Micropagurus spinimanus, Asakura, 2005

Asakura, Akira, 2005, A review of the genus Micropagurus (Crustacea Decapoda Anomura Paguridae), Zootaxa 1090 (1), pp. 1-34 : 13-21

publication ID	https://doi.org/ 10.11646/zootaxa.1090.1.1
publication LSID	lsid:zoobank.org:pub:172D3D3A-0929-48AB-9BDE-A81674FD854C
DOI	https://doi.org/10.5281/zenodo.10533220
persistent identifier	https://treatment.plazi.org/id/03C687CF-2E4B-FFEC-FECA-FED8FC13BD68
treatment provided by	Felipe
scientific name	Micropagurus spinimanus
status	sp. nov.

Treatment

Micropagurus spinimanus View in CoL n. sp. ( Figs. 7–13 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 , 20 View FIGURE 20 )

Type material. Holotype, ♂, SL = 2.6 mm, sand flat on the reef, islet, Touho, New Caledonia, 6 Sept. 1993, MNHNPg 7265. Paratypes: PACIFIC OCEAN: Loyalty Islands: 1♂, SL = 2.0 mm, stn. 1422, 4 m, sand with fragments and rubbles, small inlet, east of Pte d'Easo, Santal Bay, Lifou Island, 20°47.1'S, 167°07.4' E, 13, 17, 25 Nov. 2000, LIFOU, MNHNPg 7266; 1♀, SL = 1.9 mm, stn. 1430, 20 25 m, coral boulders, west or southwest of Pte d'Easo, Santal Bay, Lifou Island, 20°47.5'S, 167°07.1' E, 9 Nov. 2000, LIFOU, MNHNPg 7267; 1♀, SL = 2.0 mm, stn. 1419, 5 m, mud with fragments and algae, Gaatcha Bay, Santal Bay, Lifou Island, 20°55.6'S, 167°04.5' E, 10 Nov. 2000, LIFOU, MNHNPg 7268; 1♂, SL = 2.6 mm, stn. 1446, 36 40 m, underwater cliff, Mepinyo, east of the Santa Bay, Lifou Island, 20°50.8'S, 167°09.7' E, 16 Nov. 2000, LIFOU, MNHNPg 7269; 1 ov. ♀, SL = 2.4 mm, stn. 1421, 4 m, coarse sand with fragments, between Huca Hutighé Islet and the bay coast, Santal Bay, Lifou Island, 20°52.4'S, 167°08.5' E, 26, 27 Nov. 2000, LIFOU, MNHNPg 7270; New Caledonia: 1♂, SL = 1.4 mm, 1 m, on red algae, lagoon, 20°42.15'S, 167°09.90'E, 28 Dec. 1995, MNHNPg 7272; 1♂, SL = 1.3 mm, sand, islet, Touho, 7 Sept. 1993, MNHNPg 7273; 1♀, SL = 1.5 mm, 2030 m, lagoon, Grotte Merlet, coll. J.L. Menou, 1921 Jan. 1993, MNHNPg 7274; Chesterfield Islands: 1♂, SL = 2.9 mm, st. DW 38, 61 m, 19°21.62'S, 158°42.50', coll. Richer de Forges ( ORSTOM), 23 July 1988, CORAIL 2, MNHNPg 7275; INDIAN OCEAN: Indonesia: 1♂, SL = 1.4 mm, Siboga st. 315, up to 36 m, coral and Lithothamnion , dredge, east of Sailus Besar, Paternoster Islands, Indonesia, 7°S, 117°E, 1718 Feb. 1900, MNHNPg 7277; Seychelles: 1♂, SL = 2.9 mm, st. 38, 44 m, hard bottom, on dead coral blocks, Mélobésiées, 5°03.5'S, 56°50.5'E, 13 Sept. 1980, Campagne REVES II, coll. R. Cleva, MNHNPg 7276; Madagascar: 1♀, SL = 2.9 mm, st. 59913, Tuléar (= Toliara), coll. B. Thomassuii, MNHNPg 3294 (det. M. polynesiensis by M. de St. Laurent).

