Pagurus moluccensis Haig & Ball, 1988

Komai, Tomoyuki & Rahayu, Dwi Listyo, 2004, Redescription Of Pagurus Moluccensis Haig & Ball, 1988, With Description Of A New Species Of Pagurus From Indonesia, And Taxonomic Notes On The Pagurus Anachoretus Group (Crustacea: Decapoda: Anomura: Paguridae), Raffles Bulletin of Zoology 52 (1), pp. 183-200 : 184-191

Pagurus moluccensis Haig & Ball, 1988

( Figs. 1A , 2-5 )

Pagurus moluccensis Haig & Ball, 1988: 187 , figs. 14, 15; Komai & Osawa, 2001: 1291.

Material examined. – Holotype - male (sl 2.1 mm) ( NIOJ-A 009 ), north side of Banda Besar, south side of Selat Lontor, 7 Apr.1975.

Other material - 5 males (sl 2.0- 2.3 mm), 4 females (sl 1.7-2.0 mm), 1 ovigerous female (sl 1.8 mm) ( CBM-ZC 5569 ), Marsegu Island , intertidal, coll. La Pay, 9 Feb.1994 ; 1 male (sl 2.1 mm), 1 female (sl 1.8 mm), 1 ovig (sl 1.5 mm) ( MZB Cru 1505), same data ; 1 male (sl 2.3 mm), 3 ovigerous females (1.9-2.5 mm) ( CBM-ZC 5570 ), Lembeh Strait , north of Sulawesi, intertidal, 25 Jun.1996 ; 1 male (sl. 2.4 mm), 1 ovigerous female (2.0 mm) ( ZRC 2002.0517 ), same data ; 1 female (sl 2.0 mm) ( CBM-ZC 5571 ), Tanawanako , north of Sulawesi, intertidal, 21 Dec.1997 .

Redescription. – Eleven pairs of biserial phyllobranchiae. Calcified parts of integument of body and appendages with low, blister-like tubercles of various shape and size ( Figs. 2A, B, F, H , 3G, J ).

Cephalothorax somewhat depressed dorsoventrally. Shield ( Fig. 2A ) about as long as broad; anterior margin between rostrum and lateral projections slightly concave; anterolateral margins sloping; posterior margin truncate; rostrum broadly rounded, slightly exceeding lateral projections; lateral projections obsolete, without terminal spine; dorsal surface flat to slightly convex, with numerous blister-like tubercles; paragastric grooves conspicuous; dorsal surface with tufts of setae laterally. Posterior carapace ( Fig. 2B ) membranous except for weakly calcified anterior part of posteromedian plate and submedian parts either side of posteromedian plate; submedian parts with numerous small, blister-like tubercles; branchial region with few setae; cardiac sulci converging posteriorly, reaching nearly to posteromedian margin of carapace; sulci cardiobranchialis short, somewhat divergent posteriorly.

Ocular peduncles ( Fig. 2A ) 0.7-0.8 times as long as shield, moderately stout, weakly inflated basally, corneas not dilated; dorsal surfaces each with row of tufts of short setae mesially. Ocular acicles ( Fig. 2C ) triangular, terminating in sharp marginal spine; dorsal surfaces nearly flat. Interocular lobe ( Fig. 2C ) prominent, with paired long processes each terminating acutely or subacutely, not reaching distal margins of ocular acicles.

Antennular peduncles ( Figs. 2A , 3A ) stout, reaching or slightly overreaching distal margins of corneas; ultimate segment 1.5-1.6 times as long as penultimate segment, somewhat broadened distally in lateral view, with few setae on dorsal surface; basal segment with distolateral margin slightly produced, ventromesial distal margin unarmed, statocyst lobe unarmed on lateral face.

Antennal peduncles ( Fig. 2A ) overreaching distal margins of corneas by 0.1-0.3 length of fifth segment. Fifth segment moderately stout, with few short setae. Fourth segment with few short setae. Third segment with small tubercle at ventromesial distal angle and few short setae. Second segment with dorsolateral distal angle produced, reaching midlength of fourth segment, terminating in small spine, unarmed on mesial margin; dorsomesial distal angle unarmed, mesial surface with sparse setae. First segment with small spine on laterodistal margin; ventrodistal margin produced, with 1 spinule. Antennal acicle arcuate, not reaching or reaching base of cornea, terminating in slender spine, with row of sparse setae on mesial margin. Antennal flagella long, overreaching extended right cheliped.

