Catapaguroides tuber, 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 : 182-186

Catapaguroides tuber , new species

( Figs. 25 , 26 )

Material examined. –– Holotype: male (sl 0.86 mm), PANGLAO 2004, stn B36, N of Doljo , Panglao Island, 09°35.9'N, 123°44.5'E, 23 m, reef wall, 1 Jul.2004, NMCR 39068.

Description. –– Eight pairs of biserial phyllobranchiate gills; no arthrobranchs above base of third maxilliped; 2 arthrobranchs on cheliped very small, each bilobed; remaining gills distinctly lamellate; no pleurobranchs on wall of seventh thoracic somite.

Shield ( Fig. 25A ) about 1.2 times longer than wide; anterior margins between rostrum and lateral projections slightly concave; anterolateral margins sloping; posterior margin rounded with shallow median notch; dorsal surface glabrous. Rostrum broadly triangular. Lateral projections triangular, not reaching level of rostrum, without marginal or submarginal spinule.

Ocular peduncle ( Fig. 25A ) about 0.9 length of shield, moderately slender, slightly widened proximally; dorsal surface with 2 tufts of long stiff setae in mesial distal 0.2 and 1 additional seta laterally adjacent to base of cornea; cornea artificially shrunk. Ocular acicle small, triangular, without submarginal or subterminal spinule, separated to each other basally by basal width of 1 acicle. Interocular lobe with nearly flat anterior surface.

Antennular peduncle ( Fig. 25A ) when fully extended, overreaching distal corneal margin by approximately full length of ultimate segment. Basal segment with spinule proximolaterally. Ultimate segment 0.6 length of shield, slightly broadened distally in lateral view, with 2 long plumose setae at dorsolateral distal portion. Dorsal flagellum slightly longer than ultimate peduncular segment, with distal portion about twice length of proximal aesthetasc-bearing portion.

Antennal peduncle ( Fig. 25A ) reaching corneal base. 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 short simple spine far falling short of midlength of fourth segment; dorsomesial distal angle with minute spine. First segment unarmed. Antennal acicle slender, slightly arcuate, only reaching corneal base, terminating in slender spine, with terminal tuft of setae. Antennal flagellum exceeding 3.0 length of shield, articles each with some short to long setae on distal margin (long setae present every 2 or 3 articles). Third maxilliped moderately stout, with crista dentata on ischium consisting of 2 teeth. Carpus without dorsodistal spine.

Chelipeds distinctly ( Fig. 26 ) unequal and dissimilar. Right cheliped ( Fig. 26A–C ) stout; propodal-carpal articulation rotated clockwise about 20° from perpendicular. Chela about 1.7 times longer than wide, subovate, widest at base of dactylus. Dactylus articulating obliquely with palm, subequal in length to palm, slightly curved ventrally, without conspicuous spines; dorsal surface slightly convex, with few short setae; dorsomesial margin delimited by faintly tuberculate ridge in proximal 0.6; mesial and ventral surfaces glabrous; cutting edge with 3 prominent calcareous teeth (proximalmost teeth rounded, distal two teeth triangular), terminating in tiny corneous claw. Palm subequal in length to carpus; dorsal surface slightly convex, with 2 small mesial spines located in proximal half, and low but prominent rounded protuberance at articulation with dactylus, and with few short setae; dorsolateral margin delimited by faintly tuberculate ridge; dorsomesial margins not delimited; lateral, mesial and ventral surfaces with few setae; ventral surface convex. Fixed finger with 3 unequal calcareous teeth on proximal half of cutting edge, terminating in minute corneous claw. Carpus broadened distally, about 1.3 times longer than distal width; dorsal surface with 2 moderately small lateral spines at about midlength, no mesial spine; dorsodistal margin with strong spine at lateral angle; mesial surface with few long setae dorsally; ventrolateral distal angle unarmed; ventral surface convex, with few long setae. Merus glabrous on dorsal margin; dorsodistal margin with 1 small spine mesially; lateral surface almost glabrous, ventrolateral margin generally convex, with 2 small spines subdistally; mesial surface also almost glabrous, ventromesial margin with 2 small subdistal spines; ventral surface slightly convex, with some moderately short setae. Ischium unarmed.

