopod, mesial view (setae omitted); C, E, left second pereopod, mesial view (setae omitted); F, left third pereopod, dactylus and propodus, lateral view (setae omitted). Scales: 0.5 mm.