Pagurixus spiniferore, Komai & Rahayu, 2013

Komai, Tomoyuki & Rahayu, Dwi Listyo, 2013, Records Of The Hermit Crab Genus Pagurixus Melin, 1939 (Decapoda: Anomura: Paguridae) From Shallow Coral Reefs In The Panglao Islands, The Philippines, With Description Of A New Species, Raffles Bulletin of Zoology 61 (1), pp. 133-141 : 136-140

Pagurixus spiniferore , new species

( Figs. 2–4 )

Material examined. — Holotype: PANGLAO 2004, stn B23, Balicasag , Black Forest, 09°31.1'N, 123°41.3'E, 20–25 m, rubble on sand, male (sl 1.4 mm), NMCR 39060.

Description. — Shield ( Fig. 2A ) about 1.2 times longer than wide; anterior margin between rostrum and lateral projections slightly concave; anterolateral margins sloping; dorsal surface slightly convex, with few short setae. Rostrum triangular,

moderately produced, terminating subacutely. Lateral projections obsolete, each with submarginal spinule.

Ocular peduncles ( Fig. 2A ) moderately long and stout, about 0.7 length of shield, with 3 tufts of short stiff setae on dorsal surface mesially and 1 stiff setae located at midlength of mesial face; cornea slightly dilated, corneal diameter about 0.4 of peduncular length; basal part slightly inflated, narrower than cornea. Ocular acicles, subtriangular, each with submarginal spinule.

Antennular peduncles ( Fig. 2A, B ) moderately stout, overreaching distal corneal margins by about 0.3 lengths of ultimate segments. Ultimate segment 3.1 times longer than high, with short individual seta on dorsolateral distal portion; ventral surface glabrous. Basal segment with small laterodistal spine on statocyst lobe. Ventral flagellum with row of sparse setae on lateral and mesial margins.

Antennal peduncles ( Fig. 2A ) overreaching distal corneal margins by about 0.1 length of fifth segment. Third segment with small spine at ventromesial distal angle. Second segment with spinule at dorsomesial distal angle; laterodistal projection reaching nearly midlength of fourth segment, terminating in simple spine. First segment with laterodistal spinule; ventromesial distal margin with small projection. Antennal acicle moderately long, faintly arcuate, slightly overreaching base of cornea, terminating in spinule obscured by tuft of stiff setae; mesial margin with few tufts of stiff setae. Antennal flagellum broken.

Male right cheliped ( Fig. 3A–C ) moderately stout, not particularly elongate. Chela about 2.2 times longer than wide. Dactylus subequal in length to palm measured along mesial margin, terminating in small calcareous claw; dorsomesial or mesial margin not delimited; slightly rounded dorsal surface without conspicuous spines or tubercles, ventral surface nearly smooth; cutting edge with two obtuse calcareous tooth in proximal half and row of minute, blunt teeth in distal half. Palm slightly widened distally, subequal in length to carpus; dorsal surface convex, with some small to tiny spines (proximal spine on midline conspicuous); dorsolateral margin delimited by row of small spines extending onto fixed finger and decreasing in size distally; dorsomesial margin also with row of small spines or spiniform tubercles, also decreasing in size distally; lateral and mesial faces almost glabrous; ventral surface also smooth, slightly convex, with few short setae. Fixed finger terminating in calcareous claw; cutting edge with row of small, rounded teeth. Carpus subequal in length to merus, length about 1.4 of distal width; dorsal surface with irregular rows of small spines (dorsodistal spine prominent) and moderately short stiff setae dorsomesially and few tiny spinulose tubercles and short spiniform setae dorsolaterally; dorsodistal margin with 3 small acute spines lateral to midpoint; lateral surface without trace of division; ventral surface convex, no prominent setae on distal margin; ventrodistal margin unarmed. Meral-carpal articulation lacking any pronounced clockwise rotation. Meral surfaces almost glabrous; dorsodistal margin with some spiniform setae; ventrolateral margin with trace of granules distally; ventromesial margin with row of 4 small spines in distal half; ventral surface smooth, with few setae. Ischium with smooth ventromesial margin; surfaces smooth.

Left cheliped ( Fig. 3E–H ) moderately short, stout. Chela about 2.8 times longer than wide, about 1.2 times longer than carpus. Dactylus longer than palm, terminating in small corneous claw, with tufts of stiff setae on surfaces arranged in longitudinal rows; dorsal surface rounded, smooth; cutting edge with row of small corneous teeth. Palm about half length of carpus; dorsal surface with row of tiny spines on elevated midline, and with one more row of spinules proximal to base of dactylus; dorsolateral and dorsomesial margins not delimited; lateral surface with scattered low granules; mesial and ventral surfaces smooth; scattered tufts of setae on ventral surface (including fixed finger). Fixed finger terminating in small corneous claw, cutting edge with row of small corneous teeth. Carpus somewhat compressed laterally, subequal in length to merus; length 2.4 of distal width and 2.1 of height; dorsolateral margin with 2 small spines in distal half and few low protuberances bearing stiff setae in proximal half, dorsomesial margin with row of 3 small spines in distal half and few low protuberances bearing stiff setae in proximal half; dorsodistal margin with 2 spines; lateral surface nearly perpendicular, without trace of division, nearly smooth, ventrolateral margin with 1 small spine and low, obtuse protuberances; mesial surface with few low protuberances dorsally, otherwise nearly smooth, ventrodistal margin unarmed; ventral surface convex, with several long setae. Merus glabrous on dorsal surface, dorsodistal margin unarmed; lateral surface almost smooth, ventrolateral margin with row of 4 small spines distally; mesial face also smooth, ventromesial margin minutely denticulate; ventral surface weakly convex, smooth, with few setae. Ischium unarmed.

