Pagurixus paulayi, Komai & Osawa, 2006

Komai, Tomoyuki & Osawa, Masayuki, 2006, A review of the Pagurixus boninensis species group, with descriptions of six new species (Crustacea: Decapoda: Anomura: Paguridae), Zootaxa 1214 (1), pp. 1-107 : 79-85

Pagurixus paulayi n. sp.

( Figs. 33–35 , 48 )

Type material

HOLOTYPE: UF 7301 , male (SL 2.1 mm), Luminao Reef , Guam, Mariana Islands, 2.1–2.4 m, coll. F. Schroeder, 7 May 1998.

PARATYPE: UF 7302 , 1 male (SL 1.7 mm), Cocos Barrier Reef , Guam, 10–15 m, rubble field, coll. G. Paulay, 19 May 1997 .

Description

Shield ( Fig. 33A ) 1.0–1.1 times as long as broad; anterior margin between rostrum and lateral projections slightly concave; anterolateral margins sloping; dorsal surface with few tufts of short setae laterally. Rostrum triangular, not reaching level of midlength of ocular acicles, moderately broad, terminating acutely. Lateral projections slightly produced, with submarginal spinule.

Ocular peduncle ( Fig. 33A ) moderately long and stout, 0.6–0.7 length of shield, each with row of tufts of short setae on dorsal surface mesially; corneas slightly dilated, corneal width about 0.3 of peduncular length; basal part somewhat inflated, slightly broader than corneal width. Ocular acicles subtriangular, with small submarginal spine.

Antennular peduncle ( Fig. 33A, B ) overreaching distal margin of cornea by about 0.3 length of ultimate segment. Ultimate segment with tufts of long setae at dorsolateral angle; ventral surface with 2 rows of short setae directed laterally, occasionally forming indistinct tufts ( Fig. 33C ). Basal segment with small lateral spine on statocyst lobe. Ventral flagellum with numerous long setae on lateral and mesial margins.

Antennal peduncle ( Fig. 33A ) overreaching distal margin of cornea by 0.2–0.3 length of fifth segment. Second segment with very small spine at dorsomesial distal angle; laterodistal projection reaching midlength of fourth segment, terminating in simple or bifid spine. First segment with small laterodistal spine; ventromesial distal margin produced, unarmed or with spinule just lateral to antennal gland opening. Antennal acicle relatively long, arcuate, reaching or slightly overreaching distal margin of cornea; mesial margin with row of tufts of stiff setae. Flagellum moderately long, exceeding 4.0 length of shield.

Right cheliped of males ( Fig. 34A–D ) not particularly elongate, moderately stout. Chela subovate in dorsal view, 1.9–2.0 times longer than broad. Dactylus 0.7–0.8 length of palm; dorsomesial margin not delimited; surfaces with small, subacute or rounded granules; cutting edge with row of small calcareous teeth in proximal 0.7–0.8 and row of small corneous teeth in distal 0.2–0.3, terminating in small corneous claw. Palm shorter than carpus; convex dorsal surface covered with subacute or rounded granules, dorsolateral and dorsomesial margins not delimited; lateral, mesial and ventral surfaces similarly granular, and some stiff setae on mesial face. Cutting edge of fixed finger with row of low, unequal calcareous teeth (middle one largest), terminating in calcareous claw. Carpus subequal in length to merus; dorsolateral margin not delimited, dorsomesial margin weakly delimited by row of small spines increasing in size distally; all surfaces covered with subacute or rounded granules, lateral surface lacking longitudinal median ridge, ventrodistal margin weakly tuberculate; mesial face nearly smooth, with scattered long stiff setae, ventral surface moderately convex. Meral­carpal articulation lacking any pronounced clockwise rotation; dorsal surface of merus with few low transverse ridges subdistally, dorsodistal margin unarmed; lateral face with scattered very short vertical ridges, ventrolateral margin with 1 subdistal spine; mesial face smooth, with few stiff setae, ventromesial margin with row of low protuberances; ventral surface with few granules and long setae. Ischium with smooth ventromesial margin; surfaces unarmed.

Left cheliped ( Fig. 34F–H ) comparatively slender. Chela 2.7–2.8 times longer than broad. Dactylus slightly longer than palm, with tufts of short setae on surfaces (setae on ventral surface longest); dorsal surface smooth, rounded; dorsomesial margin not delimited; cutting edge with row of small corneous teeth, terminating in small corneous claw. Palm 0.5–0.6 length of carpus; dorsal surface slightly elevated in mid­line and bearing irregular longitudinal rows of small tubercles, dorsolateral and dorsomesial margins not delimited; lateral face with short oblique ridges; mesial face with few small tubercles distally; ventral surface nearly smooth; scattered tufts of long setae present on mesial and ventral surfaces. Cutting edge of fixed finger with row of small calcareous teeth, distal teeth interspersed by corneous teeth. Carpus relatively slender, 0.9–1.0 length of chela and subequal in length to merus; length about 3.1 of distal width and 2.7 of greatest height; dorsal surface with spines at dorsolateral distal and dorsomesial distal angles, dorsolateral and dorsomesial margins delimited by row of small spinulose tubercles and low protuberances; lateral face nearly perpendicular, without longitudinal median ridge; ventrolateral distal angle with spinule; sparse long setae present on mesial and ventral surfaces. Merus nearly smooth on dorsal surface, dorsodistal margin unarmed; lateral and mesial faces nearly smooth; ventrolateral margin with 3 small spines in distal half; ventromesial margin with minute spinules and very low protuberances; ventral surface with scattered long stiff setae. Ischium unarmed.