Description. Shield approximately as long as broad ( Fig. 7A, B View FIGURE 7 ) or slightly broader than long ( Fig. 7C View FIGURE 7 ); anterior margin between rostral lobe and lateral projections weakly concave; posterior margin roundly truncate; dorsal surface with rows of tufts of moderately long setae. Rostral lobe slightly produced, broadly rounded. Lateral projections broadly rounded, unarmed.

Ocular peduncles ( Fig. 7A–C View FIGURE 7 ) approximately as long as shield; slightly inflated basally; corneas slightly dilated. Paired interocular lobes prominent. Ocular acicles each with 4 or 5 spines on distal margin and with fringe of setae just proximal to spine row.

Antennular peduncles ( Fig. 7A–C View FIGURE 7 ) rarely reaching to bases of corneas; all segments unarmed.

Antennal peduncles ( Fig. 7A–E View FIGURE 7 ) reaching to only 0.7 lengths of ocular peduncles; fifth and fourth segments unarmed; third segment with sharp spine at ventrodistal margin; second segment with dorsolateral distal angle produced and terminating in simple or bifid spine; dorsomesial distal angle with small spine; first segment with sharp spine on lateral margin distally and additional spine at ventrodistal margin. Antennal acicle moderately short, terminating in small spine; lateral margin with or without spine proximally.

Third maxilliped ( Fig. 7E, F View FIGURE 7 ) with basis bearing 1 or 2 sharp teeth; ischium with moderately developed crista dentata and accessory tooth; merus and carpus each with strong dorsodistal spine.

Right cheliped ( Figs. 8 View FIGURE 8 , 9 View FIGURE 9 ) stout; in large individuals, female chela ( Fig. 9 View FIGURE 9 ) slightly broader than male ( Fig. 8 View FIGURE 8 ); spines on dorsal, dorsomesial and dorsolateral faces of dactyl and palm generally simple ( Fig. 8B View FIGURE 8 ) but rarely bifid ( Fig. 9B View FIGURE 9 ). Dactyl 0.5–0.6 (male) or 0.6–0.7 (female) length of palm; cutting edge ( Figs. 8D View FIGURE 8 , 9D, E View FIGURE 9 ) with 2 or 3 large calcareous teeth proximally and row of tiny corneous and calcareous teeth distally; dorsomesial margin with 4–6 large spines and occasionally with additional 1–3 spines on dorsal face mesially. Palm 1.1–1.2 (male) or 1.0–1.1 (female) length of carpus; dorsal surface flat, armature variable ( Figs. 8B View FIGURE 8 , 9B View FIGURE 9 , 10A–D View FIGURE 10 ), viz., with irregular 2–4 longitudinal rows of strong spines, occasionally extending onto proximal portion of fixed finger; dorsomesial margin with row of 5–7 strong spines; dorsolateral margin with row of strong spines extending onto fixed finger; cutting edge of fixed finger ( Figs. 8D View FIGURE 8 , 9D, E View FIGURE 9 ) with several variouslysized calcareous teeth proximally and row of tiny calcareous and corneous teeth distally. Carpus 0.9–1.0 (male) or 0.8–0.9 (female) length of merus; dorsomesial margin with row of 4–7 strong spines; dorsolateral margin with row of 4–6 strong spines. Merus with 1 or 2 strong spines on ventromesial margin or unarmed. Ischium with strong spine on ventrolateral margin.

