Pseudopaguristes asper, Rahayu, Dwi Listyo, 2005

Rahayu, Dwi Listyo, 2005, Additions to the Indonesian fauna of the hermit crab genus Pseudopaguristes McLaughlin and a further division of the genus Paguristes Dana (Crustacea: Decapoda: Paguroidea: Diogenidae), Zootaxa 831, pp. 1-42 : 34-38

Pseudopaguristes asper n. sp. ( Figs. 13 , 14 )

Material examined. Holotype: male 6.0 mm, Siboga , stn. 12, 07°15'S, 115°15.6'E, 289 m, 14 Mar 1899 ( ZMA). Paratypes: 3 females 3.4–5.5 mm, same locality as holotype ( ZMA); 1 ovig.female 3.0 mm, Th. Mortensen Expedition 1899­1930, stn. 15, 7°29'S, 114°49'E, 240 m, 10 Apr 1929 ( ZMUC).

Description. Biserial phyllobranchiae. Shield ( Fig. 13 a) slightly longer than broad; dorsal surface with few spinules laterally, lateral margins sloping. Rostrum broadly triangular, weakly projecting with obtuse apex, not overreaching bases of ocular acicles. Lateral projections longer than rostrum, triangular, terminating in1 or 2 acute spines. Ocular peduncles long and slender, 0.7–0.8 length of shield, weakly inflated proximally; corneas not dilated, diameter 0.1–0.2 of peduncular length. Ocular acicles moderately large, subquadrate, with 5–6 terminal spines or spinules, long plumose setae at apices. Antennular peduncles exceeding ocular peduncles by half length of ultimate segment. Mesial and lateral margins of proximal segments each with strong distal spine, weaker median spine on lateral margin. Antennal peduncles reaching 0.7–0.8 length of ocular peduncles. Fifth and fourth segments unarmed; third segment strongly projecting ventrally, armed with 3 strong distal spines; second segment with dorsolateral distal angle produced, terminating in prominent simple or bifid spine, dorsomesial distal angle weakly produced, subdistal spine on lateral or dorsal margins; first segment with small spine on lateral margin. Antennal acicles large, reaching approximately 0.7 of fifth segment; with bifid terminal spine, mesial margin with 5–6 spines, lateral margin with 2 larger spines. Antennal flagellum moderately short, about the same length as shield, consisting of about 20 articles; each article with short, sparse setae.

Third maxilliped with 2 strong spines and 1 smaller spine on ventrodistal margin of ischium; ventral margin of merus with 6 spines; carpus, propodus and dactyl unarmed.

Chelipeds ( Fig. 14 a–c) subequal, armature generally similar. Coxae each with row of small spines on ventromesial margin. Dorsal margins of meri each with row of spines, stronger distally, subdistal transverse row of spines extending mesially and laterally; lateral faces each with sparse tubercles, mesial faces smooth; ventromesial and ventrolateral margins each with row of spines and plumose setae. Carpi slightly more than half length of meri; dorsomesial margins each with 5 strong, blunt spines, dorsal surface near dorsomesial margin with strong subdistal spine followed by row of small tubercles and tuft of stiff setae, second row of small tubercles medially obscured by tufts of stiff setae. Palms approximately same length as carpi; dorsomesial margins each with 5 large spines; dorsal surfaces with more or less longitudinal rows of small tuberculate spines, becoming larger and closely­spaced on fixed fingers; tuft of long and short stiff setae on each tubercles; mesial surfaces with few small tubercles. Cutting edges of fixed fingers each with large teeth, terminating in corneous claws. Dactyls approximately same length as palms; dorsomesial margins each with rows of strong spines and few sparse tufts of setae, dorsal surface with few strong, blunt spines, few sparse tufts of long setae proximally and tufts of short setae distally; mesial surfaces covered with small conical, corneous­tipped tubercles and few tufts of setae; cutting edge with row of large calcareous teeth, terminating in rather long corneous claw, dactyl and fixed finger with distinct hiatus

Second and third pereopods slightly longer than chelipeds; similar from left to right. Meri of second pereopods ( Fig. 14 d) with ventral margins each bearing small spines distally. Carpi with 7 (left) or 8 (right) irregular spines on dorsal margins, 1 spine located dorsomesially. Propodi considerably longer than carpi, each with row of 7 (left) or 8 (right) strong spines and tufts of long setae on dorsal margin subdistally; ventral margins each with row of spinules and tufts of setae; lateral faces with longitudinal row of setae medially, mesial faces with scattered tufts of setae. Dactyls 1.3 length of propodi, each terminating in strong corneous claw; dorsal margins each with double rows of long setae; ventral margins each with row of corneous spines and long setae; lateral faces with tufts of setae on distal halves; mesial faces with tuft setae on proximal halves.

Meri of third pereopods ( Figs. 14 e, f) with dorsal margins each bearing row of spines and long plumose setae, ventral margins each with long plumose setae. Carpi 0.9 length of meri, each with strong subdistal spine on dorsal margin, long setae on dorsal margin and tuft of setae on lateral surface medially. Propodi considerably longer than carpi, dorsal margins with double rows of setae, lateral faces with tufts of setae medially, ventral margins with long setae. Dactyls 1.4 length of propodi, each terminating in strong corneous claw; dorsal margins each with double rows of long setae; ventral margins each with row of corneous spines and long setae. Fourth pereopod ( Fig. 13 b) without preungual process. Male first pleopods robust ( Figs. 13 d, e); inferior lamella elongate, distal margin rounded with curved lobe. External lobe slightly curved at tip, separated from internal lobe by deep narrow cleft; internal lobe broadly elongate. Unpaired left pleopods 3 to 5 uniramous. Female with single left gonopore, brood pouch large.

Telson ( Fig. 13 c) subquadrate, left and right lobe about same length, separated by shallow, wide V shaped median cleft; each lobe armed with spiniform setae on terminal margin, not extending onto lateral margin.

Etymology. From latin asper meaning rough, reflecting the surfaces of pereopods that are spinulose and rough.

Habitat. Collected from sand, mud and shell fragment substrate.

Distribution. Bali Sea, Indonesia.

Remarks. The females examined are smaller than the male holotype. Several, possibly size­related differences, such as stouter ocular peduncles with slightly convex lateral margins, and the denser, longer setae on chelipeds and pereopods.

The telson and the first male pleopods of this species are remarkably distinctive: the posterior lobes of the telson are subquadrate and separated from each other by wide, shallow Vshaped median cleft, the terminal margins each are armed with spiniform setae. The distal margin of the inferior lamella of the first male pleopod forms a lobe that curves toward exterior instead of having the usual hook­like spines. These two characters will easily separate P. a s p e r from its congeners.

Figures

FIGURE 13. Pseudopaguristes asper n. sp., holotype, male 6.0 mm (ZMA): a. shield and cephalic appendages, setae omitted; b, left fourth pereopod, setae omitted; c, telson; d, e, right male first pleopod; d, external view; e, internal view. Scales equal 1 mm.

FIGURE 14. Pseudopaguristes asper n. sp., holotype, male 6.0 mm (ZMA): a – c, left cheliped, setae omitted; d, left second pereopod, setae omitted; e, f, left third pereopod, setae partially omitted; a, d, f, mesial view; b, dorsal view; c, merus (lateral view); e, lateral view. Scales equal 1 mm.