Bull. Natl. Mus. Nat. Sci., Ser. A, Suppl. 3, pp. 137–156, March 22, 2009

Two New Species of the Hermit Genus Pagurixus (: Anomura: Paguridae) from the Western Pacific

Tomoyuki Komai1 and Junji Okuno2

1 Natural History Museum and Institute, Chiba, 955–2 Aoba-cho, Chuo-ku, Chiba, 260–8682 Japan e-mail: [email protected] 2 Coastal Branch of Natural History Museum and Institute, Chiba, 123 Yoshio, Katsuura, Chiba, 299–5242 Japan e-mail: [email protected]

Abstract Two new species of the pagurid hermit crab genus Pagurixus Melin, 1939 are described and illustrated. Pagurixus purpureus sp. nov., known from Japan and Papua New Guinea, is mor- phologically similar to P. boninensis (Melin, 1939), P. paulayi Komai and Osawa, 2006, and P. ruber Komai and Osawa, 2006. Pagurixus acanthocarpus sp. nov., so far restricted to Japanese wa- ters, appears close to P. fasciatus Komai and Myorin, 2005, P. handrecki Gunn and Morgan, 1992, P. nanus Komai and Takada, 2006, and P. dissimilis Osawa and Komai, 2007. Distinguishing char- acters between respective new species and their allies are discussed. Key words : Decapoda, Anomura, Paguridae, Pagurixus, new species, Japan, New Guinea.

The pagurid hermit crab genus Pagurixus scribed. The first, P. purpureus sp. nov., appears Melin, 1939 is widespread in tropical to warm closely related to P. boninensis (Melin, 1939), P. temperate waters in the Indo-Pacific regions. paulayi Komai and Osawa, 2006 and P. ruber Presently, 27 species are known in the genus Komai and Osawa, 2006, all referred to the P. (McLaughlin and Haig, 1984; Gunn and Morgan, boninensis species group (cf. Komai and Osawa, 1992; Morgan, 1993; Komai and Asakura, 1995; 2006). The second, P. acanthocarpus sp. nov., be- de Saint Laurent and McLaughlin, 2000; Komai longing to the P. anceps group (cf. Komai and and Myorin, 2005; Komai, 2006; Komai and Osawa, 2006), appears morphologically similar Osawa, 2006, 2007; Komai and Takada, 2006; to P. fasciatus Komai and Myorin, 2005, P. han- Osawa et al., 2006; Osawa and Komai, 2007), of drecki Gunn and Morgan, 1992, P. nanus Komai which 14 species have been described in the last and Takada, 2006, and P. dissimilis Osawa and eight years. Many of the known species inhabit Komai, 2007. Affinities of these two new species shallow sublittoral reefs where only divers are discussed in detail. Descriptions of the col- equipped with SCUBA are accessible. oration in life, which is known to be species spe- During ongoing studies on the sublittoral her- cific in the genus, are also provided for both mit crab fauna in Japan, conducted by us, a num- species. ber of undescribed species or poorly known The type specimens of the new species are de- species have been found, amongst them two un- posited in the National Museum of Nature and described species of Pagurixus. Furthermore, ex- Science, Tokyo (NSMT), the Natural History amination of abundant material from various Museum and Institute, Chiba (CBM), Coastal western Pacific localities, kindly made available Branch of Natural History Museum and Institute, for study by Dr. Gustav Paulay of the Florida Chiba, Katsuura (CMNH), and the Florida Muse- Museum of Natural History, University of Flori- um of Natural History, University of Florida, da, has resulted the finding of one of the two un- Gainesville (UF). The shield length, abbreviated described species also in Papua New Guinea. In as SL, is measured from the tip of rostrum to the the present paper the two new species are de- midpoint of posterior margin of the shield. Ter- 138 T. Komai and J. Okuno minology used in the description follows each with submarginal spinule. McLaughlin (2003), with the exceptions of num- Ocular peduncles (Fig. 1A) moderately long, bered thoracic sternites and pleon for abdomen. relatively slender, 0.60–0.70 length of shield, each with row of tufts of short setae on dorsal surface mesially; corneas slightly dilated, corneal width 0.26–0.38 of peduncular length; basal part Genus Pagurixus Melin, 1939 somewhat inflated, slightly broader than corneal Pagurixus boninensis species group width. Ocular acicles subtriangular or subovate, each with small submarginal spine distally. Pagurixus purpureus sp. nov. Antennular peduncles (Fig. 1A) overreaching [New Japanese name: Sumire-hime-hon-yadokari] distal corneal margins by 0.30–0.50 lengths of (Figs. 1–4; 9A, B) ultimate segments. Ultimate segment with tufts of long setae at dorsolateral distal angle; ventral Material examined. Holotype: NSMT-Cr surface with 2 longitudinal rows of setae, con- 19740, male (SL 3.4 mm), Issoh, Yakushima Is- sisting of mixture of short and long setae in distal land, Ohsumi Islands, 20 m, 11 January 2007, half (Fig. 1B). Basal segment with small lateral SCUBA diving, coll. Shigeru Harazaki. spine on statocyst lobe. Ventral flagellum with Paratypes: Japan. CMNH-ZC 2251, 1 female row of numerous long setae on lateral and mesial (SL 2.1 mm), Akino-hama, Izu-Oshima Island, margins. Izu Islands, 4 m, 15 May 2005, SCUBA diving, Antennal peduncles (Fig. 1A) overreaching coll. Hirohito Arima; CMNH-ZC 2252, 1 male distal corneal margins by 0.30 lengths of fifth (SL 2.1 mm), CMNH-ZC 2253, 1 female (SL segments. Second segment with tiny spinule at 2.3 mm), same locality, 4 m, 2 June 2005, SCUBA dorsomesial distal angle; laterodistal projection diving, coll. H. Arima; NSMT-Cr 19859, 1 fe- short, not reaching midlength of fourth segment, male (SL 2.3 mm), Kashiwa-jima Island, Ohtsu- terminating in simple or bifid spine. First seg- ki, Kochi Prefecture, 3 m, 10 June 2005, SCUBA ment with small laterodistal spine; ventromesial diving, coll. Naoki Nishimura; CBM-ZC 9560, 2 distal margin produced, unarmed or with spinule females (SL 2.0, 2.3 mm), same locality, subtidal, just lateral to antennal gland opening. Antennal SCUBA diving, coll. Eiji Myorin. Papua New acicle moderately long, arcuate, terminating in Guinea. UF 5398, 1 male (SL 2.4 mm), 4 oviger- slender spine, overreaching base of cornea but ous females (SL 1.7–2.1 mm), “Brooker Chan- not reaching distal corneal margin, mesial margin nel” in Calvados Channel, Milne Bay Province, with row of sparse stiff setae. Flagellum moder- Louisiade Archipalago, 11°03.09S, 152°28.62E, ately long, exceeding 4.00 length of shield. 5–10 m, 1 June 1998, coll. Gustav Paulay. Third maxilliped moderately stout; ischium Non-type. CMNH-ZC 1881, 1 young male (SL with well-developed crista dentata and 1 accesso- 1.2 mm), Akinohama, Izu-Oshima Island, Izu ry tooth. Islands, 13 m, 20 March 2005, SCUBA diving, Right cheliped of males (Figs. 2A, B, 3A) not coll. H. Arima. particularly elongate, moderately stout, distinctly Description. Shield (Fig. 1A) 1.00–1.15 times longer than left cheliped. Chela subovate in dor- longer than broad; anterior margin between ros- sal view, 1.80–2.10 times longer than broad. trum and lateral projections concave; anterolater- Dactylus distinctly shorter than palm; dorsome- al margins sloping; dorsal surface weakly con- sial margin not delimited; surfaces microscopi- vex, with few tufts of short setae laterally. Ros- cally finely granular; cutting edge with row of trum triangular, not reaching level of midlength small calcareous teeth in proximal 0.75 and row of ocular acicles, moderately broad, terminating of small corneous teeth in distal 0.25, terminat- acutely. Lateral projections slightly produced, ing in small corneous or calcareous claw. Palm Two new species of Pagurixus from the western Pacific 139

