Pagurixus patiae Komai, 2006

Osawa, Masayuki & Komai, Tomoyuki, 2007, A new hermit crab species of the Pagurixus anceps group (Crustacea: Decapoda: Anomura: Paguridae) from southern Japan, and supplemental notes on P. patiae Komai, 2006, Zootaxa 1627, pp. 41-51 : 48-49

Pagurixus patiae Komai, 2006

( Figs. 4 , 5 C, D)

Pagurixus patiae Komai, 2006: 508 , figs. 1–4.

Material examined. 1 male (sl 1.5 mm), 1 female (sl 1.3 mm), Sunabe, Chatan, Okinawa Island, Ryukyu Islands, intertidal, near outer edge of reef flat, interspaces of branches of dead corals, coll. M. Osawa, 21 March 2007, CBM-ZC 9214; 4 males (sl 1.0– 1.5 mm), 2 ovigerous females (sl 1.1, 1.5 mm), same locality, 21 April 2007, CBM-ZC 9215.

Color in life ( Fig. 5 C, D). Shield, posterior carapace, ocular peduncles, and pereopods generally whitish. Shield and posterior carapace with scattered pink or red dots. Ocular peduncles each with 3 short brown markings on proximal and distal margins and mesial median portion of dorsal surface, and with brown line along lateral margin. Antennular peduncles translucent; ultimate segments each with broad brown ring subdistally and narrow brown ring subproximally; penultimate segments also each with subdistal brown ring. Antennal peduncles translucent, second to fourth segments and acicle with some small brown marks; fifth segments each with brown line along each lateral and mesial margin. Chelipeds with scattered pink and red dots; meri each with narrow brown ring on subdistal part; carpus of left cheliped tinged of brown color proximally on dorsal surface. Ambulatory legs with brown transverse bands; dactyli each with 1 proximal pale band; propodi each with 2 bands, subproximal band broader than median band; carpi each with 1 proximal band and 1 dorsal median spot; meri each with 1 subdistal and 1 median bands, each occasionally interrupted on lateral surface.

Habitat. Interspaces of branches of dead corals, near outer edge of intertidal reef flat; sympatric with two congeners, Pagurixus carinimanus and P. ruber .

Distribution. At present, known only from Okinawa Island and Iriomote Island, Ryukyu Islands, southwestern Japan.

Remarks. The newly collected specimens agree well with the type series of P. patiae except for some minor differences, which could be intraspecific variation. One male specimen (sl 1.4 mm; CBM-ZC 9215) has two small spines dorsally along the dorsomesial distal margin of the carpus of the right cheliped, but other males lack spines as in the type material. The palm of the left cheliped possesses a single row of small spines mesial to the dorsal midline in the newly obtained male specimens. The carpus of the left cheliped is also armed with two to four spines on the distal half of the dorsomesial margin. In the type specimens, those segments have a row of small tubercles, respectively. It is generally known that the armament of the male right cheliped is reduced with growth in Pagurixus species, and the better-developed armament of the right cheliped seems to reflect the young age of the present male specimens.

Pagurixus patiae was described on the basis of the male holotype, and five male and one ovigerous female paratypes. The right cheliped of the sole female known at that time is noted to be subequal in length to, and only slightly stouter than, the left cheliped. Komai (2006) considered that the right cheliped was probably in the process of regeneration because the right cheliped is larger than the left cheliped in the other known species of Pagurixus . As in the female paratype, however, the chelipeds of the three females are all subequal in size. Therefore, the subequal chelipeds seem to be normal for this species. Two small male specimens (sl 1.0, 1.0 mm; CBM-ZC 9215) also have chelipeds being subequal in length, but the right cheliped is slightly or distinctly stouter than the left cheliped.

Figures

FIGURE 4. Pagurixus patiae Komai, 2006. Male (sl 1.4 mm), CBM-ZC 9215. A, right cheliped, carpus, dorsal view; B, same, mesial view; C, left cheliped, carpus, dorsal view; D, same, mesial view. Scales equal 1.0 mm.

FIGURE 5. Fresh specimens, dorsal view. Pagurixus dissimilis n. sp. A, holotype, male (sl 1.6 mm), CBM-ZC 9068; B, paratype, ovig. female (sl 1.5 mm), CBM-ZC 9069. Pagurixus patiae Komai, 2006. C, male (sl 1.5 mm), CBM-ZC 9214; D, female (sl 1.3 mm), CBM-ZC 9214. Photographed by Y. Fujita (A, B) and M. Osawa (C, D).