Paguropsis lacinia, Lemaitre, Rafael, Rahayu, Dwi Listyo & Komai, Tomoyuki, 2018

Lemaitre, Rafael, Rahayu, Dwi Listyo & Komai, Tomoyuki, 2018, A revision of " blanket-hermit crabs " of the genus Paguropsis Henderson, 1888, with the description of a new genus and five new species (Crustacea, Anomura, Diogenidae), ZooKeys 752, pp. 17-97 : 59-64

Paguropsis lacinia sp. n. Figs 18B, 19, 20, 21 A–C, 22, Table 1

Type material.

Holotype: female 8.4 mm, Solomon Islands, SALOMON 2, NOAlis, NW of Isabel Island, staCP 2201, 07°43.5'S, 158°29.9'E, 307-310 m, 25 Oct 2004 (USNM 1442006).

Paratypes.

Papua New Guinea: MADEEP, NOAlis: NW of Kavieng, staCP 4254, 02°28'S, 150°42'E, 273-324 m, 24 Apr 2014: 1 female 9.8 mm, color photograph (Fig. 18B) (MNHN-IU-2013-2288).

Salomon Islands: SALOMON 1, NOAlis: N Buena Vista Island, staDW 1765, 08°43'S, 160°07'E, 325-380 m, 27 Sep 2001: 1 female 6.1 mm (MNHN-IU-2014-9370); NW of San Cristobal, staCP 1831, 10°12'S, 161°19'E, 135-325 m, 5 Oct 2001: 1 ovig female 10.3 mm (MNHN-IU-2014-9367).

Tonga Islands: BORDAU 2, NOAlis: NW of Tongatapu, staCP 1643, 21°05'S, 175°22'W, 487 m, 22 Jun 2000: 1 male 7.3 mm, 1 female 7.2 mm (MNHN-IU-2014-9366).

New Caledonia: NORFOLK 1, NOAlis: Norfolk Ridge, Crypthelia Bank, staCP 1731, 23°21'S, 168°16'E, 310-788 m, 27 Jun 2001: 1 male 8.5 mm (MNHN-IU-2014-9360). NORFOLK 2, NOAlis: Munida Bank, staDW 2142, 23°01'S, 168°17'E, 550 m, 3 Nov 2003: 2 males 6.7, 6.8 mm (MNHN-IU-2014-9389). EBISCO, NOAlis: W of Bellona, staCP 2551, 21°06'S, 158°35'E, 637-650 m, 11 Oct 2005: 1 male 7.8 mm (USNM 1442007).

Description.

Shield (Figs 18B, 19A) weakly subtriangular (lateral margins subparallel on anterior two-thirds), 1.2 times as long as broad; dorsal surface glabrous except for tufts of setae anterolaterally and transverse fringe of short setae on sloping anterior margins of gastric region; anterior margin between rostrum and lateral projections concave; lateral projections broadly triangular, each terminating in small spine; pos terior margin relatively wide, roundly truncate; lateroventral distal angle with strong spine adjacent to proximal margin of first antennal segment. Rostrum acutely triangular, arched, and curving ventrally, extending nearly to distal margin of ocular acicles, terminating in small spine; with distinct rounded dorsal longitudinal ridge with fringe of short setae laterally, and terminating subdistally in rounded tip. Branchiostegite (Fig. 20A) unarmed except for 1 or 2 minute tubercles on dorsodistal angle of anterodorsal plate, and setose distal margin.

Ocular peduncles stout, constricted medially and broadening distally, ca. 0.5 length of shield, glabrous except for row of few short dorsodistal setae; corneas strongly dilated, diameter 0.5-0.6 total peduncular length (including the cornea). Ocular acicles small, triangular, armed with distal or dorsodistal spine often directed anteriorly or anterodorsally.

Antennular peduncles when fully extended overreaching distal margins of corneas by nearly full length of ultimate peduncular segments. Ultimate and penultimate segments glabrous or at most with scattered short setae. Basal segment with ventromesial setae distally; lateral face with distal subrectangular lobe with or without small tubercles, small medial spine, and setose lobe proximally.

