THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(2): 461-473 A NEW SPECIES OF PAGURITTA (CRUSTACEA: DECAPODA: ANOMURA: PAGURIDAE) FROM THE WESTERN PACIFIC, PREVIOUSLY CONFUSED WITH P. HARMSI OR P. GRACILIPES Tomoyuki Komai and Eijiroh Nishi ABSTRACT.-A comparison of specimens from Kushimoto (Kii Peninsula, Honshu mainland, Japan), Okinawa-jima Island (Ryukyu Archipelago), Ogasawara (=Bonin) Islands, and Philippine Archipelago, has revealed that McLaughlin & Lemaitre (1993) mixed two species under the name Paguritta gracilipes. One of them is described and illustrated as new species, Paguritta vittata. Paguritta gracilipes Melin, 1939 s. str., appears to be restricted to Ogasawara Islands. While the new species is considered to be distributed from southern Japan to Philippines, it does not occur in Ogasawara Islands. The new species shows a strong sexual dimorphism in morphology of the palm of the right cheliped and relative stoutness of the ambulatory pereopods. Its closest relative is P. harmsi (Gordon, 1935), and characters distinguishing the two species are discussed. An emended key to the species of the genus is provided. INTRODUCTION Melin (1939) described a new taxon, Paguritta gracilipes based on two specimens, one male and one female, from Takinoura, Ogasawara Islands (=Bonin Islands). Although the species long had been considered to be a synonym of P. harmsi (Gordon, 1935) (see Forest, 1961; Miyake, 1978; Lewinsohn, 1978), McLaughlin & Lemaitre (1993) concluded that P. gracilipes was a species distinct from P. harmsi. Lewinsohn (1978) and McLaughlin & Lemaitre (1993) indicated that differences of coloration were sufficiently reliable to recognition of closely related species of Paguritta. Without confirmation of the coloration of true P. gracilipes, however, McLaughlin & Lemaitre (1993) assumed that a single specimen from Philippines, examined by Schumacher (1977) and Lewinsohn (1978), represented P. gracilipes. McLaughlin & Lemaitre (1993) considered that the striped color patterns of the chelipeds reported by Lewinsohn (1978) and figured by Schumacher (1977) applied to P. gracilipes as a diagnostic character of that species. Tomoyuki Komai, Eijiroh Nishi -Natural History Museum and Institute, Chiba, 955-2 Aoba-cho, Chuo-ku, Chiba 260, Japan. 461 Komai & Nishi: A new species of Paguritta We had an opportunity to compare IS specimens of a species, which showed coloration agreeing well with the description of P. gracilipes given by McLaughlin & Lemaitre (1993), from Okinawa-jima Island and Kushimoto, Kii Peninsula, Japan, with three topotypic specimens of P. gracilipes from Ogasawara Islands, which closely agree with the detailed accounts of the syntypes of that species provided by McLaughlin & Lemaitre (1993) in morphological characters. The former have brown stripes on the chelipeds, ocular peduncles and body, while the topotypic material of P. gracilipes had an entirely different coloration: the chelipeds are mottled with orange, light purple and cream, and the ocular peduncles and body are uniformly cream yellow. Furthermore, it was found that the number of ventral spines on the ambulatory dactyls was fewer in the striped specimens than in the Ogasawara specimens (three to five versus six or seven). This character was used by McLaughlin & Lemaitre (1993) to separate it from all other members of the genus. Our observations indicate that the species with the striped color pattern represents an undescribed taxon. The Philippine specimen reported by Schumacher (1977) and Lewinsohn (1978) has been reexamined and is referred to the new species. The specimens examined, including the type series of the new species, are deposited in the Natural History Museum and