Fig. 1. Pagurixus purpureus sp. nov., holotype, male (SL 3.4mm), NSMT-Cr 19740. A, shield and cephalic ap- pendages, dorsal view; B, ultimate segment and ventral flagellum of left antennular peduncle, ventral view; C, left fourth pereopod, lateral view; D, right fourth pereopod, lateral view; E, sixth thoracic sternite, ventral view; F, coxae of fifth pereopods and eighth thoracic sternite, ventral view; G, telson, dorsal view. Scale bars: 1 mm for A; 0.5 mm for B–G. 140 T. Komai and J. Okuno

Fig. 2. Pagurixus purpureus sp. nov., holotype, male (SL 3.4mm), NSMT-Cr 19740. A, right cheliped, mesial view; B, same, lateral view; C, left cheliped, mesial view; D, same, lateral view. Scale bar: 1 mm. Two new species of Pagurixus from the western Pacific 141 slightly longer than carpus; convex dorsal surface gin faintly delimited by low of small, low gran- microscopically granular, with small but conspic- ules extending onto fixed finger. Cutting edge of uous spine at proximomesial angle; dorsolateral fixed finger with row of small blunt calcareous and dorsomesial margins not delimited; lateral, teeth in proximal 0.80 and row of small corneous mesial and ventral surfaces minutely granular or teeth in distal 0.20, terminating in small corneous nearly smooth, and occasionally with some tufts claw. Carpus 1.30–1.80 times longer than broad, of short setae on ventral surface. Cutting edge of subequal in length to merus; dorsal surface with fixed finger with row of tiny calcareous teeth and 2 rows of moderately large spines mesially and with 1 moderately large, blunt calcareous tooth with row of tiny tubercles laterally, dorsodistal proximal to midlength, terminating in small cal- margin with few small spines; lateral and mesial careous claw. Carpus 1.50–1.70 times longer surfaces coarsely granular, former nearly perpen- than broad; dorsal surface granular (granules dicular, without longitudinal ridge, latter with strongest mesially), with few small spines adja- several stiff setae directed mesially; ventrolateral cent to dorsodistal margin and with 2 rows of and ventromesial margins unarmed; ventral sur- moderately large spines mesially; dorsolateral face convex. Merus with row of very low protu- margin not delimited, unarmed; lateral, mesial berances on dorsal surface, dorsodistal margin and ventral surfaces also granular, lateral surface with several stiff setae; lateral surface with nu- without longitudinal median ridge, ventrolateral merous minute vertical ridges, ventrolateral mar- margin with row of minute granules; mesial face gin with 2–6 spines in distal one-third, otherwise with several short to long setae directed mesially, nearly smooth; ventromesial margin tuberculate ventromesial margin smooth, unarmed; ventral or granular, without conspicuous spine. Ischium surface moderately convex. Meral-carpal articu- with row of minute granules on ventromesial lation lacking any pronounced clockwise rota- margin, surfaces otherwise unarmed. tion; dorsal surface of merus with trace of trans- Left cheliped (Figs. 2C, D, 3B) moderately verse ridges and row of short setae, dorsodistal slender, morphologically similar between male margin with row of stiff setae; lateral face nearly and female. Chela 2.60–2.70 times longer than smooth in dorsal half and minutely granular in broad. Dactylus subequal in length to or slightly ventral half, ventrolateral margin with row of 5 longer than palm, with sparse tufts of setae on moderately small spines in distal 0.30; mesial surfaces (setae on ventral surface longest); cut- face smooth, with several stiff setae, ventrome- ting edge with row of small corneous teeth, ter- sial margin with row of 5 small spines; ventral minating in small corneous claw. Palm about half surface convex, with scattered granules and long length of carpus; dorsal surface slightly elevated setae. Ischium with smooth ventromesial margin; in midline and bearing scattered tiny tubercles or surfaces unarmed. granules, dorsolateral and dorsomesial margins Right cheliped of females (Fig. 3C–E) moder- not delimited; mesial surface with small granules ately stout for genus, slightly longer than or dorsally, smooth ventrally; ventral surface subequal in length to left cheliped. Chela 1.90– smooth, with some tufts of long stiff setae. Cut- 2.10 times longer than broad. Dactylus longer ting edge of fixed finger with row of small, slen- than palm; cutting edge with row of small, blunt der calcareous teeth in proximal 0.60–0.70 and calcareous teeth in proximal 0.60–0.70 and row row of small corneous teeth in distal 0.30–0.40, of small corneous teeth in distal 0.30–0.40, ter- terminating in small corneous claw. Carpus rela- minating in small corneous claw. Palm distinctly tively slender, slightly longer than chela or shorter than carpus; dorsal surface with scattered merus; length about 2.80 of distal width and minute granules and minute setae, and with 1 about 2.70 of greatest height; dorsal surface with conspicuous spine at proximomesial angle; dor- lateral row of 2–7 moderately small spines and somesial margin not delimited, dorsolateral mar- low protuberances, and with mesial row of 4–7 142 T. Komai and J. Okuno

