Paguristes keijii, McLaughlin & Haig, 1989

Osawa, Masayuki & Fujita, Yoshihisa, 2019, Submarine cave hermit crabs (Crustacea: Decapoda: Anomura: Paguroidea) from three islands of the Ryukyu Islands, southwestern Japan, Zootaxa 4560 (3), pp. 463-482 : 475-476

Pylopaguropsis keijii McLaughlin & Haig, 1989

( Figs. 3D , 5F )

Pylopaguropsis keijii McLaughlin & Haig, 1989: 150 , figs. 2i, 3d, 5d, 7e, 9d, 11d, 13d (type locality: Oahu Island, Hawaiian Islands).— Asakura 2000: 82, figs. 6, 7, 19B, C, 20.

Material examined. Ie Island, unnamed submarine cave: entrance, 24 June 2017, 1 female (sl 2.1 mm), RUMF- ZC-6053 ( IE 172 ). Okinawa Island , Hedo Dome cave: main tube, 12 August 2016, 1 male (sl 2.8 mm) , 1 ovigerous female (sl 2.0 mm), RUMF-ZC-6054 ( HD 2016-81, 82); main tube, 21 May 2017, 1 male (sl 1.9 mm), RUMF-ZC-6055 ( HD 2017-87).

Distribution. Wide ranging in the Indo-West Pacific: Zanzibar, Mayotte, Maldives, Guam, Caroline Islands,

Japan (Ryukyu and Izu Islands), and Hawaii; 2.5–30 m ( McLaughlin & Haig 1989; Asakura 2000; Okuno & Arima 2006; Poupin et al. 2013).

Habitat. Coral reefs ( Asakura 2000; Poupin et al. 2013).

Remarks. Variations of coloration on the right cheliped are observed in the present material. The carpus and chela are purple in general and becomes paler or has white tint distally in three small specimens (male, sl 1.9 mm, RUMF-ZC-6055, HD 2017-87; female, sl 2.1 mm, RUMF-ZC-6053, IE172; ovigerous female, sl 2.0 mm, RUMF- ZC-6054, HD 2016-82), whereas they are whitish for most parts and have purple tint only on the mesial surfaces in the largest specimen (male, sl 2.8 mm, RUMF-ZC-6054, HD 2016-81). Poupin et al. (2013, fig. 26) also reported a male specimen (sl 3.0 mm), which agrees well with the present largest specimen in coloration of the right cheliped. Asakura (2000) cited that the right cheliped of P. keijii is generally fawn and gradually becomes white on the both fingers based on his larger material (sl 3.2, 3.4 mm). These suggest that the coloration of the right cheliped gradually changes from purple to fawn or white in accordance with the increase of specimen size.

Pylopaguropsis lemaitrei Asakura & Paulay, 2003 , described from French Polynesia, is a sibling species with overall coloration similar to P. keijii . Asakura & Paulay (2003) morphologically distinguished P. lemaitrei from P. keijii by three instead of one, longitudinal sulci on the lateral surface of the propodus of the right third pereopod. The present specimens with color variations of the right cheliped undoubtedly belong to P. keijii based on the morphological character ( Fig. 5F ).

Figures

FIGURE 3. Entire animal, dorsal view. A, Pylopaguropsis bellula Osawa & Okuno, 2007, male (sl 4.1 mm), RUMF-ZC-6042 (IE17); B, Pylopaguropsis fimbriata McLaughlin & Haig, 1989, ovigerous female (sl 4.4 mm), RUMF-ZC-6046 (IE179); C, Pylopaguropsis granulata Asakura, 2000, female (sl 4.8 mm), RUMF-ZC-6052 (HD2017-31); D, Pylopaguropsis keijii McLaughlin & Haig, 1989, male (sl 1.9 mm), RUMF-ZC-6055 (HD2017-87); E, Pylopaguropsis speciosa McLaughlin & Haig, 1989, ovigerous female (sl 3.7 mm), RUMF-ZC-6058 (SH104).

FIGURE 5. Pagurixus nomurai Komai & Asakura, 1995: female (sl 5.0 mm), RUMF-ZC-6038 (HD2017-65) (A, B); Pylopaguropsis granulata Asakura, 2000: female (sl 4.8 mm), RUMF-ZC-6052 (HD2017-31) (C–E); Pylopaguropsis keijii McLaughlin & Haig, 1989: male (sl 1.9 mm), RUMF-ZC-6055 (HD2017-87) (F). A, carpus of left cheliped, dorsal view; B, dactylus and propodus of left third pereopod, lateral view; C, right chela, dorsal view; D, carpus and merus of left second pereopod, lateral view; E, carpus and merus of left third pereopod, lateral view; F, propodus of right third pereopod, lateral view. Setae omitted from all illustrations. Scales equal 1.0 mm.