Pylopaguropsis bellula Osawa & Okuno, 2007

(Fig. 3A)

Pylopaguropsis bellula Osawa & Okuno, 2007: 31, figs. 1–5, 6A, B, 7A, B (type locality: Kume Island, Ryukyu Islands).

Material examined. Ie Island, unnamed submarine cave: main tube, 7 September 2016, 2 males (sl 2.9, 3.3 mm), 1 ovigerous female (sl 4.6 mm), RUMF-ZC-6041 (IE 13); main tube, near bifurcation of tube, 7 September 2016, 1 male (sl 4.1 mm), RUMF-ZC-6042 (IE 17); main tube, near bifurcation of tube, 8 September 2016, 1 male (sl 3.6 mm), RUMF-ZC-6043 (IE 59). Okinawa Island, Hedo Dome cave: main tube, 11 August 2016, 1 male (sl 2.6 mm), RUMF-ZC-6044 (HD 2016-67). Shimoji Island, Akuma-no-Yakata cave: entrance, 1 September 2017, 1 male (sl 3.8 mm), RUMF-ZC-6045 (SH 101).

Distribution. Ryukyu Islands (Ie Island, Okinawa Island, Kume Island, and Shimoji Island) in southwestern Japan; 15–35 m (Osawa & Okuno 2007; present study).

Habitat. Coral reefs; found in submarine caves and crevices of fore-reef slopes (Osawa & Okuno 2007).

Remarks. Five species of the genus Pylopaguropsis Alcock, 1905, P. bellula, P. fimbriata, P. granulata, P. keijii, and P. speciosa, have been recorded from the submarine caves in the Ryukyu Islands (Osawa & Takeda 2004; Osawa & Okuno 2007; Osawa & Fujita 2016; present study; Table 2). The dactyli and propodi of the ambulatory legs are solid-colored in P. bellula and P. keijii, whereas those of P. fimbriata, P. granulata, and P. speciosa have white stripes (Fig. 3). Although such a solid coloration of the ambulatory legs is also known in another congener P. furusei Asakura, 2000, it is uncommon and usually striped in other Pylopaguropsis species.