Ambulatory legs ( Fig. 35A, B ) moderately long and slender, similar from right to left. Dactyli ( Fig. 35C, D ) 0.9–1.1 length of propodi, 6.5–7.6 times longer than high, terminating in large corneous claws; dorsal surfaces each with row of sparse short setae; lateral and mesial faces each with few tufts of short setae, mesial faces unarmed (second) or armed with row of 3 or 4 corneous spinules adjacent to dorsal margin (third); ventral margins each with 8–9 long corneous spines notably increasing in size distally. Propodi not tapering distally, 5.0–6.5 times longer than high; dorsal surfaces nearly smooth, with short to moderately long stiff setae; lateral faces nearly smooth; ventral margins each with 2–4 corneous spinules, ventrodistal margins each with paired corneous spines. Carpi each with small dorsodistal spine; dorsal surfaces smooth, with row of sparse setae; lateral faces nearly smooth. Meri nearly smooth on dorsal surfaces, with sparse moderately long setae; lateral surfaces smooth; ventrolateral distal margins each with small subdistal spine (second) or unarmed (third), ventral surfaces faintly tuberculate (second) or smooth (third), all with few short setae.

Only left fourth pereopods preserved in specimens examined ( Fig. 33D, E ). Dactylus broad, terminating in tiny corneous claw; dorsal margin with numerous long setae. Propodus with slightly convex ventral margin; mesial face nearly flat, with numerous long setae dorsally, few setae ventrally. Carpus without prominent tuft setae on mesial face.

Anterior lobe of sixth thoracic sternite ( Fig. 33F ) subrectangular or subsemicircular, with anterolateral angles rounded, anterior margin with row of short setae. Eighth thoracic sternite ( Fig. 33G ) composed of two subequal, narrowly separated, rounded lobes.

Males with coxae of fifth pereopods markedly unequal ( Fig. 33G ). Right coxa with short, clearly demarcated posteromesial protrusion; setal tuft consisting of long stiff setae arising from distal margin of posteromesial protrusion and passing to left coxa. Left coxa lacking gonopore.

Telson ( Fig. 33H ) with terminal margins nearly horizontal, bearing 3 or 4 principal spines interspersed by 1 or 2 spinules.

Colour in life. Chelae and ambulatory legs generally purple (according to the field note by G. Paulay).

Distribution So far known only from Guam ( Fig. 48 ); 2.1– 15 m.

Remarks

As mentioned above, P. paulayi n. sp. is similar to P. boninensis , P. festinus and P. ruber n. sp. The spinulose right chela is characteristic for P. paulayi n. sp. Furthermore, the ventral series of setae on the ultimate antennular segment, which do not form distinct tufts, distinguishes P. paulayi from P. boninensis and P. ruber n. sp. Pagurixus paulayi differs from P. boninensis in lacking the male left gonopore and from P. ruber in the possession of a prominent ventromesial protrusion on the right coxa of the fifth pereopod in males. The general color of P. paulayi in life is purple, differing from that of P. boninensis or P.ruber .

Etymology

This species is dedicated to Dr. Gustav Paulay of the Florida Museum of Natural History, for his enormous effort to document marine biodiversity of Guam Islands.

Figures

FIGURE 33. Pagurixus paulayi n. sp. Holotype male (SL 2.1 mm) from Guam (UF 7301). A, shield and cephalic appendages, dorsal view; B, left antennule, lateral view; C, ultimate segment of left antennular peduncle, ventral view; D, left fourth pereopod, dactylus and propodus, lateral view; E, same, mesial view; F, sixth thoracic sternite, ventral view (damaged); G, coxae of fifth pereopods and eighth thoracic sternite, ventral view; H, telson, dorsal view. Scale bars: 0.5 mm.

FIGURE 34. Pagurixus paulayi n. sp. Holotype male (SL 2.1 mm) from Guam (UF 7301). A, chela of right cheliped, dorsal view; B, entire right cheliped, mesial view; C, same, lateral view; D, carpus of right cheliped, dorsal view; E, chela of left cheliped, dorsal view; F, entire left cheliped, mesial view, G, same, lateral view; H, carpus of left cheliped, dorsal view. Scale bar: 0.5 mm.

FIGURE 35. Pagurixus paulayi n. sp. Holotype male (SL 2.1 mm) from Guam (UF 7301). A, right second pereopod, lateral view; B, left third pereopod, lateral view; C, right second pereopod, dactylus and distal part of propodus, mesial view; D, left third pereopod, dactylus and distal part of propodus, mesial view. Scale bars: 0.5 mm.

FIGURE 48. Geographic distribution of Pagurixus boninensis (), P. festinus (), P. brachydactylus n. sp. (), P. carinimanus n. sp. (), P. paulayi n. sp. (Π), P. pseliophorus n. sp ()., and P. ruber n. sp. ().