Fig. 3. Pagurixus purpureus sp. nov., holotype, male (SL 3.4mm), NSMT-Cr 19740 (A, B); paratype, female (SL 2.0 mm), CBM-ZC 9560 (C–E). A, C, chela and carpus of right cheliped, dorsal view; B, left cheliped, dorsal view; D, right cheliped, lateral view; E, same, mesial view. Scale bars: 1 mm for A, B; 0.5 mm for C–E. Two new species of Pagurixus from the western Pacific 143 spines, dorsodistal margin unarmed or armed Fourth pereopods (Fig. 1C, D) slightly to with 1 small spine; lateral face steeply sloping, markedly unequal in both male and female. covered with coarse granules, without longitudi- Dactyli terminating in very small corneous nal median ridge, ventrolateral margin unarmed; claws, with numerous, dense long setae on dorsal mesial surface with granules dorsally and with margins (setae much longer and more numerous numerous short to long stiff setae directed in left than in right); left dactylus much broader mesially, ventromesial margin unarmed. Merus than right. Propodi with tuft of several setae on nearly smooth on dorsal surface, dorsodistal mar- mesial face at base of ventrodistal extremity; gin with stiff setae; lateral surface sparsely gran- propodal rasp consisting of single row of cor- ular, ventrolateral margin with 3–6 small spines neous scales; mesial faces nearly flat, with sever- in distal one-third to half; mesial surface nearly al long setae dorsally. Carpi each with tuft of smooth, with several stiff setae ventrally, ventro- setae on mesial face near ventrodistal angle lateral margin unarmed; ventral surface weakly (setae longer and more numerous in left than in convex, with few granules and long stiff setae. Is- right). chium with row of minute denticles on ventrome- Anterior lobe of sixth thoracic sternite (Fig. sial margin, otherwise unarmed. 1E) roundly subrectangular, anterior margin with Ambulatory legs (Fig. 4A, B) moderately long row of short to long setae. Eighth thoracic stern- and slender, generally similar from right to left in ite (Fig. 1F) composed of two unequal, rather both male and female. Dactyli (Fig. 4C, D) 0.84– widely separated, rounded lobes, each with nu- 0.92 (second) or 0.99–1.09 (third) length of merous short stiff setae. propodi, 5.30–6.20 times longer than high, termi- Males with coxae of fifth pereopods slightly nating in large corneous claws; dorsal surfaces unequal (Fig. 1F). Ventromesial protrusion origi- each with row of sparse stiff setae; lateral and nating from surface of right coxa well developed, mesial faces each with few tufts of short setae, clearly demarcated; setae arising from terminal mesial faces unarmed (second) or each armed margin of ventromesial protrusion, extending to with few corneous spinules adjacent to dorsal left coxa; left coxa with distinct gonopore partial- margin (third); ventral margins each with 6–10 ly obscured by short setae; numerous setae pre- relatively long corneous spines notably increas- sent along ventrolateral margin. Female with sin- ing in size distally. Propodi slightly tapering dis- gle left gonopore. tally, 3.90–4.10 (second) or 3.10–3.80 (third) Telson (Fig. 1G) with terminal margins slight- times longer than high; dorsal surfaces nearly ly oblique, bearing 4 or 5 prominent, slender smooth or with trace of low, transverse ridges, spines and several mesial spinules interspersed bearing tufts of short to moderately long stiff by spines; dorsal surface adjacent to terminal setae; lateral faces nearly smooth; ventral mar- margins slightly upturned, strongly calcified. gins each with row of 4–9 corneous spinules, Coloration in life. Shield translucent, with ventrodistal margins each with paired corneous yellowish-brown tint; posterior carapace also spines. Carpi each usually with small dorsodistal translucent. Ocular peduncles pale yellowish- spine, dorsal surface smooth, with row of tufts of brown, with tinge of purple. Ultimate segment of stiff setae; lateral faces nearly smooth. Meri near- antennular peduncle violet; penultimate and ly smooth on dorsal surfaces, each with single basal segments purplish. Antennal peduncle gen- setae or tufts of setae; lateral surfaces smooth; erally purple, fifth segment with distinct lateral ventrolateral distal margins each with small sub- and mesial stripes; flagellum alternated with pur- distal spine (second) or unarmed (third), ventral ple (5 or 6 articles) and white (1 or 2 articles). surfaces with few spinules at about distal 0.30 Right cheliped purplish-brown or reddish-brown; (second) or smooth (third), all with few short fingers whitish. Left cheliped generally purple, setae. distal part of fingers whitish. Ambulatory legs 144 T. Komai and J. Okuno

