Catapaguroides conicus, Komai & Rahayu, 2013

Komai, Tomoyuki & Rahayu, Dwi Listyo, 2013, The Hermit Crab Genus Catapaguroides A. Milne-Edwards & Bouvier, 1892 (Crustacea: Decapoda: Anomura: Paguridae) From The Bohol Sea, Philippines, With Descriptions Of Eight New Species, Raffles Bulletin of Zoology 61 (1), pp. 143-188 : 149-153

Catapaguroides conicus , new species

( Figs. 3–5 )

Material examined. –– Holotype: male (sl 1.0 mm), PANGLAO 2004, stn B9, Napaling , Panglao Island, 09°33.1'N, 123°44'E, 8–10 m, caves in the reef wall, 8 Jun.2004, NMCR 39062.

Paratypes: 1 ovigerous female (sl 1.0 mm), same data as holotype, MNHN; 2 females (sl 0.76, 0.92 mm) , stn B36, N of Doljo , Panglao Island, 09°35.9'N, 123°44.5'E, 23 m, reef wall, 1 Jul.2004, ZRC 2012.1092 .

Description. –– Nine pairs of biserial phyllobranchiate gills; third maxilliped with only 1 arthrobranch reduced to minute bud; two arthrobranchs on chelipeds very small, poorly lamellate; no pleurobranch on wall of seventh thoracic somite.

Shield ( Fig. 3A ) slightly wider than long or approximately as long as wide; anterior margins between rostral lobe and lateral projections concave; anterolateral margins sloping or slightly terraced; posterior margin truncate; dorsal surface almost glabrous, with few tufts of very short setae posterior to each lateral projection. Rostrum roundly triangular. Lateral projections triangular, produced to level of rostrum, each with marginal or submarginal spinule.

Ocular peduncle ( Fig. 3A ) about 0.9 length of shield, stout basally, tapering to somewhat cone-shaped cornea; dorsal surface mesially with 3 tufts of short to long setae aligned longitudinally in distal half; 1 additional tuft of setae on lateral face near base of cornea. Ocular acicle narrowly triangular, armed with tiny, subterminal spinule, separated to each other basally by basal width of 1 acicle. Interocular lobe with convex anterior surface.

Antennular peduncle ( Fig. 3A ), when fully extended, overreaching distal corneal margin by full length of ultimate segment. Basal segment with spinule proximolaterally. Ultimate segment 0.7 length of shield, slightly broadened distally in lateral view, with 2 long plumose setae on dorsolateral distal portion. Dorsal flagellum with distal portion distinctly longer than proximal aesthetasc-bearing portion.

Antennal peduncle ( Fig. 3A ) slightly falling short of or just reaching distal corneal margin. Fifth and fourth segments with few short setae. Third segment with 1 prominent spine at ventromesial distal margin. Second segment with dorsolateral distal angle produced in simple or bifid spine nearly reaching midlength of fourth segment; dorsomesial distal angle with small spine. First segment unarmed. Antennal acicle slender, arcuate, slightly falling short of or reaching to distal corneal margin, terminating in slender spinule and with tufts of long setae distally. Antennal flagellum about 4.0 times longer than shield; articles each with several short to very long setae, making flagellum considerably setose.

Third maxilliped moderately stout, with crista dentata on ischium consisting of 2 or 3 teeth. Carpus without dorsodistal spine.