Ambulatory legs ( Fig. 4A, D ) moderately stout, similar on right and left. Dactyli ( Fig. 4B, E ) about 0.9–1.0 times as long as propodi, 6.2–6.7 times longer than wide, terminating in large corneous claws; dorsal surfaces with sparse short setae; lateral and mesial faces smooth; ventral margins each with 6 or 7 moderately long corneous spines increasing in size distally. Propodi not tapering distally, 4.4–4.8 times longer than wide; dorsal surfaces with sparse tufts of moderately long setae; lateral and mesial faces smooth; ventral margins each with 1 or 2 minute corneous spinules, ventrodistal margins each with single or paired small corneous spines. Carpi each with small dorsodistal spine, dorsal surfaces each with low protuberance at about proximal one-third (second; Fig. 4C ), or nearly smooth (third; Fig. 4F ). Meri with sparse setae on smooth dorsal and ventral margins; lateral surfaces nearly smooth; ventrolateral distal margins each with one small spine (second) or unarmed (third).

Fourth pereopods ( Fig. 2C ) subequal and similar. Dactyli moderately broad, straight, terminating in small corneous claw, with tuft of short setae distally. Propodi with sparse setae on dorsal margins; mesial faces nearly flat or slightly convex, with few short setae; propodal rasp of single row of corneous scales. Carpi without prominent tufts of setae on mesial faces.

Coxae of fifth pereopods slightly unequal in male ( Fig. 2E ); right coxa with prominent tuft of setae overreaching lateral margin of left coxa; no development of posteromesial protrusion apparent; papilla-like protrusion of vas deferens present. Left coxa with gonopore mesially encircled by short setae; papilla-like protrusion of vas deference seen.

Anterior lobe of sixth thoracic sternite ( Fig. 2D ) roundly subrectangular, slightly skewed, with row of short to long setae on anterior margin. Eighth thoracic sternite ( Fig. 2E ) composed of two distinctly unequal, closely set, rounded lobes; each lobe bearing some short setae laterally to anteriorly.

Telson ( Fig. 2F ) with terminal margins oblique, with 3 (left) or 4 (right) spinules.

Colouration in life. — Not known.

Distribution. — So far known only from the type locality, Balicasag, Bohol, the Philippines, 20– 25 m.

Remarks. — Pagurixus spiniferore , new species, is referred to the P. anceps species group because of the absence of setal rows on the ventral surface of the ultimate segment of the antennular peduncle. Currently, the following 15 species is known in this informal species group: P. acanthocarpus Komai & Okuno, 2009 , P. amsa Morgan, 1993 , P. anceps , P. aurantiaca Komai, 2010 , P. dissimilis Osawa & Komai, 2007 , P. fasciatus Komai & Myorin, 2005 , P. hectori ( Filhol, 1883) , P. haigae Komai & Osawa, 2007 , P. handrecki Gunn & Morgan, 1992 , P. jerviensis McLaughlin & Haig, 1984 , P. kermadescensis de Saint Laurent & McLaughlin, 2000 , P. longipes , P. nanus Komai & Takada, 2006 , P. patiae Komai, 2006 , and P. stenops Morgan, 1993 . When male is concerned, the new species is immediately distinguished from these 15 species by the armature of the right cheliped. In P. spiniferore , the dorsolateral and dorsomesial margins of the palm bear a row of small spines or spiniform tubercles respectively; the palm is armed with a conspicuous proximal spine on the midline. In other species, the dorsolateral and dorsomesial margins of the palm of the right cheliped are not delimited or are carinate at most. Furthermore, the presence of spines on the dorsodistal margin of the carpus of the right cheliped differentiates the new species from all but P. handrecki . The carpus of the second pereopod bears a low protuberance on the dorsal margin proximal to the midlength in the new species. In all but P. acanthocarpus , P. aurantiaca , P. dissimilis and P. nanus , the carpus of the second pereopod is unarmed on the dorsal margin. In P. acanthocarpus , the carpus of the second pereopod bears usually a row of small spines other than the dorsodistal spine; in P. aurantiaca , P. dissimilis and P. nanus , there is one tiny spine on the dorsal margin of the carpus of the second pereopod located proximal to the midlength.

Etymology. — From the combination of the Latin, spinifer (= spinous) and ore (edge), referring to the spinose dorsolateral and dorsomesial margins of the right chela in this new species. Used as a noun in apposition.

Figures

Fig. 2. Pagurixus spiniferore, new species, male (sl 1.4 mm), holotype, NMCR 39060, PANGLAO 2004, stn 23. A, shield and cephalic appendages, dorsal view; B, ultimate segment and flagella of left antennule, lateral view; C, left fourth pereopod, lateral view; D, sixth thoracic sternite, ventral view; E, eighth thoracic sternite and coxae of fifth pereopods, ventral view; F, telson, dorsal view. Scale bars = 0.5 mm.

Fig. 3. Pagurixus spiniferore, new species, male (sl 1.4 mm), holotype, NMCR 39060, PANGLAO 2004, stn 23. A, right chela, dorsal view; B, right cheliped, mesial view; C, same, lateral view; D, same, carpus, dorsal view; E, left chela, dorsal view; F, left cheliped, mesial view; G, same, lateral view; H, same, carpus, dorsal view. Scale bar = 0.5 mm.

Fig. 4. Pagurixus spiniferore, new species, male (sl 1.4 mm), holotype, NMCR 39060, PANGLAO 2004, stn 23. A, right second pereopod, lateral view; B, same, dactylus, mesial view; C, same, carpus, mesial view; D, left third pereopod, lateral view; E, same, dactylus, mesial view; F, same, carpus, mesial view. Scale bars = 0.5 mm.