Left cheliped ( Fig. 26D–G ) moderately slender, slightly overreaching base of dactylus of right chela; propodalcarpal articulation rotated counterclockwise about 20° from perpendicular. Chela 2.9 times longer than wide, not arched; fingers without hiatus. Dactylus 1.1 length of palm, unarmed, with some short setae; dorsomesial margin not delimited; cutting edge microscopically denticulate, terminating in minute corneous claw. Palm about 0.6 length of carpus; dorsal surface moderately convex, spineless; dorsal and ventral surfaces with sparse long setae. Fixed finger with row of minute corneous teeth on cutting edge, terminating in minute corneous claw. Carpus slightly widened distally, about 2.7 times longer than distal width; dorsal surface with 2 mesial spines on proximal half and few tufts of long setae mesially; dorsodistal margin with 1 spine at each lateral and mesial angle; lateral and mesial surfaces almost glabrous, ventrolateral distal angle unarmed; ventral surface slightly convex, with some long setae. Merus with few short setae on dorsal margin; dorsodistal margin unarmed; lateral surface almost glabrous, ventrodistal margin with 2 small subdistal spines; mesial surface also almost glabrous, ventromesial margin generally convex, unarmed; ventral surface convex, with some long setae. Ischium unarmed.

Ambulatory legs ( Fig. 25B, D ) long and slender. Dactyli ( Fig. 25C, E ) 1.1–1.4 times longer than propodi, about 10.0–11.3 times longer than wide, straight in dorsal view, gently curved ventrally in lateral view, terminating in moderately long corneous claws; dorsal margins each with sparse short to long setae; mesial faces each with row of short sparse setae ventrally; ventral margins each with 4 or 5 slender corneous spines in distal 0.5–0.7. Propodi each with pair of slender corneous spines (second) or unarmed (third) on ventrodistal margin; dorsal and ventral margins with sparse short and long setae. Carpi without dorsodistal spine; few long setae on dorsal margin. Meri spineless; dorsal and ventral margins with few short and long setae. Ischia glabrous (second) or with few ventral setae (third). Second pereopods with shallow notch on ventral margin at articulation between merus and ischium.

Fourth pereopod ( Fig. 25F ) semichelate; dactylus with several minute corneous teeth on ventral margin; propodal rasp consisting of 6 corneous scales arranged in single row. Fifth pereopods semichelate.

Anterior lobe of sixth thoracic sternite ( Fig. 25G ) subsemicircular, bearing short setae on anterior margin.

Male with medium-sized sexual tube emanating from coxa of right fifth pereopod ( Fig. 25H ), directed from right to left, slightly curved anteriorly, distinctly overreaching lateral margin of coxa of left fifth pereopod. Coxa of left without trace of papilla-like sexual tube, but with normal opening of gonopore. Eighth thoracic sternite ( Fig. 25H ) with single broad lobe bearing numerous short setae.

Telson ( Fig. 25I ) slightly wider than long, narrowed in posterior half; no lateral indentations; posterior lobes somewhat asymmetrical, separated by small median cleft; terminal margins slightly oblique, each with 4 small spines (including spines at outer angle).

Female unknown.

Colouration. –– Not known.

Distribution. –– Known only from the type locality, 23 m.

Remarks. –– The corneas of the holotype are artificially shrunk, and thus, it is not known if the corneas are coneshaped or normally developed and rounded. Nevertheless, Catapaguroides tuber , new species, appears unique in the genus in having a prominent dorsal protuberance of the palm of the right cheliped just proximal to the base of the dactylus. The carinate mesial margin of the dactylus of the right cheliped may link this new species to C. cristimanus and C. karubar , but the slightly tuberculate margin of the mesial carina differentiates C. tuber from the latter two species. In the latter two species, the margin of the mesial dactylar carina of the right cheliped is smooth; furthermore, the carina is lamellar in C. cristimanus .

Etymology. –– From the Latin “ tuber ” [= protuberance], referring to the presence of a prominent protuberance on the right palm just proximal to the base of dactylus. Used as a noun in apposition.

Figures

Fig. 25. Catapaguroides tuber, new species, holotype, male (sl 0.86 mm), PANGLAO 2004, stn T36, NMCR 39068. A, shield and cephalic appendages, dorsal view; B, right second pereopod, lateral view; C, same, dactylus, mesial view; D, left third pereopod, lateral view; E, same, dactylus, mesial view; F, distal three segments of left fourth pereopod, lateral view; G, sixth thoracic sternite, ventral view; H, coxae of fifth pereopods and eighth thoracic sternite, ventral view; I, telson, dorsal view. Scale bars = 0.5 mm (A, B–E); 0.25 mm (F–I).

Fig. 26. Catapaguroides tuber, new species, holotype, male (sl 0.86 mm), PANGLAO 2004, stn T36, NMCR 39068. A, right cheliped, mesial view; B, same, lateral view (setae omitted); C, same, chela and carpus, dorsal view; D, left cheliped, mesial view; E, same, lateral view (setae omitted); F, same, chela, dorsal view; G, same, carpus, dorsal view. Scale bar = 0.5 mm.