Chelipeds ( Figs. 4A–D , 5A–C ) appreciably unequal and dissimilar. Right cheliped of male ( Fig. 4A–C ) large, but not particularly elongate; propodal-carpal articulation rotated clockwise about 30° from perpendicular. Chela about 1.6 times longer than wide, widest at base of dactylus. Dactylus articulating obliquely with palm, about 0.8 length of palm, somewhat curved ventrally; dorsal surface slightly convex, dorsomesial margin not delimited, armed proximally with 1 prominent protuberance terminating in small spine; cutting edge with 3 prominent, triangular calcareous teeth, terminating in tiny corneous claw; tufts of short to moderately long setae arranged in irregular longitudinal rows on surfaces. Palm 1.3 longer than carpus; dorsal surface slightly convex, with some irregular longitudinal rows of tufts of short to long setae, no spines; dorsolateral and dorsomesial margins not delimited; lateral and mesial faces also with tufts of short to long setae; ventral surface slightly convex, with tufts of long setae extending onto fixed finger. Fixed finger with 1 prominent calcareous tooth on cutting edge (tip eroded). Carpus subequal in length to merus, broadened distally, about 1.1 times longer than distal width; dorsal surface mesially with short transverse rows of short to long setae and laterally with 2 small spines around midlength, dorsodistal margin with 1 spine at mesial angle and 2 spines at lateral angle; dorsomesial margin not delimited; mesial surface dorsally with transverse tufts of long setae; lateral surface with few short setae dorsally, with 1 minute spine at ventrodistal angle; ventral surface convex, with few long setae. Merus with row of sparse short setae on dorsal surface; dorsodistal margin with 1 small spine mesially; lateral surface glabrous, ventrolateral margin nearly straight, with 2 small spines subdistally; mesial surface also glabrous, ventromesial margin with 2 small spines at distal angle; ventral surface with some long setae. Ischium unarmed, with short setae on dorsal and ventral margins.

Right cheliped of female ( Fig. 4D ) proportionally slenderer than that of male, chela elongate subovate in dorsal view; setation generally similar to that of male cheliped. Chela 2.0 times longer than wide. Dactylus with small spine on mesial surface proximally. Calcareous teeth on cutting edges of fingers weaker than those of male. Carpus also more slender than in male; spines stronger, dorsodistal medial angle with 1 strong spine.

Left cheliped ( Fig. 5A–C ) relatively slender. Chela 3.3–3.4 times longer than wide, slightly arched ventrally. Dactylus subequal in length to palm, unarmed, with scattered tufts of short to long setae; dorsomesial margin not delimited; cutting edge with row of minute corneous teeth, terminating in tiny corneous claw. Palm about 0.6 length of carpus; dorsal surface slightly convex, unarmed; surfaces with tufts of short to long setae arranged in irregular longitudinal rows. Carpus slightly widened distally, 2.7 times longer than distal width; dorsal surface unarmed, laterally with tufts of or individual long setae and mesially with 4 or 5 short transverse rows of long setae; dorsodistal margin armed with small spine each at lateral and mesial angles; lateral and mesial faces almost glabrous, ventral surface with some long setae. Merus with some tufts of moderately short setae on dorsal margin; ventrolateral margin with 1 strong spine subdistally; ventromesial margin with 1 small distal spine; ventral surface with numerous scattered long setae. Ischium spineless.

Ambulatory legs ( Fig. 5D, F ) long and slender, right second pereopod overreaching right cheliped by about half-length of dactylus. Dactyli ( Fig. 5E, G ) 1.3–1.4 times longer than propodi, 10.5–13.2 times longer than wide, straight in dorsal view, slightly curved ventrally in lateral view, terminating in long, slender corneous claws; dorsal margins each with sparse short to long setae; ventral margins each with 4–6 moderately spaced, slender corneous spines. Propodi each with pair of slender corneous spines on ventrodistal margin; dorsal and ventral margins with sparse short to long setae. Carpus with or without minute spinule at dorsodistal angle, dorsal surface with few short to long setae. Merus unarmed, with sparse short to long setae on dorsal and/or ventral margins. Ischium with few long setae on ventral margin. Second pereopods each with distinct notch on ventral margin at articulation between merus and ischium. Female with unpaired left gonopore.

Fourth pereopod ( Fig. 3B ) semichelate; dactylus with several minute corneous denticles on ventral margin; propodal rasp consisting of 7 corneous scales. Fifth pereopods semichelate.