Institute, Chiba, with a code of CBM-ZC, and the Nationaal Natuurhistorisch Museum, Leiden, The Netherlands (RMNH). The abbreviation SL is used for shield length, as measured from the tip of the rostrum to the midpoint of the posterior margin of the shield. Illustrations were made with the aid of drawing tube mounted on a OLYMPUS SZH. Terminology follows that of McLaughlin & Lemaitre (1993) in general, but Lemaitre (199S) is referred to for the posterior carapace structure. Data of the comparative specimens of P. gracilipes are as follows: CBM-ZC 2276, male (SL 2.7 mm), 2 females (SL 3.5, 3.8 mm), Tsurihama, Chichi-jima Island, Ogasawara Islands, l.S-3 m, SCUBA diving, colI. E. Nishi, 27 Jun.199S. DESCRIPTION Paguritta vittata, new species (Figs. 1-5) Orthopaguropsis harmsi: Serene, 1957: lO7, figs. 1-3. Paguritta harmsi: Forest, 1961: 238 (in part); Schumacher, 1977: 371, figs. 1,2; Lewinsohn, 1978: 245 (in part); Miyake, 1982: 121 (in part), pI. 41 fig. 2 left (male); Takeda, 1986: 124, unnumbered color fig.; Kamezaki et aI., 1988: 124, unnumbered color fig.; Imafuku, 1992: 235, unnumbered color fig. Paguritta gracilipes: McLaughlin & Lemaitre, 1993: 5 (in part); Takeda, 1994: 198, fig. 1; Asakura, 1995: 367 (in part), pI. 97 fig. 14. Material examined.-Holotype- ovig. female (SL 2.8 mm) (CBM-ZC 2168), Zanpa-misaki, Okinawa-jima Island, Ryukyus, 26°26.3'N, 124°27.8'E, 1-2 m, coll. E. Nishi (SCUBA diving), 23 Mar. 1995. Paratypes- 1 male (SL 2.1 mm), 1 female (SL 2.2 mm) (CBM-ZC 2169), data as for holotype; 1 ovig. female (SL 2.1 mm) (CBM-ZC 2170), Zanpa-misaki, Okinawa-jima Island, 1-2 m, colI. E. Nishi (SCUBA diving), 3 Aug.1992; 2 females (SL 2.3, 3.2 mm), 1 juv. (SL 1.0 mm) (CBM-ZC 2264), Maeda-misaki, Okinawa-jima Island, 26°26.3'N, 124°3IA'E, 1-2 m, coIl. E. Nishi (SCUBA diving), 30 May.1990; 1 ovig. female (SL 3.1 mm) (CBM-ZC 2265), data as for holotype; 1 male (SL 2.2 mm) (CBM-ZC 2266), Andonohana, Kushimoto, Kii Peninsula, 33°21.8'N, 135°45.1 'N, lO m, colI. K. Nomura (SCUBA diving), 7 Jun.1995; 3 males (SL 1.9-2.5 mm) (CBM-ZC 2275),1 female (SL 2.2 462 THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(2) mm), I ovig. female (SL 2.7 mm), Zanpa-misaki, 2-5 m, coIl. E. Nishi (SCUBA diving), 5 May.1995. Others: 1 male (SL 2.1 mm) (RMNH D 31935), Philippine Islands (from aquarium), 1973, identified as Paguritta gracilipes by McLaughlin & Lemaitre (1993). Description of females.-Shield (Fig. 2A, B) longer than broad (ratio of shield length/ breadth 1.13-1.30), dorsal surface almost glabrous, but with few scattered tufts of short setae; anterior margin between rostrum and lateral projections concave, without row of setae; anterolateral margins sloping. Rostrum prominent, triangular, terminating in spinule. Lateral projections obtusely triangular, armed with minute terminal spinule. Posterior carapace (Fig. 2B) membranous except for moderately well calcified posteromedian plate, with sparse row of tufts of setae on branchial region; posteromedian plate separated in two sections by distinct transverse suture and row of setae; cardiac sulci slightly divergent posteriorly, extending nearly to posterodorsal margin; sulci cardiobranchialis strongly convergent and connecting posteriorly with cardiac sulci. Ocular peduncles (Fig. 2A) shorter than shield (ratio of ocular peduncle length/shield length 0.75-0.92), slightly broadened basally and slightly constricted medially; corneae slightly dilated. Ocular acicles elongate, narrow, terminating in strong spine, with acute or subacute lateral or submarginal spine; separated basally by about half basal width of one acicle. Antennular peduncles (Fig. 2A) reaching beyond distal margin of cornea; basal segment with unarmed mesial and lateral