Antennal peduncles reaching or at most slightly exceeding distal margin of corneas. Fifth and fourth segments unarmed except for scattered short setae and laterodistal tuft of long setae. Third segment with strong spine at ventrodistal angle. Second segment with dorsolateral distal angle produced, terminating in small simple spine; mesial margin rounded, setose, and small spine on dorsomesial angle. First segment unarmed. Antennal acicle reaching to proximal margin of cornea, slender, terminating in sharp spine, with long setae distally, at most with 1 or 2 minute proximal tubercles on mesial margin. Antennal flagellum long, reaching to distal end of cheliped fingers, articles with 1 or 2 short setae (<1 article in length) and usually with 1 or 2 long setae every 12 articles or so.

Mouthparts not markedly different from those described for Paguropsis typica (see Fig. 4 A–F). Maxilliped 3 with exopod ca. 4.2 times as long as broad.

Chelipeds (Figs 18B, 19B, C) subequal, similar in armature and setation; dorsal surfaces of chelae and carpi moderately covered with short bristle-like setae not obscuring armature below, setation somewhat denser near base of fixed finger and distal portion of palm; ventral surfaces of chelae and carpi with scant setae or tufts of setae, and scattered small tubercles. Dactyl and fixed finger with narrow hiatus proximally when closed, forming spoon-like shape in ventral view when closed; each terminating in small curved corneous claw and subdistal blunt calcareous tooth ventral to claw, both claws and teeth interlocking when fingers closed; cutting edge of dactyl with terminal row of small, fused corneous teeth on distal one-third, and row of unequal calcareous teeth on proximal two-thirds; cutting edge of fixed finger with row of blunt calcareous teeth decreasing in size distally. Dactyl 1.4 times as long as palm; dorsal surface convex, armed with small spines or tubercles; dorsomesial margin rounded, armed with small spines or tubercles; ventral face with well-spaced tufts of long bristle-like setae, lacking spines. Fixed finger with dorsal, lateral and ventral surfaces similar to dactyl in armature. Palm slightly shorter than carpus, dorsal surface with scattered small tubercles medially, dorsolateral margin rounded, not delimited, with irregular rows of small spines or tubercles, dorsomesial margin with row of strong spines. Carpus ca. 0.6 times length of merus; dorsal and dorsolateral surfaces with well-spaced small spines or tubercles; dorsomesial margin with row of strong spines or tubercles, and small dorsodistal spine; dorsolateral margin rounded, not delimited; mesial surface smooth, unarmed except for setae on distal margin; ventral surface unarmed, ventrodistal margin with fringe of sparse long setae. Merus nearly as long as chela, subtriangular in cross-section; dorsal margin with row of protuberances accompanied by tufts of short setae, ventromesial and ventrolateral margins each with irregular row of spines with setae; lateral and mesial surfaces unarmed except for scattered short setae. Ischium with row of small spines on ventrolateral margin. Basis with ventromesial row of setae. Coxa with well-marked longitudinal fissure (Fig. 21A) on ventral surface.

Pereopods 2 and 3 (Figs 18B, 22 A–D) similar in armature and setation, distinctly dissimilar in length, with pereopod 2 shorter than 3. Dactyls ca. 1.7 (pereopod 2) or 2.4 (pereopod 3) times as long as propodi; dactyl of pereopod 2 broadly curved, terminating in sharp corneous claw, with ventromesial distal row of usually ten minute short spinules; dactyl of pereopod 3 slender, nearly straight in lateral view, 1.5-1.6 times as long as dactyl of pereopod 2, ventromesial margin unarmed; dorsal and ventral margins with tufts of moderately long setae. Propodi 1.3-1.4 times as long as carpi; dorsal and ventral surfaces with tufts of long setae. Carpi unarmed except for tufts of setae dorsally, dorsodistal angle blunt or with obscure small tubercle. Meri unarmed except for fringe of long setae ventrally. Ischia unarmed except for scattered short setae. Coxae with ventromesial row of setae. Coxae of pereopods 3 (Figs 20B, 21A) separated by ca. 0.3 ventral length of 1 coxa. Anterior lobe of sternite XI (between pereopods 3; Fig. 21A) flat or slightly concave, unarmed, posterior lobes weakly arched, sloping, each with transverse fringe of sparse setae.