Anterior lobe of sixth thoracic sternite ( Fig. 3C ) wide, subsemicircular, slightly skewed to left, with short setae on anterior margin.

Male with long sexual tube extending from coxa of right fifth pereopod ( Fig. 3D, E ), directed from right to left across ventral body surface and then strongly curved dorsally and anteriorly, reaching to base of left cheliped. Left coxa with short sexual tube directed anteromesially, obscured by tufts of dense setae on eighth thoracic sternite. Sternal lobe of eighth thoracic somite slightly bilobed, obscured by numerous long setae ( Fig. 3D ).

Telson ( Fig. 3F ) slightly longer than wide; no lateral indentations; posterior lobes asymmetrical, separated by shallow median cleft; terminal margins oblique, left with 2 or 3 spinules, right with 1 or 2 spinules, outer angles acutely pointed.

Eggs about 0.4 × 0.6 mm.

Variation. –– As is apparent from the above description, a notable variation is seen in the armature of the dactylus of the right cheliped. In the male holotype, the armature consists of a prominent proximal protuberance bearing a blunt spine, while there is only a small sharp spine located on the proximal 0.2 of the dactylus in the three female paratypes. It is possible that this variation might be due to sexual dimorphism.

Colouration. –– Not known.

Distribution. –– Known only from Panglao Island, the Philippines, 8– 23 m.

Remarks. –– Catapaguroides conicus , new species, appears most similar to C. foresti McLaughlin, 2002 in having the distally narrowed, cone-shaped cornea and the dorsally unarmed palm of the right cheliped. However, the new species can be readily distinguished from C. foresti by the short antennal peduncle and antennal acicle and the greatly elongate right sexual tube in male. The antennal peduncle and antennal acicle do not overreach the distal corneal margin in C. conicus , unlike distinctly overreaching it in C. foresti . The right sexual tube reaches the base of the left cheliped in C. conicus , rather than only reaching to the left coxa of the fifth pereopod in C. foresti . In addition, in C. foresti , four to eight dorsodistal marginal setae on the dactyli of the ambulatory legs become thick and bristle-like in C. foresti , but such a thickening of setae is not seen in C. conicus .

Catapaguroides hooveri McLaughlin & Pittman, 2002 , known only from the Hawaiian Islands, also resembles C. conicus in having a distally narrowed cornea and relatively short antennal peduncle and antennal acicle, but this species is immediately distinguished from the new species by the possession of a dorsomesial row of spines on the palm of each cheliped. Catapaguroides conicus has no spines on the palms of both chelipeds.

Etymology. –– From the Latin “ conicus ” [= conical], in reference to the cone-shaped cornea.

Figures

Fig. 3. Catapaguroides conicus, new species, holotype, male (sl 1.0 mm), PANGLAO 2004, stn B9, NMCR 39062. A, shield and cephalic appendages, dorsal view; B, left fourth pereopod, distal three segments, lateral view; C, sixth thoracic sternite, ventral view; D, coxae of fifth pereopods and eighth thoracic sternite, ventral view; left fifth pereopod and right sexual tube, lateral view. Scale bars = 0.5 mm (A, C–E); 0.25 mm (B, F).

Fig. 4. Catapaguroides conicus, new species. A–C, holotype, male (sl 1.0 mm), PANGLAO 2004, stn B9, NMCR 39062; D, paratype, female (sl 1.0 mm), same station, ZRC 2012.1092. A, right cheliped, mesial view; B, same, lateral view (setae omitted); C, D, same, chela and carpus, dorsal view. Scale bars = 0.5 mm.

Fig. 5. Catapaguroides conicus, new species, holotype, male (sl 1.0 mm), PANGLAO 2004, stn B9, NMCR 39062. A, left cheliped, mesial view; B, same, lateral view (setae omitted); C, same, chela and carpus, dorsal view; D, left second pereopod, lateral view; E, same, dactylus, mesial view; F, left third pereopod, lateral view; G, same, dactylus, mesial view. Scale bar = 0.5 mm.