surfaces. Antennal peduncle (Fig. 2A, C) reaching or overreaching distal margin of corneae; fifth and fourth segments with few scattered setae; third segment without spine at ventrodistal margin; second segment stout, with dorsolateral distal angle strongly produced, terminating in acute spine and with two or three additional spines on mesiodistal margin, dorsomesial distal angle unarmed. Antennal acicle reaching base of cornea, terminating in small spinule and with long marginal setae. Antennal flagellum (Fig. 2D) long, each article with one or two short setae and pair of long setae bearing minute setules. Mandible (left) (Fig. 3A) with incisor process bearing two acute teeth at anteromesial corner; palp three-segmented. Maxillule (Fig. 3B) with well-produced, triangular external lobe of endopod, internal lobe with two setae. Maxilla (Fig. 3C) with endopod slightly inflated proximally, reaching anterior margin of scaphognathite. First maxilliped (Fig. 3D) with endopod reaching beyond anterior margin of distal endite. Second maxilliped (Fig. 3E) with basis-ischium fusion incomplete. Third maxilliped (Fig. 3F) with basis-ischium fusion incomplete; ischium (Fig. 30) with well developed crista dentata, one accessory tooth (rarely two teeth present on either side); merus and carpus unarmed. Right cheliped (Fig. 4A-C) with chela moderately broad, dorsomesial margin strongly convex. Dactyl approximately as long as palm, terminating in strong calcareous claw; cutting edge with row of small calcareous teeth; dorsal surface with numerous long setae and few small spinules basally; dorsomesial margin with row of acute spines. Palm about as long as carpus; dorsal margins of palm and fixed finger circumscribed by row of prominent, relatively stout or slender curved spines, five or six on dorsomesial margin strongest; dorsal surface nearly flattened, armed with scattered small spines or spinules sometimes appearing as irregular rows, also with numerous scattered long setae; fixed finger with dorsal surface bearing small spines basally, cutting edge with row of small calcareous teeth and terminating 463 Komai & Nishi: A new species of Paguritta in calcareous claw; mesial, lateral and ventral surfaces of palm all glabrous, lateral surface hardly visible from dorsal view, ventral surfaces of dactyl and fixed finger with scattered tufts of moderately short setae. Carpus subequal to merus in length; dorsomesial distal angle unarmed; dorsolateral margin armed with row of three spines and moderately strong dorsodistal spine; dorsal surface with scattered long setae distally; mesial, lateral and ventral surfaces glabrous, with long setae ventrodistally. Merus and ischium unarmed but with few long setae dorsodistally or ventrally. Left cheliped (Fig. 4D-F) with dactyl slightly shorter than palm, cutting edge with row of small corneous teeth and terminating in small corneous claw; dorsal surface unarmed, but with scattered long setae; dorsomesial margin with row of small spines and long setae. Palm distinctly shorter than carpus; propodal-carpal articulation rotated clockwise 15-30° from perpendicular; dorsomesial margin sloping, with few small spines, dorsal surface with numerous scattered setae but without spines, dorsolateral margin with row of strong spines slightly curved upward and decreasing in size on fixed finger; cutting edge of fixed finger with row of small calcareous teeth and terminal calcareous claw; ventral surfaces of fixed finger and dactyl with scattered tufts of long or short setae. Carpus subequal to length of merus; dorsodistal margin armed dorsally with three strong spines and mesially with one small spine, unarmed laterally; dorsal surface with one moderately strong spine and numerous