Cheiroplatea pumicicola Forest, 1987

Komai, Tomoyuki & Chan, Tin-Yam, 2016, “ Symmetrical ” hermit crabs of the family Pylochelidae (Crustacea: Decapoda: Anomura) collected by the “ BIOPAPUA ” and “ PAPUA NIUGINI ” expeditions in the Papua New Guinea, with descriptions of two new species, Zootaxa 4088 (3), pp. 301-328 : 310-312

Cheiroplatea pumicicola Forest, 1987

( Fig. 1 B)

Cheiroplatea pumicicola Forest, 1987a: 108 , figs. 3b, 5e, 23a–i, 24a–e, 31a–f, pls. VI E, F, IX [type locality: Kermadec Ridge, New Zealand, 490–590 m]; 1987b: 316, fig. 3.—Forest & McLaughlin 2000: 36, figs. 6, 7.—Lemaitre et al. 2009: 5.— McLaughlin & Lemaitre 2009: 176.

Cheiroplatea mitoi .—McLaughlin & Lemaitre 2009: 174 (in part).

Material examined. SALOMON 2, stn CP 2176, SW of Russel, Solomon Sea, 09°09.24’S, 158°59.11’E, 600–875 m, 21 October 2004, 1 male (sl 3.7 mm), identified with C. mitoi by McLaughlin & Lemaitre (2009), MNHN-IU- 2014-10289 (formerly Pg 7940).

BIOPAPUA, stn CP 3670, N of Rabaul, 04°06’S, 151°56’E, 497–500 m, 24 September 2010, 2 males (sl 3.2, 3.3 mm), 4 ovigerous females (sl 3.3–3.8 mm), MNHN-IU-2011-1127; stn CP 3671, N of Labaul, 04°04’S, 151°56’E, 585–601 m, 24 September 2010, 2 males (sl 3.2, 3.5 mm), 1 female (sl 3.7 mm), 3 ovigerous females (sl 3.8–4.3 mm), MNHN-IU-2011-962; stn CP 3679, Kimbe Bay, 05°21’S, 150°45’E, 490–715 m, 25 September 2010, 2 males (sl 2.7, 3.4 mm), MNHN-IU-2011-3046; stn CP 3679, Kimbe Bay, 05°21’S, 150°45’E, 490-715 m, 25 September 2010, 1 male (sl 3.2 mm), MNHN-IU-2011-1367; stn DW 3680, off Vitu Islands, 04°36’S, 149°27’E, 615–647 m, 27 September 2010, 1 male (sl 3.4 mm), MNHN-IU-2011-3374; stn CP 3681, off Vitu Islands, 04°38’N, 149°27’E, 564–712 m, 27 September 2010, 1 female (sl 3.8 mm), MNHN-IU-2011-2631; stn CP 3682, off Vitu Island, 04°38’S, 149°28’E, 515–812 m, 27 September 2010, 1 female (sl 3.8 mm), MNHN-IU-2011- 3430; stn DW 3683, off Vitu Island, 04°37’S, 149°28’E, 291 m, 27 September 2010, 1 male (sl 3.6 mm), MNHN- IU-2014-12694; stn CP 3737, off Lancasay Island, 08°15’S, 150°45’E, 587 m, 9 October 2010, 1 male (sl 3.7 mm), MNHN-IU-2011-3264; same data, 1 male (sl 3.3 mm), MNHN-IU-2011-1643; stn CP 3739, off Woodlark Island, Solomon Sea, 09°09’S, 152°15’E, 503–546 m, 10 October 2010, 1 ovigerous female (sl 4.6 mm), MNHN-IU- 2011-3197; stn CP 3740, off Woodlark Island, 09°12’S, 152°16’E, 556–645 m, 10 October 2010, 1 ovigerous female (sl 4.4 mm), MNHN-IU-2011-2427; stn CP 3743, off Woodlark Islands, 09°11’S, 152°16’E, 540–585 m, 10 October 2010, 1 female (sl 4.1 mm), 6 ovigerous females (sl 3.6–5.3 mm), MNHN-IU-2011-1901.