Mandible ( Fig. 3B ) with sharp ridge on molar process. Maxillule ( Fig. 3C ) with broad proximal endite; endopod moderately broad, internal lobe slightly produced, bearing 1 apical bristle, external lobe small, basally articulated. Maxilla ( Fig. 3D ) with endopod reaching distal margin of anterior lobe of scaphognathite. First maxilliped ( Fig. 3E ) with endopod not reaching anterior margin of distal endite; exopod with lateral margin strongly expanded proximally. Second maxilliped ( Fig. 3F ) with short endopod; exopod broad. Third maxilliped ( Fig. 2D ) stout; ischium ( Fig. 2E ) with crista dentata composed of row of sharp corneous teeth and with 2 accessory teeth; merus unarmed on dorsodistal and ventromesial margins; carpus unarmed on dorsodistal margin.

Right cheliped ( Figs. 4 A-D) larger than left. Right chela subovate in dorsal view, 1.5-1.8 times longer than greatest width at base of dactylus. Dactylus subequal in length to palm; dorsal surface slightly convex, with numerous small spines or tubercles and few tufts of short setae; dorsomesial margin with single or double row of small spines (spines blunt or subacute in males, acute in females); ventral surface with tufts of short setae; in males cutting edge with row of calcareous teeth and subdistal, short row of minute corneous teeth, terminating in small calcareous claw; in females cutting edge with few low calcareous teeth on proximal 0.4 and row of small corneous teeth in distal 0.6, terminating in small corneous claw. Palm subequal in length to carpus; dorsal surface convex, with numerous, small, simple or bifid tubercles and few short setae; dorsolateral margin (including fixed finger) elevated (degree of elevation stronger in females than in males), with single row of small spines (spines blunt or subacute in males, acute in females); dorsomesial margin not elevated (males) or weakly elevated (females), with irregular single or double row of small spines; lateral face almost flat, with small, low protuberances or tubercles adjacent to dorsolateral margin and few short setae; mesial face with small tubercles (simple, bifid or multifid) adjacent to dorsomesial margin and small, low protuberances ventrally; ventral surface weakly convex, with few short setae. In males, cutting edge of fixed finger with row of calcareous teeth, distal teeth occasionally interspersed by short row of minute corneous teeth, terminating in small calcareous claw; in females, cutting edge of fixed finger with few small calcareous teeth in proximal 0.6 and row of small corneous teeth in distal 0.4, terminating in small corneous teeth. Carpus subequal in length to merus, noticeably broadened distally in dorsal view; dorsal surface with small, low tubercles or protuberances and few tufts of very short setae, dorsodistal margin with row of low, blunt teeth; dorsolateral margin not delimited; dorsomesial margin with single or double row of moderately small to large spines (proximal spines blunt); lateral face with few small, low tubercles or protuberances dorsally, ventrolateral margin smooth; mesial face almost flat, with small, low protuberances accompanied by tufts of very short setae, ventrodistal margin with row of small spines; ventral surface with small, low protuberances and few short setae. Merus with smooth dorsal surface, dorsodistal margin with few slender spines; lateral face with few small, low tubercles ventrally, ventrolateral margin slightly protuberant; mesial face smooth, ventrodistal margin with row of small spines (spines relatively larger in females than in males); ventral surface with some blister-like tubercles and tufts of short setae. Ischium unarmed on ventromesial margin; all surfaces with few short setae. Coxa with large blister-like tubercles.

