Lithopagurus boucheti, Mclaughlin & Lemaitre, 2004

Mclaughlin, Patsy A. & Lemaitre, Rafael, 2004, The discovery of two new species of Lithopagurus Provenzano, 1968 (Crustacea, Decapoda, Anomura, Paguroidea, Paguridae) and the first records of the genus in the western Pacific, Zoosystema 26 (3), pp. 483-494 : 487-490

Lithopagurus boucheti n. sp.

( Fig. 2 )

TYPE MATERIAL. — Fiji. BORDAU 1, stn DW 1486, 19°01’S, 178°26’W, 385-540 m, 10.III.1999, holotype 2.0 mm (MNHN-Pg 7079).

ETYMOLOGY. — This species is dedicated to Philippe Bouchet (MNHN) whose enthusiasm for exploring the mysteries of the western Pacific marine environment is inspirational.

TYPE LOCALITY. — Fiji, 19°01’S, 178°26’W, 385- 540 m. DISTRIBUTION. — Known only from the type locality.

DESCRIPTION

Shield ( Fig. 2A, B ) somewhat vaulted; as broad as long; anterior margin between rostrum and lateral projections concave; anterolateral margins sloping, each with posterolaterally directed slender spine; posterior margin roundly truncate; dorsal surface well calcified, glabrous. Rostrum as broadly subtriangular lobe with prominent supramarginal spine produced well beyond level of lateral projections. Lateral projections weakly developed, broadly subtriangular, each with small marginal spine.

Ocular peduncles 0.6 shield length, swollen in proximal half, each with row of sparse tufts of setae dorsomesially; corneal diameter approximately 0.3 of peduncular length. Ocular acicles moderately small, narrowly triangular, each with prominent terminal spine; separated basally by more than basal width of one acicle.

Antennular peduncles overreaching distal margins of corneas by entire length of ultimate peduncular segments. Segments all with scattered short setae, basal segment also with small spine on dorsolateral margin.

Antennal peduncles overreaching distal corneal margins by approximately 0.5 length of fifth segments. Fifth and fourth segments each with few scattered setae. Third segment with small spine at ventrodistal angle. Second segment with dorsolateral distal angle produced, terminating in small bifid spine, also with small subdistal spine; dorsomesial distal angle with small spine. First segment with prominent spine on laterodistal margin, small spine laterally on produced ventral margin. Antennal acicles reaching to or slightly beyond proximal margins of fifth peduncular segments; terminating in simple or bifid spine and with few moderately long setae. Antennal flagella reaching full length of right cheliped; each article with irregularly set, short to moderately long (1 or 2 article-length) setae.

Right cheliped ( Fig. 2C ) very much larger than left, semioperculate. Dactyl approximately 0.8 length of palm; cutting edge with row of moderately large, calcareous teeth, terminating in small corneous claw; dorsal surface flat, with numerous long setae and small tubercles, dorsomesial margin not delimited, rounded surface with abundance of long setae and small tubercles, two more prominent, teardrop-shaped small spines proximally; rounded ventromesial surface with low tubercles or granules becoming obsolete toward cutting edge. Palm approximately 1.3 length of carpus; dorsomesial margin with row of prominent spines, accompanied by long, simple setae, flat dorsal surface with covering of moderately long and stiff, simple setae, dorsolateral margin not delimited; rounded dorsolateral surface with short setae, closely-spaced spinulose tubercles and tuberculate spines extending almost full length of fixed finger; rounded mesial and lateral surfaces with closely-spaced tubercles becoming obsolete on ventral surface; cutting edge of fixed finger with one prominent tooth and row of fused calcareous teeth, terminating in small corneous claw. Carpus approximately half length of merus, broadly subtriangular in dorsal view; dorsodistal margin unarmed but with row of moderately long setae, dorsomesial margin with prominent, acute spines and few long setae, dorsal surface with scattered short setae and stiff bristles, dorsolateral margin not delimited; ventrolateral margin with row of small spines; lateral, mesial and ventral surfaces unarmed. Merus roundly subtriangular; dorsodistal margin with small spine, dorsal margin with few tufts of fine setae; ventromesial and ventrolateral margins each with row of small, acute spines; ventral surface with few minute granules. Ischium with row of very small spines on ventromesial margin, ventral surface with few minute spinules. Coxa with one large and two smaller spines on ventrodistal margin and two small spines on ventromesial margin. Left cheliped ( Fig. 2D ) short, slender. Dactyl approximately 0.8 as long as palm. Dactyl, palm and fixed finger all unarmed, but with irregular rows of stiff bristles. Carpus with row of very stiff bristles on both dorsomesial and dorsolateral margins, dorsolateral margin also with one spine proximally and spinule at distal margin, dorsomesial margin with two small spines proximally. Merus with small spine at dorsodistal margin, dorsal surface with sparse tufts of fine setae; laterodistal margin with small spine ventrally; ventromesial margin with two spines in proximal half. Ischium with three widely-spaced spines on ventromesial margin. Coxa with one spine on ventrodistal margin.