PAPUA NIUGINI, stn CP 4007, SE of Tuam Island, Solomon Sea, 06°04’S, 148°09’E, 460–528 m, 11 December 2012, 2 ovigerous females (sl 3.7, 4.3 mm), MNHN-IU-2013-14429; stn CP 4008, SE of Tuam Island, Solomon Sea, 06°04’S, 148°10’E, 500–555 m, 11 December 2012, 1 female (sl 3.6 mm), MNHN-IU-2013-14425; same data, 1 female (sl 3.3 mm), 2 ovigerous females (sl 3.9, 4.2 mm), MNHN-IU-2013-14428; stn CP 4009, SE of Tuam Island, Solomon Sea, 06°04’S, 148°12’E, 550–575 m, 11 December 2012, 5 females (sl 3.7–4.6 mm), 3 ovigerous females (sl 3.4–4.6 mm), MNHN-IU-2013-14423.

Description. See Forest (1987a: 108), Forest & McLaughlin (2000: 36) and McLaughlin & Lemaitre (2009: 176).

Size. Largest male sl 3.7 mm, largest female sl 5.3 mm, ovigerous females sl. 3.4–5.3 mm.

Coloration in life. Body and appendages entirely whitish, terga of pleonites with weak iridescence; corneas opaque ( Fig. 1 B).

Distribution. Previously known from Solomon Islands, Vanuatu, New Caledonia, New Zealand; 291–715 m. Newly recorded from Papua New Guinea, 291–812 m.

Habitat. Cavities in pumice rock (Forest & McLaughlin 2000; McLaughlin & Lemaitre 2009; this study).

Remarks. The present material agrees generally with the previous descriptions of Cheiroplatea pumicicola in most diagnostic aspects (Forest 1987a; Forest & McLaughlin 2000; McLaughlin & Lemaitre 2009), except for the armature of the meri of the second pereopods. In the identification key to the species of Cheiroplatea, McLaughlin & Lemaitre (2009) used the armature of the meri of the second pereopods in differentiating C. pumicicola from C. scutata : “ventral margins of meri of second pereopods each with few spines or spinules, dorsal margins unarmed” in C. pumicicola , whereas “ventral margins of meri of second pereopods unarmed, dorsal margins each with 2 spinules” in C. scutata . However, in the present 29 specimens with intact second ambulatory legs (57 leg samples were available), the number of ventral spinules ranges from zero to eight and, of dorsal spinules, also from zero to eight. Actually, 10 specimens have ventrally unarmed meri of both sides. Therefore, it must be concluded that the spination of the meri of the second pereopods is not useful as a key character. Nevertheless, C. pumicicola can be easily distinguished from C. scutata by the following features: the rostrum is marginally unarmed in C. pumicicola , whereas armed with five spinules in C. scutata ; the ocular peduncle is cone-shaped, terminating in an acute or subacute point, in C. pumicicola , but in contrast, it is noticeably inflated at the basal part with a rounded cornea in C. scutata ; the palm of the cheliped is armed with numerous, scattered small spines in C. pumicicola , rather than armed with elongate spines arranged in irregular longitudinal rows in C. scutata .

In having an acutely pointed ocular peduncle, C. pumicicola more closely resembles C. cenobita and C. mitoi than C. scutata . Cheiroplatea cenobita differs from C. pumicicola in the less developed armature on the palms of chelipeds, consisting only of microscopic tubercles, instead of numerous spinules in C. pumicicola , and the unarmed dorsal surface of the propodus of the second pereopod (versus armed with a row of tiny spines in C. pumicicola ). Cheiroplatea mitoi is distinguished from C. pumicicola by the different shape of the rostrum and the armature of the cheliped palms. In C. mitoi , the rostrum is rounded and reaches the lateral projections of the shield, whereas in C. pumicicola , it is obtusely triangular or broadly rounded, not reaching the lateral projections; the spinules on the midline on the cheliped palm are elongate, distinctly longer than the spinules on the other area in C. mitoi , whereas those median spinules are subequal or slightly longer than the others in C. pumicicola . Furthermore, the carpus of the third pereopod is unarmed on the dorsal margin in C. mitoi , rather than armed with a row of spinules in C. pumicicola .

Reexamination of the specimen from the Solomon Sea (MNHN-IU-2014-10289), referred to as Cheiroplatea mitoi by McLaughlin & Lemaitre (2009), has revealed that the specimen agrees with C. pumicicola , rather than C. mitoi , in all diagnostic characters mentioned above.

Figures

FIGURE 1. A, Cheiroplatea laticauda Boas, 1926, entire animal in dorsal view, BIOPAPUA, stn CP 3646, male (sl 8.7 mm), MNHN-IU- 2011 - 3885; B, Cheiroplatea pumicicola Forest, 1987, entire animal in dorsal view, BIOPAPUA, stn CP 3737, male (sl 3.7 mm), MNHN-IU- 2011 - 3264.