Left cheliped ( Figs. 5 A-C) reaching midlength of dactylus of right cheliped. Chela 1.9-2.1 times longer than greatest width, elongate subovate l in dorsal view. Dactylus 1.5-1.7 times as long as palm; dorsal surface convex, mesially with row of small tubercles; dorsomesial margin delimited by single or double row of small spines or tubercles; mesial and ventral surface with row of tufts of short setae; cutting edge with row of small corneous teeth in distal 0.7, terminating in small corneous claw. Palm shorter than carpus; dorsal surface slightly convex, with scattered small, low, simple or bifid tubercles, and few tufts of very short setae; dorsolateral margin (including fixed finger) with single row of moderately small spines, becoming blunt and smaller proximally; dorsomesial margin with single or double row of small spines or tubercles; lateral face with small, low, bifid or multifid protuberances, and few short setae; mesial face with bifid or multifid tubercles and short setae; ventral surface weakly convex, with 2 rows of low, small protuberances extending onto fixed finger. Cutting edge of fixed finger with row of small calcareous teeth in proximal 0.7-0.8 and row of small corneous teeth in distal 0.2-0.3 (some distal calcareous teeth interspersed by short row of corneous teeth), terminating in large corneous claw. Carpus subequal in length to merus, somewhat broadened distally in dorsal view; dorsal surface with few low protuberances and short setae, dorsolateral margin not delimited; dorsomesial margin with row of spines; dorsodistal margin irregularly denticulate; lateral face with scattered very short setae, ventrolateral margin smooth; mesial face nearly flat, with few short setae, ventromesial margin smooth; ventral surface weakly convex, with few tufts of moderately long setae. Merus only with few short setae on dorsal surface; dorsodistal margin unarmed; lateral face with tiny, blister-like tubercles and few very short setae, ventrolateral margin with row of small spines or tubercles; mesial face smooth, with few very short setae, ventromesial margin slightly tuberculate; ventral surface with some blisterlike tubercles laterally and tufts of long setae. Ischium with few tiny tubercles on ventromesial margin; all surfaces with few short setae. Coxa similar to that of right.

Second and third pereopods ( Figs. 5D, F ) not overreaching right cheliped, generally similar from right to left. Dactyli 0.8-0.9 times as long as propodi, slightly curved ventrally in lateral view and nearly straight in dorsal view, terminating in large corneous claws; dorsal surfaces each with sparse short setae; lateral and mesial faces each with rows of tufts of setae dorsally and ventrally, lacking longitudinal sulcus, mesial faces ( Figs. 5E, G ) unarmed; ventral margins each with 5-7 moderately small corneous spines. Propodi distinctly longer than carpi; dorsal surfaces unarmed, with sparse row of tufts of short setae; lateral faces with few very short setae; ventral surfaces each with 3-5 corneous spinules in distal half. Carpi each with small dorsodistal spine; dorsal surfaces each with row of tufts of short setae; lateral faces convex, with row of tufts of short setae on midline; ventral surfaces each with row of short setae (setae longer and more numerous in third than in second). Meri each with row of tufts of moderately short setae on dorsal and ventral surfaces; lateral faces each with tufts of very short setae; ventrolateral distal margins concave, unarmed or occasionally armed with 1 small distal spine in second. Ischia each with sparse setae on dorsal and ventral margins. Coxae each with blister-like tubercles of various sizes. In females moderately large paired gonopores present on third pereopods.

Fourth pereopods ( Figs. 3G, J ) semichelate, notably unequal with left larger than right. Dactyli ( Figs. 3H, K ) broad, nearly straight, terminating in small corneous claw; dorsal margins each with row of tufts of setae; ventral margins each with row of small corneous teeth; preungual process arising from ventral margin between distal claw and row of corneous teeth, broad based, rounded, bearing numerous minute setules. Propodi each with long setae on dorsal surface; mesial face divided in two flattened sections by weakly elevated midline bordered by row of long setae in left ( Fig. 3I ), entirely flattened with only few setae in right ( Fig. 3K ); ventral margins convex, but in left distal 0.7 almost straight; propodal rasps each composed of single row of small corneous scales. Carpi and meri with numerous long setae on dorsal surfaces; mesial faces of carpi ventrally with row of long setae in left, without long setae in right.

Fifth pereopods chelate; in males, paired gonopores partially obscured by tufts of short setae ( Fig. 2G ).

Anterior lobe of sixth thoracic sternite ( Fig. 2F ) broadly semicircular, skewed to left; posterior lobe much broader than anterior lobe. Seventh thoracic sternite with 2 broadly separated, ovate lobes just mesial to coxae of fourth pereopods. Eighth thoracic sternite ( Fig. 2G ) with 2 subovate

lobes broadly separated and anterolaterally directed, each lobe having flattened ventral surface.

Abdomen twisted, with 3 unpaired pleopods in males, each having well-developed exopod and rudimentary endopod. Females with 4 unpaired pleopods, both rami well developed in second to fourth pleopods; fifth pereopod smaller than others, with rudimentary exopod.

Telson ( Fig. 3H ) with distinct transverse indentations. Posterior lobes slightly unequal, separated by moderately broad, deep median cleft; lateral margins convex, with few setae; terminal margins weakly convex, each with 5 or 6 prominent spines and interspersing spinules.

