Paguristes palythophilus Ortmann, 1892

Komai, 2001, review of the north-western Paci ® c species of the genus Paguristes Decapoda: Anomura: Diogenidae), I. Five species initially reported Ortmann (1892) from Japan, Journal of Natural History 35 (3), pp. 357-428 : 359-369

Paguristes palythophilus Ortmann, 1892

(®gures 3±6) Paguristes palythophilus Ortmann, 1892: 277 , pl. 12, ®gure 5, 5p, q [type locality: Sagami

Bay]; Doēin, 1902: 645; Alcock, 1905: 155 (bibliography); Balss, 1913: 38; Gordan, 1956:

323 (bibliography); Miyake, 1978: 31 (part), not ®gures 31, 32; Miyake and Imafuku,

1980a: 3 (part); Yu and Foo, 1990: 51, unnumbered ®gure.? Paguristes palithophilu s (sic): Yokoya, 1933: 73.? Paguristes palythophilus: Miyake, 1961: 11 ; Miyake et al., 1962: 125 (list). Paguristes kagoshimensis: Miyake, 1978: 35 (part). Not Paguristes palythophilus: Terao, 1913: 374 .

Not Paguristes palythophilus: Miyake, 1982 : pl. 32, ®gure 4; Takeda, 1982: 58, ®gure 74. [5 Paguristes albimaculatus , sp. nov.].

Material examined. LECTOTYPE (here designated). Sagami Bay , 126±180 m; 1881; coll. L. DoÈderlein; male (SL 11.2 mm), fragmented; MZS 392 (spirit).

Other material. OOE Kochi, Tosa Bay, Shikoku, 190 m; 10 August 1991; RV Toyohata-maru, beam trawl; coll. K. Sasaki; one female (SL 5.3 mm); CBM-ZC 181. OOE Takeoka, Uchibo coast of Boso Peninsula, 80±100 m; 11 June 1998; gill net; coll. T. Komai; one male (SL 10.0 mm); CBM-ZC 4698. OOE Ohgata, Tosa Bay, Shikoku, depth unknown; 13 November 1988; commercial trawler; coll. T. Komai; four males (SL 8.9±10.0 mm), one female (SL 8.1 mm); HUMZ-C 648. OOE Hayama Isshiki, Sagami Bay; 26 February 1930; trawl; one male (SL 9.9 mm); reported by Miyake (1978), det. no. 13; NSMT-CrR 126. OOE Hayama, Sagami Bay; 6 December 1959; trawl; two males (SL 9.9, 10.3 mm), one female (SL 9.4 mm); reported by Miyake (1978), det. no. 307; NSMT-CrR 1658. 5.5 km oOE west of Jogashima Islet, Sagami Bay, 100±110 m; 14 July 1963; one male (SL 8.7 mm); reported by Miyake (1978) as Paguristes kagoshimensis , det. no. 509; NSMT-CrR 2115. Tong-Kong, SW of Taiwan, depth unknown; 30 May 1997; commercial trawler; coll. P. K. L. Ng; one male (SL 7.5 mm); NTOU. Fukuura, Sagami Bay; 1± 12 March 1903; coll. A. Haberer; one male (SL 9.8 mm); No. 1903/7834; ZSM 237/1. Near Misaki, Miura Peninsula, Sagami Bay, 200±300 m; 27 October 1904; coll. F. Doēin; one male (SL 8.2 mm); reported by Balss (1913), No. 2673; ZSM 237/2. Exact locality unknown; 1903; coll. A. Haberer; one ovigerous female, two specimens (size not measured); ZSM 237/3.

Redescription. Thirteen pairs of quadriserial phyllobranchiae.

Shield (®gure 3A) 1.2±1.3 times longer than broad; anterolateral margins sloping; anterior margin between rostrum and lateral projections concave; posterior margin truncate; dorsal surface with paired low elevations, small spines or spinules laterally and scattered tufts of setae. Rostrum narrowly triangular, distinctly over-reaching lateral projections in males, shorter, slightly over-reaching lateral projections in females; apex not acute; dorsal surface not carinate; lateral margins unarmed. Lateral projections obtusely triangular, occasionally with small marginal spine. Branchiostegites (®gure 3C) calci®ed anteriorly and dorsally, with row of small spines on anterodorsal and distal margins.

Ocular peduncles (®gure 3A) moderately slender (6.0±7.0 times longer than width of cornea), 0.7±0.8 times as long as shield, cylindrical, not ināted basally, corneas not dilated; dorsal or dorsomesial surfaces each with longitudinal row of tufts of setae. Ocular acicles subtriangular, terminating in small spine; margins unarmed; separated by 0.7±0.8 of basal width of one acicle.