Fig. 4. Pagurixus purpureus sp. nov., holotype, male (SL 3.4mm), NSMT-Cr 19740. A, right second pereopod, lateral view; B, left third pereopod, lateral view; C, dactylus of right second pereopod, mesial view; D, dacty- lus of left third pereopod, mesial view. Scale bars: 1 mm for A, B; 0.5 mm for C, D. Two new species of Pagurixus from the western Pacific 145 striped with purple and white; dorsal and ventral surfaces of dactyli and propodi purple, lateral and mesial faces of these segments each with purple median stripe, otherwise white; meri each ish purple, with purple dorsal stripe extending onto mesial mesial surface distally and median stripe, ventral surface purple, and otherwise white. Pleon translucent. See Fig. 9A, B. ting of tufts short setae . Distribution. So far known from Japan (Izu Islands to Yakushima Island) and Papua New P. ruber P. Guinea; subtidal to 13 m. Remarks. Pagurixus purpureus sp. nov. be- and longs to the P. boninensis group because of the possession of two setal rows on the ventral sur- P. paulayi P. face of the ultimate segment of the antennular , peduncle. This informal species group includes the following 13 species: P. laevimanus (Ort-

mann, 1892), P. maorus (Nobili, 1906), P. boni- boninensis P. nensis (Melin, 1939), P. tweediei (Forest, 1956), P. festinus McLaughlin and Haig, 1984, P. nomu- sp. nov., sp. nov., rai Komai and Asakura, 1995, P. brachydactylus Komai and Osawa, 2006, P. carinimanus Komai and Osawa, 2006, P. concolor Komai and Osawa, P. purpureus P.

2006, P. paulayi Komai and Osawa, 2006, P. pse- , liophorus Komai and Osawa, 2006, P. pulcher Osawa, Fujita and Okuno, 2006, and P. ruber boninensisP. paulayi P. ruber P. Pagurixus

Komai and Osawa, 2006. Among them, P. boni- and white preservative distal ring with white nensis, P. paulayi and P. ruber are close to the new species in the lack of a longitudinal ridge on the lateral surface of the carpus of each cheliped and the relatively slender ambulatory dactyli.

Differences among the four species are summa- sp. nov. rized in Table 1. The new species appears unique in having two dorsomesial rows of relatively large spines on the carpus of the right cheliped. P. purpureus P. In P. boninensis and P. paulayi, there are one or two rows of small spines on the dorsomesial sur- face of the carpus of the right cheliped; and there is no dorsomesial row of spines in adults of P. Table 1. Comparison among four species of ruber, although a single small dorsomesial spine may be present in females. In the pattern of the ventral setal rows on the ultimate segment of the

antennular peduncle, the new species is similar to Items P. paulayi, but the non-spinulose palm of the right cheliped, the presence of one or more of antennular peduncleright cheliped and long setaeof right cheliped spines large moderately setae small spines and long setae small spines males protrusion; setal tuft long protrusion; setal tuft long protrusion; setal tuft long protrusion; setal tuft very short Setal rows of ultimate segment of ultimate segment Setal rows consisting of mixture short consisting of tufts short consisting of mixture short consis Dorsal surface of right palmDorsal surface of carpus of non-spinulose of merus margin Ventrolateral of with 2 mesial row with 2–6 small spines of right fifth pereopod Coxa with prominent ventromesial with prominent ventromesial of few with 1 mesial row with 1 or 2 subdistal spines non-spinulose with prominent ventromesial with 1 subdistal spine of with 1 or 2 mesial rows without ventro of spines non mesial row with 1 subdistal spine spinulose non-spinulose spines on the ventrolateral margin of the merus Left gonopore of malesColor of ambulatory legs present striped with purple and white striped with reddish brown light purple generally in red or redd generally present absent absent 146 T. Komai and J. Okuno of the right cheliped, and the possession of the SCUBA diving, coll. Hirohito Arima. left gonopore in males distinguish the new Description. Shield (Fig. 5A) 1.05–1.11 times species from P. paulayi. The new species is readi- as long as broad; anterior margin between ros- ly distinguished from P. ruber by the different trum and lateral projections concave; anterolater- pattern of the ventral setal rows on the ultimate al margins sloping; posterior margin roundly segment of the antennular peduncle, the presence truncate; dorsal surface naked. Rostrum triangu- of two to six spines on the ventrolateral margin lar, not reaching midlength of ocular acicles, of the merus of the left cheliped, and the posses- moderately broad, terminating acutely. Lateral sion of a well-developed ventromesial protrusion projections obtuse, each with submarginal spin- and tuft of long setae on the coxa of the right ule. fifth pereopod in males. From P. boninensis, P. Ocular peduncles (Fig. 5A) moderately stout, purpureus differs in the different pattern of the 0.60–0.70 length of shield, each with few tufts of ventral setal rows on the ultimate segment of the short setae on dorsomesial surface; middle part antennular peduncle, and more prominent setal slightly inflated, subequal to corneal width; tufts of the dactylus and carpus of the left fourth corneas slightly dilated, corneal width 0.30–0.36 pereopod. The living coloration of the new of peduncular length. Ocular acicles subtriangu- species is distinctive in the violet antennular pe- lar, each with submarginal spinule. duncle and the ambulatory legs longitudinally Antennular peduncles (Fig. 5A) overreaching striped with purple and white. Pagurixus boni- distal corneal margins by 0.20–0.40 lengths of nensis also has similarly striped ambulatory legs, ultimate segments. Ultimate segment with 1 but the base color is reddish brown; the antennu- short seta at dorsolateral distal angle; ventral sur- lar peduncle is also reddish brown. Chelipeds and face lacking longitudinal rows of setae. Basal ambulatory legs of P. ruber are almost entirely segment with small spine on distal margin of sta- purplish red occasionally with white distal rings tocyst lobe. Ventral flagellum with few short on the propodi of the ambulatory legs. Coloration setae on lateral and mesial margins. in life remains unknown in P. paulayi, although Antennal peduncles (Fig. 5A) slightly reaching the preservative color was described by Komai beyond distal corneal margins. Third segment and Osawa (2006). with small spine at distomesial angle. Second Etymology. Named in reference to the vivid segment with spinule at dorsomesial distal angle; purple color in life. laterodistal projection reaching midlength of fourth segment, terminating in simple spine. First Pagurixus anceps species group segment unarmed on lateral face; ventromesial distal margin strongly produced, but unarmed. Pagurixus acanthocarpus sp. nov. Antennal acicle arcuate, terminating in slender spine, overreaching base of cornea but not reach- [New Japanese name: Konpeitou-hime-hon-yadokari] ing distal margin; mesial margin with few stiff (Figs. 5–8; 9C) setae. Flagellum relatively short, about 2.5 times longer than shield. Material examined. Holotype: NSMT-Cr Third maxilliped moderately stout; ischium 19741, male (SL 1.5 mm), Kashiwa-jima Island, with well-developed crista dentata and 1 accesso- Ohtsuki, Kochi Prefecture, subtidal, 30 June ry tooth. 2005, SCUBA diving, coll. Eiji Myorin. Male right cheliped (Fig. 6A–C) large, not par- Paratypes: CBM-ZC 9517, 1 male (SL 1.6 ticularly elongate. Chela subovate in dorsal view, mm), same data as holotype; CMNH-ZC 1871, 1 about 1.60 times longer than broad. Dactylus female (SL 1.8 mm), Akino-hama, Izu-Oshima slightly shorter than palm, terminating in small Island, Izu Islands, 8 m, 26 December 2004, corneous claw; dorsomesial margin not delimit- Two new species of Pagurixus from the western Pacific 147

