Pseudopaguristes mclaughlinae, Rahayu, 2008

Rahayu, Dwi Listyo, 2008, The genus Pseudopaguristes McLaughlin (Crustacea: Decapoda: Anomura: Diogenidae) from the southwestern Pacific, with the descriptions of two new species, Zootaxa 1840, pp. 54-66 : 56-59

Pseudopaguristes mclaughlinae n. sp.

( Figs. 1–2)

Material examined. HOLOTYPE: New Caledonia, Bathus 3 : Holotype, male, 2.4 mm, stn. DW 838, 23º00.81'S, 166º55.87'E, 400–402m, 30 Nov 1993 ( MNHN) . PARATYPES: 10 males, 2.2–3.2 mm, 3 females ovig., 1.9–2.7 mm, 3 females 2.0– 2.9 mm, same locality as holotype ( MNHN). Musorstom 4 : 1 male, 2.0 mm, stn. CP169, 18º54'S, 163º11.2'E, 590 m, 17 Sep 2005. Volsmar: 1 female ovig., 2.5 mm, stn. DW 38, 3 Jun 1989, 420 m ( MNHN) .

Wallis Island, Musorstom 7: 1 male, 3.0 mm, stn. DW 525, 13º11'S, 176º15'E 13 May 1992, 500– 600 m ( MNHN) . Vanuatu, Musorstom 8: 1 female, 2.0 mm, 1 female ovig., 1.6 mm, stn. DW 960, 20º20.10'S, 169º49.90'E, 390–422 m, 20 Sept 1994; 1 male, 2.0 mm, stn. CP 983, 19º21.61'S, 169º27.76'E, 480– 475 m, 23 Oct 1994; 1 male, 2.0 mm, female, 1.5 mm, stn. CP 984, 11º47'S, 178º19'E, 480–544m, 23 Sep 1994; 1 male, 2.5 mm, 2 females ovig., 2.3, 2.5 mm, stn. DW 1060, 16º13.82'S, 167º20.80'E, 397– 375 m, 2 Oct 1994; 1 female ovig., 2.0 mm, stn. DW 1064, 16º16.02'S, 167º20.55'E, 459 m, 2 Oct 1994; 1 female ovig., 2.0 mm, stn.DW 1065, 16º16.12'S, 167º21.43'E, 360–419 m, 2 Oct 1994; 2 males, 1.7, 1.8 mm, stn. DW 1108, 15º04.88'S, 167º15.25'E, 405–419 m, 7 Oct 1994 ( MNHN) . Loyalty Island , Musorstom 6 : 1 female 3.0 mm, stn. DW 428, 20º23.54'S, 166º12.57'E, 420 m, 17 Feb 1989; 1 female, 2.9 mm, stn. CP 467, 21º05.13'S, 167º32.11'E, 575 m, 21 Feb 1989; 1 male, 2.5 mm, 1 female, 1.9 mm, stn. DW 485, 21º34.48'S, 167º59.33'E, 575 m, 21 Feb 1989 ( MNHN) ; 7 males, 1.5–2.5 mm, 2 females ovig. 1.9, 1.9 mm, stn. DW 459, 21º01.39'S, 167º31.47'E, 425 m, 20 Feb 1989 ( MZB) ; 3 males, 2.0 – 2.5 mm, 2 females, 2.0, 2.4 mm, stn. CP 464, 21º02.30'S, 167º31.60'E, 430 m, 21 Feb 1989 ( MZB) . Chesterfield Islands , Ebisco : 1 female 2.0 mm, stn DW 2526, 22º46'S, 159º23'E, 330–340 m, 9 Oct 2005; 1 male, 1.9 mm, 1 female ovig., 1.9 mm, stn. DW 2555, 21º4'S, 158º35'E, 500–614m, 12 Oct 2005; 15 males, 1.5–2.5 mm, 3 females, 1.2–1.6 mm, 2 females ovig. 1.9, 2 mm, stn. DW 2617, 21º06'S, 160º22.60'E, 427–505m, 20 Oct 2005; 7 males 1.1–2.7, 3 females ovig. 1.7–2.0 mm, stn. DW 2619, 20º6'S, 160º23'E, 490–550 m, 20 Oct 2005; 2 males, 2.0, 2.3 mm, stn. DW 2620, 20º06'S, 160º22'E, 532–623m, 20 Oct 2005; 1 male, 1.9 mm, 2 females, 2.0, 0.2 mm, stn. DW 2625, 20º05'S, 160º19'E, 627–714m, 20 Oct 2005; 1 male, 2.7 mm, stn. DW 2626, 21º6'S, 160º49'E, 728–739m, 21 Oct 2005 ( MNHN) ; 1 male, 2.5 mm, stn. DW 2576, 20º20'S, 158º43'E, 390–394m, 14 Oct 2005 ( MZB) .