Pereopod 4 with chela (Fig. 21B) ca. 1.2 times as long as carpus and 1.7 times as long as high, palm 1.8-1.9 as long as high. Dactyl and fixed finger leaving wide gap when closed, each terminating in sharp, inwardly curved corneous claw crossing at tips when closed. Dactyl strongly curved inward, dorsal margin sparsely setose; cutting edge with ventrolateral row of usually 3 small corneous-tipped spines (in addition to corneous claw). Fixed finger curving inward, cutting edge with 4 strong corneous-tipped spines (in addition to corneous claw) arranged like bear claw; lateral face usually with 1 or 2 minute scale-like corneous spines near base of finger. Palm straight or slightly curved, dorsal face with prominent patch (Fig. 21B, C) of dense long, narrow capsulate setae extending for one-third of lateral surface. Carpus unarmed except for fringe of long setae dorsally and scattered setae ventrally. Merus ca. 0.7 times as long as meri of pereopods 2 and 3. Sternite XII (Fig. 20B) narrow, undivided or obscurely divided medially, with transverse fringe of long setae.

Pereopod 5 (Fig. 22G) with chela as long or slightly longer than carpus, and 0.7 times as long as merus. Chela with long, brush-like setae on dorsomesial and ventromesial face, Carpus with sparse tufts of setae on dorsal and ventral margins. Dactyl with rasp on ventral face. Propodal rasp weakly developed and consisting of minute, ovate scales, occupying 0.3 length of propodus. Ischium with setae dorsally and ventrally. Coxa with ventrodistal setae.

Male gonopod 1 with inferior lamella armed on distal margin with posterior row of slender, semitransparent hook-like spines, and 1 or 2 irregular rows of small straight or slightly curved corneous spines. Gonopod 2 with distal segment strongly twisted distally, densely setose. Pleon with left unpaired, reduced, biramous pleopods 3 and 4, lacking pleopod 5.

Female with left side having unpaired pleopods 2-4, and reduced biramous pleopod 5 (no unpaired pleopods 2-5 on right side). Brood pouch large, subquadrate, distal margin scalloped and fringed with setae.

Uropodal exopods (Fig. 19D) slender, nearly straight or broadly rounded, terminating in strong spine, anterior margin with fringe of long well-spaced setae and row of well-spaced corneous-tipped spines; endopods short, strongly curved, anterior margin with long setae and 1 or 2 irregular rows of corneous-tipped spines; protopods with strong, curved proximal spine.

Telson (Fig. 19D) subquadrate; posterior lobes separated by obsolete median cleft, terminal margins unarmed except for fringe of long setae.

Genetic data.

See Table 1.

Color

(Fig. 18B). Shield and calcified portion of posteromedian carapace evenly yellowish orange. Ocular peduncles yellowish orange except for white portions adjacent to corneas; corneas black; ocular acicles yellowish orange. Antennules and antennae light orange or pink, flagella of similar but darker color than peduncle but lighter. Chelipeds generally yellowish orange with white spines or tubercles; chelae proximally of lighter tone than rest of chelipeds, fading to nearly white or cream on dactyls and fixed fingers; carpi of darkest orange tone, ventromesial angle with reddish portion; meri light orange, with very short reddish stripe on distolateral and distomesial margin. Pereopods 2 and 3 with meri, carpi and propodi each with red spot distally on lateral face; dactyl light orange fading to white distally, and white dorsal margin; propodi and carpi light orange except for white distally around red spot; meri with light orange dorsal and ventral margins, otherwise white to cream except for red spot. Pereopod 4 more or less evenly orange except for white dactyl and fixed finger of chelae.

Etymology.

The species name is from the Latin lacinia, a fringe, and refers to the characteristic setae of this new species on the dorsal margin of the palm of the chelate pereopod 4.

Distribution.

Western Pacific: from off northern Papua New Guinea, Solomon Islands, Tonga Islands, and New Caledonia. Depth: 135 to 788 m.

Habitat and symbiont.

Found with indeterminate species of acontiate anemone (see “Remarks” under genus).

Variations.

No appreciable morphological variations were observed other than those incorporated in the description.

Affinities.

See “Affinities” under Paguropsis gigas sp. n.

Remarks.

The most prominent, distinctive morphological character of this species is the presence of a dense patch of capsulate, simple setae on the dorsal margin of the palms of pereopods 4 (Figs 21B, C, 22F), although a patch of capsulate setae is also present on the palm of pereopod 4 in Paguropsis gigas sp. n.. As noted under P. gigas sp. n., the extent and arrangement of the setae is different in these two species. The function, if any, of the patch is unknown. Furthermore, the unique coloration of P. lacinia sp. n., with pereopods 2 and 3 having meri, carpi and propodi each with a red spot distally on the lateral face (Fig. 18B), clearly distinguishes this species from other congeners.