Antennular peduncles (®gure 3A, B) moderately long, over-reaching ocular peduncles by 0.3 length of ultimate segment. Ultimate segment slender, 1.4 times longer than penultimate segment, with row of long setae on dorsal surface. Penultimate segment without ventral spine. Basal segment unarmed on dorsolateral margin of statocyst lobe and laterodistal margin; ventromesial distal angle produced, terminating in spinule. Antennular ¯agellum longer than ultimate segment of peduncle.

Antennal peduncles (®gure 3A, C) moderately long, slightly over-reaching base of corneas by distal margin of ®fth segment; with supernumerary segmentation. Fifth segment unarmed. Fourth segment with small spine at dorsodistal margin. Third segment with ventromesial distal angle strongly produced, terminating in small spine. Second segment with dorsolateral distal angle weakly produced, terminating in simple or bi®d spine, mesial and lateral margins unarmed; dorsomesial distal angle unarmed or armed with small spine, mesial margin elevated, with few setae. First segment without laterodistal spine, ventromesial margin strongly produced, with one small spine distolateral to antennal gland opening. Antennal acicles relatively long, reaching to distal 0.3 length of ocular peduncles, terminating in simple or bi®d spine, with numerous tufts of long setae; mesial margin with two or three moderately strong spines proximally; lateral margin with one to three spines distally. Antennal ¯agella (®gure 3D) long, 2.3 times longer than shield, exceeding tips of chelipeds, composed of about 60 articles; articles in proximal 0.3 each with several short to moderately long setae or bristles on all surfaces or margins, those in distal 0.7 with long setae every two or three articles, in addition to moderately long setae and bristles.

Endopod of maxillule (®gure 3E) moderately slender, without bristle on mesial margin; internal lobe strongly produced, with eight bristles on rounded distal margin; external lobe very well developed, elongate, strongly recurved, distolateral margin with eight setae. Third maxilliped (®gure 3F) with basis and ischium partially fused; basis unarmed on dorsomesial margin; ischium (®gure 3G) with well developed crista dentata composed of slender corneous teeth, ventral margin with one or two small distal spines; merus with four or ®ve acute spines on ventral margin and one small spine on dorsodistal margin; carpus without dorsodistal spine; dactyl relatively short.

Chelipeds (®gure 4A±D) moderately short, subequal with left slightly larger. Chela subovate in dorsal view, 2.2 times longer than broad. Dactyl 1.5 times longer than palm, noticeably curved ventrally near base; cutting edge with four or ®ve small calcareous teeth (proximal-most two largest) in proximal half and row of small corneous teeth in distal half, terminating in small corneous claw; overlapped by ®xed ®nger; dorsomesial margin with row of moderately small to large, corneoustipped spines decreasing in size distally, and tufts of stiOE setae; dorsal surface with scattered small spinulose tubercles and numerous tufts of stiOE setae; mesial surface with scattered small corneous-tipped spines, accompanied by tufts of very short setae and row of tufts of stiOE setae near dorsal margin; ventral surface unarmed, but with few tufts of stiOE setae. Palm subequal in length to carpus; dorsomesial margin with ®ve to seven strong, occasionally corneous-tipped, spines and tufts of long stiOE setae; dorsal surface sloping to lateral face without delineation of dorsolateral margin, bearing several irregular rows of small to moderately large spines or tubercles, extending onto ®xed ®nger; mesial surface with row of few denticulate protuberance s near dorsomesial margin and few scattered low protuberance s accompanied by tufts of short setae, mesiodistal margin unarmed; lateral surface with scattered moderately small spines or spinulose tubercles; ventral surface with row of low protuberance s accompanied by tufts of long setae on midline, extending onto ®xed ®nger, and small tubercles or protuberance s laterally and mesially. Fixed ®nger deēxed, depressed ventrally near base; cutting edge concave proximally, with row of small calcareous teeth, terminating in small corneous claw; with small hiatus when closed. Carpus about 0.6 times as long as merus; dorsomesial margin with row of ®ve or six strong spines; dorsal surface with tufts of stiOE setae and small spines or spinulose tubercles mesial to sinuous sulcus, dorsodistal distal margin produced, with row of small spines lateral to articular knob; dorsolateral margin indicated by row of small multi®d tubercles; mesial surface with two rows of low protuberances accompanied by tufts of stiOE setae dorsally; lateral surface with scattered small spinulose tubercles and low protuberances accompanied by tufts of short stiOE setae, laterodistal margin weakly protuberant; ventral surface unarmed, ventrodistal margin produced, with spinule. Merus moderately deep; dorsal surface with row of short transverse multispinose ridges or spinulose tubercles, becoming obtuse proximally, accompanied by row of long setae, distalmost ridge extending to lateral and mesial faces; dorsodistal margin with row of small spines; mesial surface with scattered low protuberances, sometimes accompanied by tufts of short setae, and deep groove along subdistal ridge, ventromesial margin with row of small spines and spinulose tubercles and sparse tufts of setae; lateral surface with numerous short, denticulate ridges, accompanied by short bristles, ventrolateral margin protuberant or spinulose in distal 0.3; ventral face unarmed, with numerous tufts of long setae. Ischium with row of tiny tubercles on ventromesial margin, ventrolateral distal angle unarmed. Coxa unarmed.