Description. Gills biserial; branchiostegites each with row of small spinules on dorsal margin distally, anterior margins each with 1 or 2 spinules or very small spines.

Shield ( Fig. 1A) slightly longer than broad; anterolateral margins sloping; anterior margin between rostrum and lateral projections concave; posterior margin truncate; several spines and sparse setae on dorsolateral surface and lateral margin. Lateral projections triangular, with or without terminal spinule. Rostrum obtusely triangular, reaching beyond bases of ocular acicles, with terminal spinule and with moderately long setae marginally.

Ocular peduncles, 0.5–0.7 length of shield; dorsal surfaces each with sparse row of moderately long setae; corneal diameter 0.2–0.3 of peduncular length. Ocular acicles acutely triangular, each with small terminal spine; separated basally by approximately basal width of 1 acicle.

Antennular peduncles, when fully extended, exceeding distal corneal margins by 0.5 length of ultimate peduncular segments. Ultimate segment with few short setae, penultimate segment with small spine on ventral surface at approximately midlength. Basal segment with acute spine on dorsolateral margin of statocyst lobe and 1 spine at ventromesial distal angle.

Antennal peduncles reaching bases of corneas; fifth segment unarmed; fourth segment with small dorsodistal spine; third segment with ventromesial distal angle prominently produced, terminating in acute spine; second segment with dorsolateral distal angle produced, terminating in bifid spine; dorsomesial distal angle with small spine; first segment unarmed. Antennal acicles each reaching to or slightly beyond midlength of fifth peduncular segment, with bifid terminal spine; mesial margin with 3 or 4 spines, lateral margin with 2 spines in distal half. Antennal flagellum much shorter than carapace; each article with 2-4 long and moderately short setae.

Coxae of third maxillipeds each with 2 or 3 small spines on ventromesial margins; ischia each with well developed crista dentata and 1 small spine on ventrodistal margin; meri each with 3 spines on ventral margin.

Chelipeds subequal ( Fig. 1B), armature generally similar; dactyl and fixed finger with narrow hiatus. Dactyl 1.5 longer than palm; dorsomesial margin with row of moderately large corneous-tipped spines, decreasing in size distally and accompanied by tufts of long setae, dorsal surface with row of 2 or 3 spines distally and tufts of setae; mesial face ( Fig. 1C) with ventroproximal and dorsodistal unarmed areas, remainder of surface with irregular rows of small, sometimes corneous-capped tubercles and small spines, ventral margin with few protuberances and tufts of setae; cutting edge with row of moderately large calcareous teeth in proximal 0.7, row of corneous teeth distally; terminating in small corneous claw, slightly overlapped by fixed finger. Palm 0.7 length of carpus; dorsomesial margin with row of 3 prominent corneous-tipped spines and tufts of setae, dorsolateral margin with row of prominent spines continued to fixed finger; weakly convex dorsal surface with 2 or 3 irregular rows of moderately large, sometimes corneous-tipped spines, each accompanied by tufts of long setae, few rows extending entire length of fixed finger; mesial face with few small tubercles; ventral surface with few tubercles and sparse tufts of long setae, tubercles most prominent on palm; cutting edge of fixed finger with row of moderately large calcareous teeth; terminating in large corneous claw. Carpus 0.8 length of merus; dorsomesial margin with row of 4 prominent, corneous-tipped spines, dorsal surface with median row of corneous-tipped spines accompanied by tufts of long setae, dorsolateral margin delimited by row of prominent, corneous-tipped spines; lateral face with few tubercles and tufts of setae; mesial face with few tufts of setae. Merus with few spines on distal margin; dorsal margin with short row of transverse, spinose or spinulose ridges accompanied by tufts of long setae; ventromesial and ventrolateral margins each with row of small corneous-tipped spines and long setae. Ischium with row of minute tubercles on ventromesial margin.