long setae. Merus with few small tubercles ventrally. Merus and ischium almost glabrous, with few setae dorsally and numerous setae ventrally. Second pereopods (Fig. 4G) longer than third (Fig. 41); dactyls of both (Fig. 4H, I) 0.6 times as long as propodi, terminating in strong corneous claws, dorsal surfaces and mesial and lateral faces all with long setae, ventral margins each with three or four (rarely five) long corneous spines. Propodi distinctly longer than carpi, dorsal and ventral surfaces with scattered long setae, ventrodistal angles each with single corneous spine; carpi and meri unarmed, but with scattered long setae dorsally and shorter setae ventrally. Ischia of second and third pereopods generally similar in shape; coxae of third pereopods (Fig. 2E) each with large gonopore. Fourth pereopods (Fig. 3H) relatively stout, subchelate; dactyl stout, strongly curved, with row of corneous spines on ventral margin; propodal rasp composed of single row of corneous scales; distal three segments with numerous setae on dorsal surfaces. Fifth pereopods chelate. Sternite of third pereopods (Fig. 2E) with anterior lobe subrectangular, anterior margin armed with four to six rather acute spines. Sternite of fifth pereopods (Fig. 2F) divided into two distinct lobes, each with prominent anteriorly directed acute spine. Abdomen nearly straight, with biramous pleopods on left side of second to fourth somites. Uropods (Fig. 2G, H) with moderately short protopods bearing cluster of 6-8 small tubercles; exopods elongate, 3.5 times as long as wide; endopod reaching beyond exopodal bases. Telson (Fig. 2G) with posterior lobes and anterior lobes separated by prominent transverse suture; terminal margins of posterior lobes each with 7 to 9 moderately strong calcareous spines interspersed with 1 or 2 smaller spines. Description of males.-Right cheliped (Fig. SA, G) with chela more or less elongate. Dactyl approximately as long as palm. Palm distinctly longer than carpus; dorsal margins of palm circumscribed by row of moderately strong, curved spines, spines on weakly convex 464 THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(2) to nearly straight dorsomesial margin curved inward; dorsal surface varying from almost flat to convex, with few spinules; lateral surface partially visible from dorsal view. Ambulatory pereopods (Fig. SC, D) relatively longer and more slender than in females. Gonopores on coxae of third pereopods (Fig. SE) relatively smaller than those in females. Gonopores on coxae of fifth pereopods (Fig. SF) obscured posteriorly by row of setae; vas deferens protruded. Abdomen without paired or unpaired pleopods. Coloration in life (Fig. 1). -Shield cream-yellow with four brown stripes (two submedian and two along lateral margins). Ocular peduncles with four brown stripes on cream background; corneae deep brown; acicles cream. Antennular and antennal peduncle cream in general, second segment of antennal peduncle pale brown; antennal flagellum generally brown dorsally with transparent area in proximal one-fourth. Posterior carapace with two brown stripes continuing from two submedian stripes on shield; pterygostomian region grayish. Abdomen dorsally with four brown stripes on cream background. Maxillipeds grayish green or grayish blue. Chelipeds similarly colored, entirely cream-yellow with dark brown stripes; dorsal surface of palm with three stripes, lateral and mesial faces with one stripe; carpus with five stripes in total, each continuing with stripe on palm. Ambulatory legs cream. Biological notes.