Second and third pereopods ( Fig. 2E, F ) generally similar (right second missing). Dactyls 1.3-1.4 length of propodi; dorsal surfaces each with row of tufts of moderately long, stiff setae; mesial faces each with numerous but randomly set, moderately short, stiff bristles; ventral margins each with row of six or seven corneous spines and few setae. Propodi each with tufts of moderately long setae dorsally; mesial faces with randomly scattered, moderately short, stiff bristles; ventrodistal margins each with one or two corneous spinules and one or two additional corneous spinules in distal half. Carpi each with spine at dorsodistal angle, dorsal surface with or without one smaller spine at midlength and one to three small spines in proximal half. Meri with scattered setae on dorsal and ventral margins. Ischia unarmed. Coxae each with four or five prominent spines on ventromesial margin (second) or unarmed (third). Fourth pereopods with propodal rasp consisting of three or four rows of sharp corneous scales; dactyl with small terminal claw. Anterior lobe of sternite of third pereopods subtriangular. Pleon moderately short. Distal segments of twosegmented male paired second pleopods ( Fig. 2G ) each with terminal tuft of long setae. Tergite of sixth pleomere divided unequally by incomplete, transverse suture; both portions well calcified with moderately dense covering of short setae. Uropods symmetrical. Telson ( Fig. 2H ) longer than broad, subtrapezoidal, unarmed, terminal margin with row of setae.

AFFINITIES

In the shape of the shield and cephalic appendages L. boucheti n. sp. more closely resembles L. yucatanicus than L. tribulomanus n. sp. However, in place of the short rostral keel of L. yucatanicus , L. boucheti n. sp. has a very distinctive rostral spine that actually arises from the dorsal surface of the shield rather than from the anterior margin. The anterolateral margins of the shield are also distinctive in the new species in that they each carry a prominent, posterolaterally directed spine. The general shapes of the right and left chelipeds are similar in L. yucatanicus and L. boucheti n. sp., although the armature appears to be variable in L. yucatanicus . For example, Provenzano (1968) described the carpus of the right cheliped as having spines on both the [dorso]lateral and [dorso]medial (mesial) margins; however, no dorsolateral spines were illustrated for the female paratype ( Provenzano 1968: fig. 3, left and center), nor did we find such spines in the MNHN paratype. Similarly, and as previously mentioned, Provenzano described the left cheliped of the western Atlantic species as having two or three large spines on the dorsal surface of the carpus, whereas one spine, in addition to the dorsodistal spine, was illustrated for the female paratype (1968: fig. 2, upper left). We found no spines on the carpus of that paratype.

Figures

FIG. 2. — Lithopagurus boucheti n. sp., holotype (MNHN-Pg 7079), Fiji, BORDAU 1, stn DW 1486, 19°01’S, 178°26’W, 385-540 m, 10.III.1999; A, right side of shield, dorsolateral view; B, shield and cephalic appendages (aesthetascs omitted); C, chela and carpus of right cheliped, dorsal view; D, chela and carpus of left cheliped, dorsal view; E, left second pereopod, lateral view; F, left third pereopod, lateral view; G, right second pleopod; H, telson. Scale bar: A-F, 1.0 mm; G, H, 0.5 mm.