Second pereopods (®gure 5A, B) moderately long and slender. Dactyls long, 1.5±1.7 times longer than propodi; weakly curved in lateral view, nearly straight in dorsal view; terminating in strong, curved, corneous claw; dorsal surfaces slightly protuberant, with numerous, dense tufts of long setae, lacking corneous-tipped spinules proximally; mesial surfaces unarmed, but with two rows of numerous tufts of long setae dorsally and ventrally; lateral surfaces with three rows of tufts of setae (dorsal row extending from base to 0.6 length, middle row, slightly dorsal to midline, extending distally from midlength); ventral margins each with row of 25±42 slender corneous spinules. Propodi distinctly longer than carpi; dorsal surfaces each with row of small spines mesially, becoming weak distally, and tufts of long setae; mesial surfaces unarmed, but with two rows of tufts of long setae; lateral surfaces with low protuberances near dorsal margin, accompanied by tufts of setae, and two rows of tufts of setae on midline and near ventral margin; ventral surfaces slightly protuberant, unarmed, with double or single row of tufts of long setae, ventrodistal margin unarmed. Carpi moderately long; dorsal surfaces with double row of moderately small spines mesially and tufts of long setae; mesial surface with few tufts of short setae; lateral faces each with tufts of stiOE setae on midline and faint longitudinal sulcus lined by row of setae; ventral surfaces with few tufts of long setae, ventrodistal margins with long setae. Meri strongly compressed laterally; dorsal surfaces slightly protuberant, with numerous tufts of moderately long to long setae, lacking spinules; mesial surfaces with few tufts of short setae dorsally; lateral surfaces with scattered short vertical rows of short setae; ventral surfaces with row of spinules in distal half mesially and numerous tufts of long setae, both ventromesial distal and ventrolateral distal margins unarmed. Ischia with or without spinules on dorsal surfaces; ventral surfaces unarmed. Coxae unarmed.

Third pereopods (®gure 5C, D) generally similar to second in setation. Dactyls more strongly curved than in second, somewhat ¯attened dorsoventrally in distal half; dorsal surfaces more strongly protuberant in distal half than in second, accompanied by tufts of dense stiOE setae; mesial surfaces each with row of tufts of moderately short setae on midline and dense row of tufts of long setae near ventral margin; lateral surfaces with three rows of tufts of setae (dorsal and middle rows conūent in distal half); ventral margins with 26±34 slender corneous spinules. Propodi slightly protuberant on dorsal surfaces; mesial surfaces unarmed, but with three or four rows of tufts of short to moderately long setae. Carpi unarmed on dorsal surfaces except for moderately small dorsodistal spine. Meri slightly protuberant on dorsal surfaces; ventral surfaces unarmed, both dorsomesial distal and dorsolateral distal margins unarmed. Ischia unarmed on dorsal and ventral faces. Coxae unarmed; females with paired gonopores.

Fourth pereopods (®gure 3H) thickly setose on dorsal and ventral faces. Dactyl (®gure 3I) slightly curved, terminating in small corneous claw; dorsal surface unarmed; ventral surface with row of small corneous teeth laterally and chitinous tube-like preungual process arising from proximal to base of terminal claw. Propodus moderately stout, with almost straight ventral margin; dorsal surface unarmed; propodal rasp composed of four or ®ve rows of corneous scales, becoming fewer proximally, extending to half length of ventral margin. Carpus without dorsodistal spine.

Fifth pereopods chelate, setose. Coxae in males each with gonopore.