Left cheliped ( Fig. 11 View FIGURE 11 ) slender. Dactyl 0.8–0.9 length of palm, terminating in sharp corneous claw; cutting edge ( Fig. 11D View FIGURE 11 ) with row of small, sharp corneous teeth. Palm 0.7– 0.8 length of carpus; dorsal surface with longitudinal row of 4–6 spines; dorsolateral margin with row of small spines extending onto fixed finger; dorsomesial margin unarmed or with 1 or 2 small spines; fixed finger terminating in sharp corneous claw, cutting edge ( Fig. 11D View FIGURE 11 ) with row of corneous teeth. Carpus 0.7–0.8 length of merus; dorsomesial and dorsolateral margins each with row of spines. Merus with ventromesial margin bearing 1 or 2 spines, or unarmed; ventrolateral margin with 2–4 small spines. Ischium with ventromesial margin bearing row of low protuberances and with or without sharp spine; ventrolateral margin with sharp spine.

Second ( Fig. 12A–D View FIGURE 12 ) and third ( Fig. 12E–I View FIGURE 12 ) pereopods generally similar; second shorter and carpi armature much stronger than third. Dactyls 0.9–1.0 (second) or 1.1–1.2 (third) length of propodi, each terminating in strong corneous claw; ventral margins each with 3–5 (second) or 3–7 (third) corneous spines; mesial margins each with dorsal row of spinelike thick setae. Propodi 1.7–1.8 (second) or 1.6–1.7 (third) length of carpi; ventrodistal margins each with sharp corneous spine. Carpi 0.5–0.6 (second) or 0.7–0.8 (third) length of meri; dorsal surfaces each with generally 3 (2–4) spines. Meri and ischia unarmed.

Sternite of third pereopods with broad, subrectangular anterior lobe ( Fig. 13B View FIGURE 13 ) bearing setae anteriorly.

Fourth pereopod ( Fig. 13A View FIGURE 13 ) with propodal rasp composed of 2 or 3 rows of scales.

Male with coxa of left fifth pereopod ( Fig. 13C, D View FIGURE 13 ) bearing welldeveloped sexual tube; right coxa with gonopore ( Fig. 13C View FIGURE 13 ) and sometimes with very short extrusion of vas deferens ( Fig. 13D View FIGURE 13 ), or without gonopore (see remarks).

Pleon with welldeveloped columellar muscle near anterior margin ventrally ( Fig. 13C, D View FIGURE 13 ).

Telson ( Fig. 13E–G View FIGURE 13 ) with terminal margin rounded, unarmed or with 1 or 2 minute spinules on each side laterally.

Coloration. Live coloration unknown. In preservative, dorsal longitudinal dark stripe present on each antennular peduncle and fifth segment of antennal peduncle ( Fig. 7B View FIGURE 7 ).

Etymology. From the Latin spina, meaning spine, and manus, meaning palm, referring to the spinulose palm of the right cheliped in this species.

Remarks. Large females of this species have the right cheliped broader than males. This contrasts with the condition in M. polynesiensis , where the female right cheliped is more slender than in the male.

In this species, development of the male right gonopore seems variable; the right gonopore is not open (e.g., MNHNPg 7273); the gonopore is not open but a hollow is seen on the right coxa (e.g., MNHNPg 7266); the right gonopore is apparently open ( Fig. 13C View FIGURE 13 , MNHNPg 7265); a very short protrusion of a sexual tube is seen on the right coxa ( Fig. 13D View FIGURE 13 , MNHNPg 7276). However, this condition is most probably due to growth related differences, as smaller males have smaller right gonopores or no gonopores.

The combination of characters, including the multiple rows of strong spines on the palm of the right chela ( Figs. 8B View FIGURE 8 , 9B View FIGURE 9 , 10 View FIGURE 10 ) and the dorsal row of spinelike thick setae on each mesial face of the ambulatory dactyls ( Fig. 12B, D, F, H View FIGURE 12 ), sets this species apart from all other species of Micropagurus . If the color pattern is preserved on the specimens, this species is distinguished by having a dorsal longitudinal dark stripe on each antennular peduncle and fifth segment of the antennal peduncle ( Fig. 7B View FIGURE 7 ).