Fig. 5. Pagurixus acanthocarpus sp. nov., holotype, male (SL 1.5mm), NSMT-Cr 19741. A, shield and cephalic appendages, dorsal view; B, right second pereopod, lateral view; C, dactylus to carpus of right second pereo- pod, mesial view; D, left third pereopod, lateral view; E, dactylus to carpus of left third pereopod, mesial view; F, dactylus to carpus of left fourth pereopod, lateral view; G, same of right fourth pereopod, lateral view; H, sixth thoracic sternite, ventral view; I, coxae of fifth pereopods and eighth thoracic sternite, ventral view; J, telson, dorsal view. Scale bars: 0.5 mm. 148 T. Komai and J. Okuno

Fig. 6. Pagurixus acanthocarpus sp. nov., holotype, male (SL 1.5mm), NSMT-Cr 19741. A, chela and carpus of right cheliped, dorsal view; B, right cheliped, mesial view; C, same, lateral view; D, chela and carpus of left cheliped, dorsal view; E, left cheliped, mesial view; F, same, lateral view. Scale bar: 0.5 mm. Two new species of Pagurixus from the western Pacific 149 ed; dorsal and mesial surfaces with numerous weakly convex dorsal surface covered with small granules, latter with short oblique ridge coarse granules, row of larger, occasionally mul- proximally; cutting edge with 3 low calcareous tifid granules on midline, and short, distinct teeth in proximal 0.70 and row of small corneous granular ridge proximomesially; dorsolateral teeth in distal 0.30. Palm subequal in length to margin delimited by sharp, granular ridge ex- carpus; convex dorsal surface covered with small tending to tip of fixed finger; dorsomesial margin granules; dorsolateral margin distinctly delimited also delimited by sharp, faintly granular ridge; by tuberculate or granular ridge extending onto lateral surface with scattered low protuberances, fixed finger; dorsomesial margin also delimited mesial surface nearly smooth, and ventral surface by sharp, granular ridge; lateral surface with with few low protuberances and tufts of setae. scattered, coarse granules, mesial and ventral sur- Fixed finger terminating in small corneous claw; faces nearly smooth. Fixed finger terminating in cutting edge with row of small, subacute calcare- calcareous claw; cutting edge with row of low, ous teeth in proximal half and row of small cor- blunt calcareous teeth. Carpus nearly as long as neous teeth in distal half. Carpus slightly longer broad and subequal in length to merus; dorsal than broad and subequal in length to merus; dor- surface nearly smooth, but with some scattered sal surface with scattered small spines and gran- short spiniform setae, bearing 2 rows of small to ules laterally and with 2 rows of moderately large moderately large spines adjacent to dorsomesial spines mesially, dorsodistal margin with 3 small margin, dorsolateral surface rounded; dorsome- spines; lateral surface with scattered small, low sial margin weakly delimited by row of small protuberances, ventrolateral margin with few spines or spinulose tubercles occasionally bear- small granules; mesial surface with row of small ing spiniform setae; dorsodistal margin with row spines dorsally, but otherwise nearly smooth, of small tubercles or granules; lateral surface ventromesial margin granular in distal part; ven- nearly smooth, ventrodistal margin with subdistal tral surface strongly convex, naked. Meral-carpal spinule followed by row of low tubercles; mesial articulation lacking any pronounced clockwise surface with scattered granules distally, distal rotation; dorsal surface of merus with very low margin unarmed; ventral surface strongly convex, transverse ridges, dorsodistal margin with few naked. Meral-carpal articulation lacking any pro- short setae; lateral face with scattered granules, nounced clockwise rotation; dorsal surface of ventrolateral margin with row of small spines or merus smooth, dorsodistal margin with few short tubercles; mesial face smooth, convex ventrome- setae; lateral face smooth, ventrodistal margin sial margin nearly smooth; ventral surface also slightly tuberculate; mesial face smooth, convex smooth, with only few setae. Ischium with ventromesial margin smooth; ventral surface also smooth ventromesial margin; surfaces unarmed. smooth, with only few short setae. Ischium with Male left cheliped (Fig. 6D–F) moderately smooth ventromesial margin; surfaces unarmed. short and stout. Chela about 2.10 times longer Female right cheliped (Fig. 7A–C) moderately than wide, distinctly longer than carpus. Dactylus large, distinctly longer than left. Chela about 1.40 distinctly longer than palm, terminating in small times longer than broad, with markedly arched corneous claw; surfaces smooth, rounded dor- lateral margin. Dactylus longer than palm, termi- somesially, with scattered short setae; cutting nating in small corneous claw; dorsal surface edge with row of small corneous teeth. Palm with tuberculate median ridge extending beyond about half length of carpus; dorsal surface con- midlength; dorsomesial margin delimited by row vex, with 2 rows of small spines medially and of tiny tubercles or granules; mesial surface with scattered granules on dorsolateral face; trace of scattered tiny tubercles or granules proximally; delineation of lateral margin formed by low pro- cutting edge with row of small corneous teeth on tuberances; ventrolateral face with