First and second pleopods in males paired, modi®ed. First pleopod (®gure 6A±C) with double or triple row of long setae on mesial face of basal segment. Inferior lamella strongly twisted, with distinct longitudinal ridge on ventral surface, continuous with proximolateral margin; distal margin broadly rounded, with single row of moderately strong, closely-set, hooked corneous spines; mesial margin with several rows of bristles, extending onto ventral surface proximally; lateral margin strongly sinuous. External lobe well developed, rounded, not reaching distal margin of inferior lamella. Internal lobe moderately large, rounded, separated from basal lobe by deep U-shaped notch; mesial margin with dense, long setae.

Second pleopod (®gure 6D, E) with basal segment somewhat ¯attened, with few short setae basally. Endopodite slightly twisted, margins bluntly edged, with row of tufts of short setae on ventrolateral margin and tuft of long setae at ventrodistal margin; lateral face weakly concave. Appendix masculina elongate in distal part, strongly twisted; articulation suture discernible only on interior (mesial) face; distal margin rounded; dorsal margin with dense bristles; ventral margin slightly produced at level of midlength, with tuft of long setae; exterior (lateral) face with several irregular rows of dense bristles along dorsal margin; interior (mesial) face with few long setae.

Third to ®fth pleopods of males unpaired, similar in size, exopods very well developed, endopods rudimentary.

Females with ®rst pleopods (®gure 6F) paired; articulation between basal and distal segments obscure; distal segment more slender than basal segment. Second to ®fth pleopods unpaired; second to fourth pleopods with both rami well developed, exopods much longer than endopods, multiarticulated, endopod incompletely biarticulated; ®fth pleopod much shorter than preceding pleopods, with exopod well developed, not articulated, endopod vestigial.

Brood pouch (®gure 6G) relatively small, subtriangular, margins with thick, very long plumose setae. Second to fourth abdominal tergites somewhat calci®ed on left, each with moderately dense, long setae on left margins, obscuring pleopods; ®fth tergite not concealed by brood pouch.

Telson (®gure 3J) with posterior lobes strongly asymmetrical, left lobe larger than right; each lobe subtriangular with rounded apex, separated by moderately deep median cleft, terminal and lateral margins unarmed but with long setae; lateral indentations distinct; anterior lobes unarmed on convex lateral margins.

Coloration. In life: entire animal orange ±red generally; spines, tubercles, protuberances on chelipeds and ambulatory pereopods showing as white spots. Ocular peduncles with two white longitudinal stripes dorsolaterally and mesially, dorsal surface between two white stripes generally orange, becoming darker mesially, with longitudinal row of white spots; lateral and ventral faces deep red. Antennular peduncles orange, ¯agellum white. Antennal ¯agellum generally red, paler proximally.

Variation. The available material suggests that the shape of the rostrum shows a sexual dimorphism in P. palythophilus . The rostrum is much more strongly produced, distinctly over-reaching the lateral projections, and narrower, in males than in females.

Size. Largest male: SL 11.2 mm; largest female: SL 9.4 mm.

Habitat and symbiotic association. Inhabits gastropod shells encrusted with polyps of Epizoanthus ramosus .

Distribution. Known with certainty from Sagami Bay, Uraga Canal oOE Boso Peninsula, Tosa Bay, and SW Taiwan; 80± 180 m.

Remarks. Although Ortmann (1892: 279) cited two specimens in his original description of Paguristes palythophilus , only one male specimen was located in the collection of the MuseÂe Zoologique, Strasbourg. As Ortmann did not designate a holotype, that specimen has been selected as a lectotype. Unfortunately, the lectotype of P. palythophilus is now in an extremely poor condition. It was once dried and thus the integument of the body parts is very fragile and is easily broken. I meticulously examined the lectotype and the following features are still recognizable: the rostrum is narrow, strongly produced; the mesial face of the dactyl of the cheliped is armed with numerous small corneous spines; the ®xed ®nger of the chela is noticeably deēxed, the palm bears numerous spinulose protuberance s and tubercles on the lateral face. In addition, Ortmann (1892) indicated the commensalism with Epizoanthus (as Palythoa ) polyps. The observed morphology and symbiotic association and a comparison with additional material enable me to establish the speci®c identity of P. palythophilus .

