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

description: Micropagurus propinquus n. sp. (Figs. 3–6, 20)   
 Type material. Holotype: ♂, SL = 1.6 mm, 10 m, Miyano­hama, Chichijima Island, Ogasawara Islands, coll. Hiroyuki Tachikawa, 4 Feb. 1995, CBM­ZC 8378. Paratype: 1♂, SL = 1.5 mm, 3 m, Miyano­hama, Chichijima Island, Ogasawara Islands, coll. Hiroyuki Tachikawa, 16 Apr. 1995, CBM­ZC 8379.   
 Description. Shield (Fig. 3A) approximately as long as broad; anterior margin between rostral lobe and lateral projections weakly concave; posterior margin truncate; dorsal surface with rows or tufts of setae. Rostral lobe (Fig. 3B) slightly produced, broadly rounded. Lateral projections (Fig. 3B) broadly rounded, unarmed.   
Ocular peduncles (Fig. 3A) approximately as long as shield, slightly inflated basally; corneas dilated. Paired interocular lobes (Fig. 3B) prominent. Ocular acicles (Fig. 3B) each with 4 or 5 spines on distal margin and with fringe of setae just proximal to spine row.  
Antennular peduncles (Fig. 3A) reaching to bases of corneas; all segments unarmed.  
Antennal peduncles (Fig. 3A, D–F) reaching to bases of corneas; fifth segment unarmed; fourth segment with sharp spine at dorsodistal angle; 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. Antennal acicle (Fig. 3D–F) moderately short, terminating in small spine; lateral margin with subproximal spine. Flagella sparsely setose (Fig. 3G).  
Third maxilliped (Fig. 3H, I) with basis bearing sharp tooth; ischium with moderatelydeveloped crista dentata and accessory tooth; merus and carpus each with strong dorsodistal spine.  
Right cheliped (Fig. 4) stout. Dactyl 0.6–0.7 length of palm; cutting edge (Fig. 4D) with single calcareous tooth proximally and row of tiny corneous or calcareous teeth distally; dorsomesial margin with 4 sharp spines. Palm 1.0–1.1 length of carpus; dorsal surface flat, with longitudinal row of 4 strong spines or tubercles slightly mesiad of midline in proximal half and longitudinal row of 3 strong spines or tubercles along midline in distal half, not extending onto fixed finger; dorsomesial margin with row of 6 or 7 strong spines; dorsolateral margin with row of strong spines extending onto fixed finger; cutting edge of fixed finger (Fig. 4D) with few variously­sized calcareous teeth proximally and row of tiny calcareous and corneous teeth distally. Carpus 1.0–1.1 length of merus; dorsomesial margin with row of 4–6 strong spines; dorsolateral margin with row of 4 strong spines. Merus with ventromesial margin bearing single strong spine or unarmed; ventrolateral margin with 2 strong, sharp spines or unarmed. Ischium with row of large tubercles on ventromesial margin and sharp distal spine on ventromesial margin, or unarmed.  
Left cheliped (Fig. 5) slender. Dactyl 0.9–1.0 length of palm, terminating in sharp corneous claw; dorsomesial margin with 1 or 2 small spines; cutting edge (Fig. 5D) with row of small, sharp corneous teeth. Palm 0.6–0.7 length of carpus; dorsal surface with longitudinal row of 4 strong spines and additional 2 strong spines mesially; dorsolateral margin with row of 6–8 strong spines extending onto fixed finger; fixed finger terminating in sharp corneous claw, cutting edge (Fig. 5D) with row of calcareous teeth in distal half. Carpus 0.9–1.0 length of merus; dorsomesial margin with row of 4 very strong spines, dorsolateral margin with row of 3 very strong spines. Merus with ventromesial margin bearing 2 strong spines; ventrolateral margin with 1 very strong spine medially and small subdistal spine. Ischium with ventromesial margin bearing row of 4 spines; ventrolateral face with sharp spine.  
Second (Fig. 6A, B) and third (Fig. 6C, D) pereopods generally similar; second slightly shorter and carpal armature stronger than third. Dactyls 0.9–1.0 (second) or 1.1– 1.2 (third) length of propodi, each terminating in strong corneous claw; slightly curved ventrally in lateral view; ventral margins each with 4–6 (left) or 4–5 (right) corneous spines (second), or 5–7 (left) or 6–7 (right) corneous spines (third). Propodi 1.6–1.7 (second) or 1.7–1.8 (third) length of carpi; ventrodistal margins each with sharp corneous spine or unarmed. Carpi 0.6–0.7 length of meri; dorsal surfaces each with generally 3 (rarely 4) strong spines. Meri and ischia unarmed.  
Sternite of third pereopods with broad, subrectangular anterior lobe (Fig. 6F) bearing setae anteriorly.  
Fourth pereopod (Fig. 6E) with propodal rasp composed of 2 or 3 rows of corneous scales.  
Male with coxa of left fifth pereopod (Fig. 6G) bearing well­developed sexual tube; no gonopore on right coxa. Female unknown.  
Pleon with well­developed columellar muscle near anterior margin ventrally (Fig. 6G).  
Telson (Fig. 6H) rounded, unarmed.  
 Coloration. Unknown.   
 Etymology. The specific epithet is from the Latin propinquus, meaning related or similar, and reflects morphological similarity of this species to M. devaneyi.   
 Remarks: This species is most similar to M. devaneyi but is easily distinguished from the latter in having a greater number of corneous spines on the ventral margins of the ambulatory dactyls; in M. propinquus, the second pereopods have 4–6 spines (Fig. 6A, B), and the thirds have 5–7 spines (Fig. 6C, D). However, both the second and third pereopods of M. devaneyi have only 2–4 (generally 2 or 3) spines. Additionally, the ventrolateral margin of the merus of the left cheliped is unarmed in M. devaneyi. However, the same margin of M. propinquus is armed with 1 strong spine in proximal half and 1 smaller spine near distal margin (Fig. 5C). Generally, spines on the chelipeds and the carpi of the ambulatory pereopods of M. propinquus are much stronger than those of M. devaneyi.   
 Distribution. Known only from the type locality, Chichijima Island, Ogasawara Islands; 3– 10 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 6-11, DOI: 10.11646/zootaxa.1090.1.1, http://zenodo.org/record/5050939