Micropagurus spinimanus Asakura 2005, n. sp.
Creators: name: Asakura, Akira
Publisher: name: Zenodo
Year: 2005
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Paguridae
Micropagurus
Micropagurus spinimanus

description: Micropagurus spinimanus n. sp. (Figs. 7–13, 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) or slightly broader than long (Fig. 7C); 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) 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) rarely reaching to bases of corneas; all segments unarmed.  
Antennal peduncles (Fig. 7A–E) 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) 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, 9) stout; in large individuals, female chela (Fig. 9) slightly broader than male (Fig. 8); spines on dorsal, dorsomesial and dorsolateral faces of dactyl and palm generally simple (Fig. 8B) but rarely bifid (Fig. 9B). Dactyl 0.5–0.6 (male) or 0.6–0.7 (female) length of palm; cutting edge (Figs. 8D, 9D, E) 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, 9B, 10A–D), 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, 9D, E) 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) slender. Dactyl 0.8–0.9 length of palm, terminating in sharp corneous claw; cutting edge (Fig. 11D) 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) 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) and third (Fig. 12E–I) 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) bearing setae anteriorly.  
Fourth pereopod (Fig. 13A) with propodal rasp composed of 2 or 3 rows of scales.  
Male with coxa of left fifth pereopod (Fig. 13C, D) bearing well­developed sexual tube; right coxa with gonopore (Fig. 13C) and sometimes with very short extrusion of vas deferens (Fig. 13D), or without gonopore (see remarks).  
Pleon with well­developed columellar muscle near anterior margin ventrally (Fig. 13C, D).  
Telson (Fig. 13E–G) 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).   
 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, MNHN­Pg 7265); a very short protrusion of a sexual tube is seen on the right coxa (Fig. 13D, 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, 9B, 10) and the dorsal row of spine­like thick setae on each mesial face of the ambulatory dactyls (Fig. 12B, D, F, H), 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).   
 Distribution. West Pacific: Loyalty Islands, New Caledonia, Chesterfield Islands; 1– 61 m. Indian Ocean: Madagascar, Seychelles; 4– 44 m.
description: Published as part of Asakura, Akira, 2005, A review of the genus Micropagurus (Crustacea Decapoda Anomura Paguridae), pp. 1-34 in Zootaxa 1090 (1) on pages 13-21, DOI: 10.11646/zootaxa.1090.1.1, http://zenodo.org/record/5050939