low protuber- distal 0.75. Palm distinctly shorter than carpus; ances; mesial surface with 3 low, short ridges 150 T. Komai and J. Okuno dorsally, otherwise nearly smooth; ventral sur- ing distally, about 4.20 times longer than high face weakly convex, with several tufts of moder- (second and right third) or 3.50 times (left third); ately long setae. Fixed finger terminating in small dorsal surfaces smooth, with sparse short setae; corneous claw, cutting edge with row of small lateral faces smooth; ventral margins each with 5 tiny calcareous teeth and interspersed with or 6 corneous spinules (spinules on left third minute corneous teeth. Carpus somewhat com- longer than those on other legs), ventrodistal pressed laterally, shorter than merus; length margins each with paired corneous spines. Carpi about 2.0 times distal width and 1.5 times height; each with small dorsodistal spine; dorsal surface dorsal surface with 3 lateral spines and 6 mesial of right second with 1 (paratype) or 5 (holotype) spines, dorsodistal margin with 1 spine medially; small spines, that of left second with 1 small lateral face nearly perpendicular, with scattered spine arising proximal to midlength, and those of granules and few spiniform setae dorsally, ven- third pereopods each with low, tiny protuber- trolateral margin with row of small spines; ances; row of sparse setae present on each dorsal mesial face dorsally with low protuberances surface; laterodistal margin of left third with row bearing spiniform setae, ventrodistal margin un- of stiff setae, those on other legs naked. Meri armed; ventral surface convex, with several long with smooth dorsal margins bearing sparse setae; setae. Merus smooth on dorsal surface, dorsodis- lateral surfaces nearly smooth; ventrolateral dis- tal margin unarmed; lateral surface with sparse tal margins each with small subdistal spine (sec- granules, ventrolateral margin with row of small ond pereopod) or unarmed (third), ventral sur- spines in distal half; mesial face smooth, ven- faces armed with few spinules (second pere- tromesial margin minutely tuberculate; ventral opods) or unarmed (third pereopods). surface weakly convex, smooth, with some long Female ambulatory legs (Fig. 8A–E) generally setae. Ischium with row of minute granules on stouter than those of males, third pereopods ap- ventromesial margin, otherwise unarmed. preciably dissimilar, left distinctly stouter than Female left cheliped generally similar to that right. Number of ventral spines on dactyli 7 in of male, but granulation and sculpture of chela second, 10 in right third, and 8 in left third. more pronounced. Chela (Fig. 7D–F) 1.70 times Propodi each with 4–7 ventral spines and 1 or 2 longer than wide with noticeably arched lateral ventrodistal spines. Carpus of left third pereopod margin. Dactylus with few granules proximodor- with row of stiff setae on laterodistal margin; sally. Dorsal surface of palm notably elevated dorsal surfaces without conspicuous spines ex- medially, with prominent, granular ridge mesial cept for dorsodistal spines, but with tiny, low to midline, and lower, but similarly granular protuberances in right second pereopod. ridge slightly lateral to midline, sloping dorsolat- Fourth pereopods (Fig. 5F, G) subequal and eral surface with scattered granules, dorsomesial similar on right and left. Dactyli moderately to mesial faces with sparse granules; lateral mar- broad, slightly curved, terminating in small cor- gin delimited by sharp, weakly granular ridge ex- neous claws; dorsal margins with few short setae. tending onto fixed finger as interrupted ridge. Propodi each with 1 tuft of setae on dorsal mar- Male ambulatory legs (Fig. 5B–E) moderately gins; mesial face nearly flat or slightly convex, slender, generally similar on right and left in sec- with few short setae; propodal rasp of single row ond, left third slightly stouter than right. Dactyli of corneous scales. Carpus without prominent 0.90–1.00 length of propodi, 5.30–6.20 times tufts of setae on mesial face. longer than high, terminating in large corneous Anterior lobe of sixth thoracic sternite (Fig. claws; dorsal surfaces each with few short setae; 5H) roundly subrectangular, with row of short to lateral and mesial faces smooth; ventral margins long setae on anterior margin. Eighth thoracic each with 8 or 9 long corneous spines increasing sternite (Fig. 5I) composed of 2 subequal, close- in size distally. Propodi weakly curved, not taper- ly-set, rounded lobes; ventral surface of each Two new species of Pagurixus from the western Pacific 151

Fig. 7. Pagurixus acanthocarpus sp. nov., paratype, female (SL 1.8mm), CMNH-ZC 1871. A, chela and carpus of right cheliped, dorsal view; B, right cheliped, mesial view; C, same, lateral view; D, chela of left cheliped, dorsal view; E, same, mesial view; F, same, lateral view. Scale bar: 0.5 mm. 152 T. Komai and J. Okuno

Fig. 8. Pagurixus acanthocarpus sp. nov., paratype, female (SL 1.8mm), CMNH-ZC 1871. A, right second pereopod, lateral view; B, dactylus to carpus of right second pereopod, mesial view; C, left third pereopod, lateral view; D, dactylus to carpus of left third pereopod, mesial view; E, right third pereopod, lateral view. Scale bars: 0.5 mm. Two new species of Pagurixus from the western Pacific 153