Second ( Fig. 2A, B) and third pereopods ( Fig. 2C, D) with dactyls 1.3 length of propodi; dorsal margins each with row of tufts of moderately long, stiff setae, few very small spines on second pereopods; lateral faces each with row of tufts of short setae dorsally; mesial faces each with median row of short setae, irregular row of tiny spinules medially on third pereopods; ventral margins each with row of 8 or 9 widely-spaced, corneous spines. Propodi 1.2 length of carpi; dorsal margins each with row of spines accompanied by tufts of moderately long setae on second pereopods, third with row of tufts of moderately long setae; mesial faces each with few small spines and 2 irregular rows of short setae on second pereopods, third with median row of small spines accompanied by moderately long setae; lateral surfaces each with dorsal row of tufts of setae; ventral surfaces each with row of small spinules and sparse tufts of setae on second pereopods, third only with sparse tufts of setae. Carpi 0.8 length of meri; dorsal margins each with irregular row of moderately large spines on second pereopods or dorsodistal spine on third; lateral faces each with weak longitudinal sulcus and small spine dorsally on second pereopods; ventral surfaces each with few tufts of short setae. Meri each with dorsal row of small spinules on third pereopods, only proximally on second, and tufts of moderately short setae; ventral margins of second pereopods each with row of small spines in distal half and tufts of moderately short setae, third unarmed but with sparse tufts of setae. Ischia unarmed but with sparse setae. Fourth pereopods ( Fig. 2E) each with small preungual process at base of claw, carpi each with distal spine on dorsal margin.

Male first pleopods ( Fig.1D, E) each with row of moderately short setae on lateral margin of inferior lamella, row of hooked spines on distal margin; external lobe overreaching distal margin of inferior lamella; internal lobe short, with long marginal setae. Basal segment of second pleopods ( Fig. 1F, G) with few setae, distal segment with sparse setae distally on endopod, appendix masculina with row of long marginal setae. Female gonopores paired. Brood pouch ( Fig. 2G) subovate, with marginal plumose setae. Tergites of left pleonal somites 2–4 each with thickened margin and row of long, moderately dense, plumose setae. Eggs attached to pleopods 2 and 3, not shielded by brood pouch; non-eyed eggs 1 mm diameter.

Telson ( Fig. 2F) with deep lateral incisions separating anterior and posterior lobes; asymmetrical posterior lobes separated by V-shaped median cleft; left lobe slightly larger, both lobes with prominent terminal spines and sparse long setae.

Color. After long preservation in alcohol the only remaining color is orange on the ocular peduncles and penultimate segments of the antennular peduncles.

Etymology. This species is dedicated to Dr. Patsy A. McLaughlin who described the genus Pseudopaguristes .

Distribution. Wallis, Vanuatu, New Caledonia, Loyalty, and Chesterfield Islands, 375– 739 m.

Remarks. In having antennal peduncles longer than ocular and antennular peduncles, and long and slen- der second and third pereopods with sparse setae, Pseudopaguristes mclaughlinae n. sp. closely resembles P. laurentae . However, P. laurentae is easily distinguished by the presence of a long and large spine on the ventral margin of the fourth segment of each antennal peduncle, which is absent in P. mclaughlinae . The new species is also different in having tuberculate or corneous-tipped spines that cover the mesial surfaces of dactyls of the chelipeds. Although this character is shared with P. hians ( Henderson, 1888) and P. asper Rahayu, 2005 , P. hians is recognizable by the reduction of male first pleopod, the absence of second male pleopod, and the presence of female gonopore only on the coxa of left third pereopod, while in P. mclaughlinae the first and second male pleopods, and female gonopores are paired. Pseudopaguristes asper is characterized by the spiniform bristles or very slender spines on the terminal margin of the telson, whereas the telson of P. mclauglinae has a row of prominent spines on its terminal margin.