Micropagurus propinquus, Asakura, 2005

Asakura, Akira, 2005, A review of the genus Micropagurus (Crustacea Decapoda Anomura Paguridae), Zootaxa 1090 (1), pp. 1-34 : 6-11

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.10533218
persistent identifier	https://treatment.plazi.org/id/03C687CF-2E42-FFF2-FECA-FE1AFE43BCD8
treatment provided by	Felipe
scientific name	Micropagurus propinquus
status	sp. nov.

Treatment

Micropagurus propinquus View in CoL n. sp. ( Figs. 3–6 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 , 20 View FIGURE 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 View FIGURE 3 ) 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 View FIGURE 3 ) slightly produced, broadly rounded. Lateral projections ( Fig. 3B View FIGURE 3 ) broadly rounded, unarmed.

Ocular peduncles ( Fig. 3A View FIGURE 3 ) approximately as long as shield, slightly inflated basally; corneas dilated. Paired interocular lobes ( Fig. 3B View FIGURE 3 ) prominent. Ocular acicles ( Fig. 3B View FIGURE 3 ) each with 4 or 5 spines on distal margin and with fringe of setae just proximal to spine row.

Antennular peduncles ( Fig. 3A View FIGURE 3 ) reaching to bases of corneas; all segments unarmed.

Antennal peduncles ( Fig. 3A, D–F View FIGURE 3 ) 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 View FIGURE 3 ) moderately short, terminating in small spine; lateral margin with subproximal spine. Flagella sparsely setose ( Fig. 3G View FIGURE 3 ).

Third maxilliped ( Fig. 3H, I View FIGURE 3 ) 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 View FIGURE 4 ) stout. Dactyl 0.6–0.7 length of palm; cutting edge ( Fig. 4D View FIGURE 4 ) 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 View FIGURE 4 ) 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 View FIGURE 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 View FIGURE 5 ) 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 View FIGURE 5 ) 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 View FIGURE 6 ) and third ( Fig. 6C, D View FIGURE 6 ) 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 View FIGURE 6 ) bearing setae anteriorly.

Fourth pereopod ( Fig. 6E View FIGURE 6 ) with propodal rasp composed of 2 or 3 rows of corneous scales.

Male with coxa of left fifth pereopod ( Fig. 6G View FIGURE 6 ) bearing welldeveloped sexual tube; no gonopore on right coxa. Female unknown.

Pleon with welldeveloped columellar muscle near anterior margin ventrally ( Fig. 6G View FIGURE 6 ).

Telson ( Fig. 6H View FIGURE 6 ) 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 View FIGURE 6 ), and the thirds have 5–7 spines ( Fig. 6C, D View FIGURE 6 ). 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 View FIGURE 5 ). Generally, spines on the chelipeds and the carpi of the ambulatory pereopods of M. propinquus are much stronger than those of M. devaneyi .