Fig. 9. Entire in dorsal view. A, Pagurixus purpureus sp. nov., holotype, male (SL 3.4mm), NSMT-Cr 19741, photo by J. Okuno; B, Pagurixus purpureus sp. nov., paratype, female (SL 2.3mm), NSMT-Cr 19859, photo by J. Okuno; C, Pagurixus acanthocarpus sp. nov., holotype, male (SL 1.5mm), NSMT-Cr 19741, photo by T. Komai. lobe flattened, naked. horizontal, bearing 4 (left) or 2 (right) spinules; Coxae of male fifth pereopods (Fig. 5I) slight- lateral margins of posterior lobes not calcified. ly unequal; weak ventromesial protrusion arising Coloration in life. Carapace translucent; from surface of right coxa, bearing prominent shield with tinge of brown posterior to base of tuft of setae arising at midlength and reaching to ocular peduncles and pair of brown spots lateral- left coxa. Left coxa with gonopore. Female with ly. Ocular peduncles translucent, with tinge of left gonopore. brown basally. Antennular peduncles with broad Telson (Fig. 5J) with terminal margins nearly brown band on penultimate segment; ultimate 154 T. Komai and J. Okuno segment generally brown, proximal and distal 2006, P. patiae Komai, 2006, P. nanus Komai and portions colorless; flagella yellowish brown. An- Takada, 2006, P. haigae Komai and Osawa, 2007 tennal peduncle generally translucent, second and P. dissimilis Osawa and Komai, 2007. The segment with tinge of brown basally; fifth seg- distinctly ridged dorsomesial margin of the right ment marginally brown; flagellum entirely light palm links the new species to P. fasciatus and P. brown. Right cheliped generally white, merus handrecki. In the other 12 species, the dorsome- with dark brown blotches dorsally. Left cheliped sial surface of the right palm is rounded or faint- also white, with dark brown transverse band on ly ridged. Differences among the three species merus. Ambulatory legs banded with white and are summarized in Table 2. The new species is dark brown; dactyli dark brown in proximal one- characteristic in having conspicuous spine(s) on third, becoming paler distally; propodi each with the dorsal surface of the carpus of the right sec- band occupying about proximal one-third; carpi ond pereopod in addition to a dorsodistal spine, with tinge of brown proximally; meri each with 2 at least in the male. In the other two species, the transverse bands subdistally and proximally; is- carpus of the second pereopod does not have chia each with brown patch laterally. See Fig. 9C. spines on the dorsal surface, except for the dor- Distribution. Kashiwa-jima Island, Ohtsuki, sodistal spine. With regard to the female, it is dif- Kochi Prefecture, and Izu-Oshima Island, Izu Is- ficult to fully assess intraspecific variation. Nev- lands; subtidal to 8 m. ertheless, P. acanthocarpus differs from the latter Remarks. The single female specimen is dif- two species in the dissimilar third pereopods, of ferent from the two males in many respects, for which the left is appreciably shorter and stouter. example, the armature of the chelipeds and of the Furthermore, as summarized in Table 2, the gen- carpus of the second pereopods, although the eral armature and ornamentation of the chelipeds coloration in life agrees well for each other. In seems to be more pronounced in P. acanthocar- general, the armature of the chelipeds is more pus sp. nov. and P. handrecki than in P. fasciatus. pronounced in the female specimen than in the Differences between the new species and P. han- two males, whereas the armature of the carpus of drecki are seen in details of the armature and or- the right second pereopod is greatly reduced in namentation of the chelipeds (see Table 2). Col- the female specimen. Similar variation in the ar- oration in life is quite different among the three mature of the chelipeds between different sexes species. For example, P. handrecki has reddish has been reported in other congeneric species brown longitudinal stripes on the ocular pedun- (e.g., McLaughlin and Haig, 1984; Gunn and cles, chelipeds and ambulatory legs (Gunn and Morgan, 1992; Komai and Myorin, 2005; Komai Morgan, 1992; Poore, 2004), whereas no stripes and Osawa, 2006). are seen on those appendages in the other two Pagurixus acanthocarpus sp. nov. is referred to species. The coloration of P. acanthocarpus dif- the P. anceps species group because of the lack fers from that of P. fasciatus as follows. In the of setal rows on the ventral surface of the ulti- new species, the dactyli are dark brown in the mate segment of the antennular peduncle. This proximal one-third, becoming paler distally; each informal species group is represented by the fol- propodus bears a dark brown band occupying lowing 14 described species: P. hectori (Filhol, about proximal one-third, the remainder is white; 1883), P. anceps (Forest, 1954), P. jerviensis the carpi have brown tinge proximally. In P. fas- McLaughlin and Haig, 1984, P. handrecki Gunn ciatus, the dactyli are entirely dark brown; each and Morgan, 1992, P. amsa Morgan, 1993, P. propodus has a white ring occupying the distal granulimanus Morgan, 1993, P. stenops Morgan, one-fourth, and the remainder is generally dark 1993, P. kermadecensis de Saint Laurent and brown with a white patch proximally; the carpi McLaughlin, 2000, P. fasciatus Komai and My- are generally dark brown, but distal parts are orin, 2005, P. longipes Osawa, Fujita and Okuno, white (see Komai and Myorin, 2005). Two new species of Pagurixus from the western Pacific 155 all h ows of ows ne-fourth, obsoletely ridged obsoletely P. handrecki. P. , and P. fasciatus P. sp. nov., sp. nov., P. fasciatusP. handrecki P. scopically granular scopically P. acanthocarpus P. , Pagurixus sp. nov. P. acanthocarpus P. 2 rows of spinulose tubercles 2 rows midline granules on elevated midline elevated arranged in 2 or 3 rows adjacent to arranged in 2 or 3 rows arranged in 1 or 2 rows spines of large rows back ground one-third in proximal dark brown remainder generally as granular ridge dorsomesial margin delimited by delimited by dorsomesial margin of smaller spines single row midline (female) on elevated than right spines large extending onto fixed finger onto fixed extending finger onto fixed extending finger onto fixed spines extending dorsomesial margin delimited by delimited by dorsomesial margin spinulose protuberances coarse granules midline spines on elevated Table 2. Comparison among three species of Items Dorsal surface of palm of palmDorsolateral margin of palmDorsomesial margin finger granular onto fixed coarsely crenulate, extending entire length ridged over distinctly ridge weak delimited by entire length ridged over distinctly distal one-third to one-fourt crenulate smooth, but micro- apparently granular minutely Dorsal surface of palm of palmLateral margin of small spines (male) or with 2 rows Second pereopod carpus distinct ridge delimited by Third pereopods with scattered small tubercles or with 1–5 spines dorsally of spines or tubercles on with row shorter and stouter left appreciably not delimited no spine similar generally of small tubercles with irregular row similar generally no spine Dorsomesial margin of palmDorsomesial margin Dorsal surface of carpus granular irregularly ridge delimited by spines adjacent to of large with 2 rows granular ridge delimited by of small spines with 1 dorsomesial row with 1 or 2 dorsomesial r of small spines row delimited by Dorsal surface of carpusDorsal surface of palm spines large with moderately of palmDorsolateral margin granular with small spines on midline and ridge sharply delimited by with some small spines dorsomesially with irregular dorsomesial margin smooth ridge sharply delimited by smooth nearly of sm row sharply delimited by with spinulose tubercles or small Male right cheliped Left cheliped Male ambulatory legs ambulatory legs Female gonoporesFemale Color of propodi ambulatory legs stripes on white with reddish brown dark brown in distal two-thirds, white left present only unpaired, in distal o white left present only unpaired, paired Female right cheliped Female 156 T. Komai and J. Okuno

