Pilumnus tahitensis De Man, 1890

deVries, Maaike, McGillis Hall, Linda, Dainty, Katie, Fan, Mark, Tscheng, Dorothy, Hamilton, Michael & Trbovich, Patricia, 2024, Ten Species of Crabs of the Families Acidopsidae, Aphanodactylidae and Pilumnidae (Crustacea: Decapoda: Brachyura) from the Ogasawara Islands, Japan, Bulletin of the National Museum of Nature and Science. Series A, Zoology 50 (4), pp. 155-169 : 164

Pilumnus tahitensis De Man, 1890 [NJn: Tahichi-kebukagani]

( Fig. 4A–C )

Pilumnus tahitensis De Man, 1890, p 61 , pl. 3 fig. 4. — Ortmann, 1893, p. 437. — Rathbun, 1907, p. 56; 1911, p. 229. — Balss, 1933, p. 25; 1938, p. 68. — Miyake, 1939, p. 218 (in list). — Holthuis, 1953, p. 25. — Forest & Guinot, 1961, p. 129, fig. 125. — Takeda & Miyake, 1968, pp. 6 (in key), 15.

Material examined. ɹ Chichi-jima Is. —Sujiiwa-misaki (27°07′50′′N, 142°10′46′′E), Ani-jima I., 9 m, 1 ˁ (cb 6.2×cl 4.9 mm), NSMT-Cr 32402, 27-VI-2014, coll. by H. Komatsu.

Remarks. ɹ As stressed by the original author (De Man, 1890) and Takeda and Miyake (1968), the upper margin of the movable finger and the lower margin of the immovable finger, and the outer surface of each finger are thickly crested throughout the whole lengths, leaving a longitudinal deep furrow between the crests in each finger ( Fig. 4C ). The long club-shaped hairs covering the carapace, chelipeds and ambulatory legs and the narrow carapace armed with three sharp anterolateral spines are as seen in Fig. 4A–B . The outer halves of the supraorbital and infraorbital margins are raised and thin to form the deep orbit, with a deep cleft just below the external orbital part, with a spinule as the external orbital angle. A subhepatic spinule is seen between the external orbital angle and the first anterolateral spine.

Distribution. ɹ Although the records of occurrence are not many, but the geographical range is wide from Madagascar and Seychelles in the western Indian Ocean to Tahiti and Tuamotu Islands in the southern Pacific Ocean and to the Solomon Islands and Micronesian islands in the western Pacific Ocean. New to Japanese waters.

Figures

Fig. 4. A–C: Pilumnus tahitensis De Man, ˁ (NSMT-Cr 32402; cb 6.2×cl 4.9 mm) from Sujiiwa-misaki, Anijima I. D–E: Nanopilumnus heterodon (Sakai), ˁ (NSMT-Cr 32394; cb 7.9×cl 5.7mm) from Omura Beach, Chichi-jima I. F: Crinitocinus alcocki (Borradaile), juv. (NSMT-Cr 323889; cb 4.7×cl 3.8mm) found in stomach contents of sidespot goatfish, Parupeneus pleurostigma (Bennett) from off Futami Bay, Chichi-jima I.