The unarmed terminal margins of the telson provides evidence that P. palythophilus should be placed in group B of the genus (cf. McLaughlin and Provenzano, 1974b). This species is similar to, and has often been confused with, P. albimaculatu s sp. nov. Nevertheless, there are some minor but distinct diOEerences between the two. The ultimate segment of the antennular peduncle is relatively longer in P. palythophilus than in P. albimaculatu s (1.4 times versus 1.1±1.2 times length of the penultimate segment). In addition, from the dorsal view, that segment seems to be much more slender in P. palythophilus than in P. albimaculatus . The corneous spines on the dactyls of the ambulatory pereopods are much smaller and more numerous in P. palythophilus than in P. albimaculatus (25±42 versus 15±20). The chelae have more numerous scattered spinulose tubercles on the lateral face in P. palythophilus than in P. albimaculatus . The mesial face of the dactyl of the cheliped is armed with numerous corneous spinules in P. palythophilus . In contrast, the mesial face of the dactyl of the cheliped bears fewer and stronger corneous spines in P. albimaculatus . The rostrum of the male is much more slender and more strongly produced in P. palythophilus than in P. albimaculatus . The live coloration is quite diOEerent between the two species: in P. palythophilu s, the dorsal surface of the ocular peduncle has two white longitudinal stripes dorsolaterally and mesially, and the space between the two stripes is orange, with a longitudinal row of white spots; the lateral and ventral faces are deep red; the ambulatory pereopods are generally orange ±red. In P. albimaculatus , the dorsal surface of the ocular peduncles is white, occasionally with a medial longitudinal stripe of red, and the remaining surfaces are deep orange±red. The ambulatory pereopods bear scattered white spots on a red background. In addition, the available material suggests that P. palythophilus lives in shells always encrusted by polyps of Epizoanthus ramosus . So far, no association with Epizoanthus has been recorded for P. albimaculatus .

Paguristes palythophilus is also similar to P. versus sp. nov. However, the mesial faces of the dactyl of the cheliped which are armed with numerous scattered small spines, but lack a distinct ventral row of small spines, immediately separates P. palythophilus from P. versus .

In addition to Ortmann (1892), Doēin (1902) and Balss (1913) reported P. palythophilus from Sagami Bay. Having re-examined the material reported by Balss (1913) from Sagami Bay, I con®rmed that his identi®cation was correct. Terao (1913) reported P. palythophilus based on a single male specimen from Misaki, Miura Peninsula, but he remarked on the relative shortness of the rostrum and of the ambulatory pereopods of his specimen in comparison with the original description by Ortmann (1892). I have been unable to locate Terao’s material. It is impossible to decide what species he was actually reporting without an examination of his specimen. Yokoya (1933) reported P. palythophilus (as P. palithophilus ) from several Japanese localities but provided only a reference to Ortmann’s description and ®gure. Miyake (1961) included P. palythophilus in the list of decapods from Amakusa, western Kyushu. It is not possible to ascertain the identities of the specimens reported by Yokoya (1933) and Miyake (1961), because their specimens have not been available for examination. Therefore their references can only be included in the synonymy. Miyake (1978) reported P. palythophilus from Sagami Bay. He described the colour of the ocular peduncles as`Eyestalks white; median line of dorsal surface, mesial and lateral margins each with red stripe; ventral face uniformly red’. This colour pattern is consistent with P. albimaculatus rather than P. palythophilus . I have re-examined part of Miyake’s specimens (NSMT-CrR 126, 1658, and 2393) identi®ed with P. palythophilus and found that two species were actually confounded. The three specimens (NSMT-CrR 126 and 1658) were correctly identi®ed with P. palythophilu s, but the remaining two specimens (NSMT-CrR 2393) actually represent P. albimaculatus . Judging from the magni®ed size and the length of the rostrum, Miyake’s (1978: text-®gure 10) ®gure (showing the anterior part of the shield and cephalic appendages and the mesial face of the dactyl of the right chela) most certainly depicts the male specimen (NSMT-CrR 2393) here referred to P. albimaculatus , though Miyake did not specify which specimen he illustrated. Additionally, it has been found that the male specimen (NSMT-CrR 2115; Miyake det. no. 509) referred to P. kagoshimensis is also P. palythophilus . Although the specimens reported by Miyake (1982) and Takeda (1982) have not been re-examined, from the colour illustration, they are clearly referable to P. albimaculatus . Yu and Foo (1990) reported P. palythophilus from Taiwan, with a colour photograph. Although they did not provide detailed information on morphology, the photographed specimen closely agrees with P. palythophilus in the colour pattern of the ocular peduncles. The occurrence of the species in Taiwan has been con®rmed by the specimen from oOE Tong-Kong ( NTOU).