Coloration in life. – Generally white with black markings ( Fig. 1A ). Shield with black markings centrally. Ocular peduncles each with dark brown band proximal to midlength. Interocular lobe black or dark brown. Antennular peduncles generally white, each with black distal band on each ultimate and penultimate segments; basal segment with black band proximally. Antennal flagella banded with dark brown and white. Dactyli of chelipeds each with median black spot on dorsal surface; palms each with broad transverse band; carpus and merus with irregular black band submedially. Second and third pereopods each with irregular subproximal band and small spot on dactylus, propodus, carpus and merus.

Distribution. – Known only from Banda Islands and north of Sulawesi, Indonesia; shallow water of coral reefs.

Variation. – As is apparent from the redescription, the shape of the spines on the dorsomesial margin of the dactylus and dorsolateral margin of the palm of the right cheliped and armature of the cutting edges of the fingers of the right cheliped seem to be different between males and females. Those spines are larger and sharper in females than in males. The dorsolateral margin and dorsomesial margin of the palm of the right cheliped are more strongly elevated in females than in males. The calcareous teeth on the cutting edges are better developed in males than in females, although the rows of corneous teeth are better developed in females than in males.

Remarks. – Although Haig & Ball’s (1988) original description is detailed enough for species recognition, the following important characters, which may be useful to assess interspecific relationships, are supplemented here: the presence of blister-like tubercles or protuberances on the calcified integument of the body and appendages; the basally articulated external lobe on the endopod of the maxillule; and the noticeably dissimilar fourth pereopods. Further, the dorsal surface of the palm of the right cheliped was described as granular in the original description, although only mesial “granules” are depicted in the given illustrations (Haig & Ball, 1988, fig. 14E, F). The dorsal surface of the right palm is actually armed with numerous, small, simple or bifid tubercles.

As Haig & Ball (1988) indicated, P. moluccensis is readily distinguished from all other known species of Pagurus by the possession of a prominent, bi-spined interocular lobe. Only P. fungiformis , new species, described in this study, has a similarly bi-spined interocular lobe. Differences between the two species are discussed under “Remarks” of the latter species.

Figures

Fig. 1. A, Pagurus moluccensis Haig & Ball, 1988, live male from Marsegu Island; B, Pagurus fungiformis, new species, live male from Marsegu Island.

Fig. 2. Pagurus moluccensis Haig & Ball, 1988. A-G, holotype male from Banda Besar (sl 2.1 mm; NIOJ-A 009); H, male from Marsegu Island (sl 2.3 mm; CBM-ZC 5569). A, shield and cephalic appendages, dorsal; B, carapace, dorsal (right branchial region broken); C, ocular acicles and interocular lobe, dorsal; D, left third maxilliped, lateral; E, ischium of left third maxilliped, dorsal; F, coxae of first to third pereopods and fifth and sixth thoracic sternites, ventral; G, coxae of fifth pereopods and eighth thoracic sternite, ventral (sternite broken); H, telson, dorsal.

Fig. 3. Pagurus moluccensis Haig & Ball, 1988. A-F, male from Marsegu Island (sl 2.3 mm; CBM ZC 5569); G-K, female (sl 1.9 mm; same lot). A, left antennule, lateral; B, left mandible, dorsal; C, left maxillule, ventral; D, left maxilla, ventral (setae omitted); E, left first maxilliped, ventral; F, left second maxilliped, ventral; G, left fourth pereopod, lateral; H, dactylus of left fourth pereopod, lateral; I, dactylus and propodus of left fourth pereopod, mesial (only setae on mesial face depicted)); J, right fourth pereopod, lateral; K, dactylus and propodus of right fourth pereopod, mesial (only setae on mesial face depicted).

Fig. 4. Pagurus moluccensis Haig & Ball, 1988. A-D, holotype male from Banda Besar (sl 2.1 mm; NIOJ-A 009); E, female from Marsegu Island (sl 1.9 mm; CBM-ZC 5569). Right cheliped. A, E, chela, dorsal (setae partially omitted); B, entire right cheliped, mesial; C, same, lateral; D, carpus, dorsal.

Fig. 5. Pagurus moluccensis Haig & Ball, 1988. Holotype from Banda Besar (sl 2.1 mm; NIOJ-A 009). A, chela and carpus of left cheliped, dorsal; B, entire left cheliped, mesial; C, same, lateral; D, right second pereopod, lateral; E, dactylus of right second pereopod, mesial; F, left third pereopod, lateral; G, dactylus of left third pereopod, mesial.