-Paguritta vittata usually lives in calcareous tubes of Spirobranchus corniculatus Grubc (Polychaeta: Serpulidae), and rarely in tubes of other species of serpulid polychaetes or shells of Dendropoma sp. (Gastropoda: Vermetidae), which were usually associated with the living massive or plate-like coral, Porites spp. The eggs of P. vittata are quite large, globular in shape, measuring 0.79-0.93 mm in diameter. The number was relatively few for pagurids, 48 in one ovigerous specimen (CBM ZC 227S, SL 2.7 mm). This observation suggests that this species may have an abbreviated larval development. Distribution.-Southern Japan northward to Kii Peninsula, Ryukyu Archipelago, Philippines and Vietnam; subtidal to 10 m. Etymology.-The name is from the Latin vittatus (=with stripes), referring to the characteristic striped color pattern on the chelipeds and the body. DISCUSSION Paguritta vittata appears closest to P. harmsi, the two showing characters such as five or fewer than five ventral spines on the ambulatory dactyls, and dorsal surface of the left palm with few spinules. Our observation confirms McLaughlin & Lemaitre's (1993) indication that Paguritta gracilipes is readily distinguished from all other members of Paguritta in having more numerous ventral spines on the ambulatory dactyls, i.e., six to eight versus five or less than five. McLaughlin & Lemaitre (1993) indicated that living color was the most diagnostic 465 Komai & Nishi: A new species of Paguritta Fig. 1. Paguritta vittata, new species. Top, paratype male from Kushimoto, SL 2.2 rum, CBM-ZC 2266 (photo courtesy of K. Nomura), inhabiting a tube in the coral Porites sp.; Bottom, female just outside tube hausing, from Zanpa-misaki, Okinawa-jima Island, specimen not preserved (photo taken by E. Nishi). 466 THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(2) E ~( B AGO 1 mm CS PMP J:.,--.:.,.,--t-- sc B mm Fig. 2. Paguritta vittata, new species. Holotype female, SL 2.8 mm, CBM-ZC 2168. A, shield and cephalic appendages, dorsal; B, carapace, dorsal; C, left antennal peduncle, lateral; D, proximal part of antennal flagellum, dorsolateral; E, coxae and sternal lobes of third pereopods, ventral; F, sternal plate of fifth pereopods, ventral; G, telson, posterior section of sixth abdominal tergite and basal part of uropods, dorsal; H, left uropod, lateraL Abbreviations are as follows: CS=cardiac sulcus; PMP=posteromedian plate; SCB=sulcus cardiobranchialis. . 467 Komai & Nishi: A new species of Paguritta G H A-E mm F mm GH O.5mm Fig. 3. Paguritta vittata, new species. Holotype female, SL 2.8 mm, CBM-ZC 2168. Left mouthparts and fourth pereopod. A, mandible, internal; B, maxillule, external; inset, endopod, lateral; C, maxilla, external; D, first maxilliped, external; E, second maxilliped, external; F, third maxilliped, lateral; G, same, ischium, internal; H, fourth pereopod, lateral. 468 THE RAFFLES BULLETIN OF ZOOLOGY 1996 44(2) H ~ J~ GI HJ 1 mm O.5mm Fig. 4. Paguritta vittata, new species. Holotype female, SL 2.8 mm, CBM-ZC 2168. A, right chela, dorsal, setae omitted; B, right cheliped, mesial, setae omitted; C, same, lateral; D, left chela, dorsal, setae omitted; E, left cheliped, mesial, setae omitted; F, same, lateral; G, left second pereopod, lateral; H, dactyl of same, mesial, setae omitted; I, left third pereopod, lateral; J, dactyl of same, setae omitted. 469 Komai & Nishi: A new species of Paguritta F~ C G D A-DG 1 mm E F 1 mm Fig. 5. Paguritta vittata, new species. A-F, paratype male from Kushimoto, SL 2.2 mm, CBM-ZC 2266; G, paratype male from Zanpa-misaki, Okinawa-jima, SL 2.5 mm, CBM-ZC 2275. A, right chela, dorsal, setae omitted; B, same, mesial, setae omitted; C, left second pereopod, lateral, setae omitted; D, left third pereopod, setae omitted; E, coxae and sternal lobes of third pereopods, ventral; F, coxae of left fifth pereopod, lateral; G, right chela, dorsal, setae omitted. 470