The presence of at least one dorsal spine on Komai, T. and E. Myorin, 2005. A new species of the carpus of the right second pereopod links the Pagurixus (Crustacea: Decapoda: Anomura: Paguridae) new species to Pagurixus nanus and P. dissimilis, from southern Japan. Zootaxa, (876): 1–12. Komai, T. and M. Osawa, 2006. A review of the but the poorly developed general armature of the Pagurixus boninensis species group, with descriptions chelipeds and the non-delineated dorsolateral and of six new species (Crustacea: Decapoda: Anomura: dorsomesial margins of both chelae, as well as Paguridae). Zootaxa, (1214): 1–107. the quite different coloration in life immediately Komai, T. and M. Osawa, 2007. A new species of the her- distinguish P. nanus and P. dissimilis from P. mit crab genus Pagurixus Melin (Crustacea: Decapoda: Anomura: Paguridae) from the Indo-West Pacific. Raf- acanthocarpus (cf. Komai and Takada, 2006; fles Bulletin of Zoology, 55: 97–105. Osawa and Komai, 2007). Komai, T. and Y. Takada, 2006. A new species of the her- Etymology. Named in reference to the pres- mit crab genus Pagurixus (Crustacea: Decapoda: ence of spines on the dorsomesial surface of the Anomura: Paguridae) from shallow coral reefs in Ishi- carpus of the right cheliped and the dorsal sur- gaki Island, Ryukyu Islands. Species Diversity, 11: face of the carpus of the right second pereopod in 327–337. McLaughlin, P. A., 2003. Illustrated keys to families and males. genera of the superfamily Paguroidea (Crustacea: De- capoda: Anomura), with diagnoses of genera of Paguri- Acknowledgments dae. Memoirs of Museum Victoria, 60: 111–144. McLaughlin, P. A. and J. Haig, 1984. A review of We thank Hirohito Arima (Izu-Oshima Island), Pagurixus (Decapoda, Anomura, Paguridae) and de- Shigeru Harazaki (Yakushima Island), Eiji My- scriptions of new species. Crustaceana, 47: 121–148. Melin, G., 1939. Paguriden und Galatheiden von Prof. Dr. orin (Kanazawa City), and Naoki Nishimura Sixten Bocks Expedition nach den Bonin-Inseln 1914. (Kashiwa-jima Island, Ohtsuki Town) for donat- Kongliga Svenska Vetenskapsakademiens Handlinger, ing the valuable specimens to us for study. Sin- Serien 3, 18: 1–119. cere thanks are also extended to Patsy A. Morgan, G. J., 1993. Three new species of Pagurixus McLaughlin (Shannon Point Marine Center, (Crustacea, Decapoda, Paguridae) from Western Aus- Western Washington University) and Masayuki tralia, with notes on other Australian species. In: Wells, F. E., D. I. Walker, H. Kirkman and R. Lethbridge Osawa (Department of Marine and Environmen- (eds.), Proceedings of the Fifth International Marine tal Sciences, University of the Ryukyus) for re- Biological Workshop: The Marine Flora and Fauna of viewing the manuscript and for offering valuable Rottnest Island, Western Australia. Pp. 163–181. West- suggestions for improvements. ern Australian Museum, Perth. Osawa, M., Y. Fujita, and J. Okuno, 2006. Two new species of Pagurixus (Crustacea: Decapoda: Anomura: References Paguridae) from submarine caves of the Ryukyu Is- lands, southwestern Japan. Zootaxa, (1148): 27–45. Gunn, S. and G. J. Morgan, 1992. A new species of Osawa, M. and T. Komai, 2007. A new hermit crab Pagurixus (Crustacea: Decapoda: Paguridae) from species of the Pagurixus anceps group (Crustacea: De- southern Australia. Memoirs of Museum Victoria, 53: capoda: Anomura: Paguridae) from southern Japan, 31–41. and supplemental note on P. patiae Komai, 2006. Komai, T., 2006. A new species of Pagurixus Melin, 1939 Zootaxa, (1627): 41–51. (Crustacea: Decapoda: Anomura: Paguridae) from the Poore, G., 2004. Marine Decapod Crustacea of Southern Ryukyu Islands, Japan. Zoosystema, 28: 507–516. Australia. ix574 pp. CSIRO Publishing, Victoria. Komai, T. and A. Asakura, 1995. Pagurixus nomurai, new species, and additional record of Pagurixus maorus Manuscript received 8 May 2008; revised 30 September (Nobili, 1906), hermit from Kume-jima Island, 2008; accepted 15 October 2008. the Ryukyus, Japan (Decapoda: Anomura: Paguridae). Associate editor: T. Komai Journal of Biology, 15: 341–154.