Progeryon mus Ng & Guinot, 1999

Komai, Tomoyuki & Tsuchida, Shinji, 2014, Deep-Sea decapod crustaceans (Caridea, Polychelida, Anomura and Brachyura) collected from the Nikko Seamounts, Mariana Arc, using a remotely operated vehicle “ Hyper-Dolphin ”, Zootaxa 3764 (3), pp. 279-316 : 309-310

Progeryon mus Ng & Guinot, 1999

( Figs. 26 F–I, 27, 28, 30D)

Progeryon guinotae ?— Sakai 1978: 11, figs. 21, 22, pl. 2, fig. B, C. Not Progeryon guinotae Crosnier, 1976 .

Progeryon mus Ng & Guinot, 1999: 686 , figs. 1, 2 [type locality: Nihoa Island, Hawaii, 441 m].—Ng et al. 2008: 84.

Material examined. RV “Natsushima”, NT10-13 cruise, ROV “Hyper-Dolphin”, dive #1165, Northeast Nikko Seamount, 23°06.679’N, 142°21.889’E, 556 m, 31 July 2010, slurp gun, 1 male (27.2 × 34.3 mm), JAMSTEC 018539-1; same dive, 23°06.687’N, 142°21.901’E, 548 m, 1 female (33.0 × 47.0 mm), JAMSTEC 081539 -2.

Coloration in life. Carapace, chelipeds and ambulatory legs generally light red-orange. Fingers of chelipeds black. Ambulatory legs whitish.

Distribution. Heretofore known only from Hawaii and Nintoku Seamount in the Emperor Seamount Chain, 610–1446 m. The present material greatly extends the geographical range of the species to the Northeast Nikko Seamount.

Ecology. The individuals were found to be slowly wandering on rock substrates ( Fig. 29 D).

Remarks. The genus Progeryon is represented by five species: P. guinotae Crosnier, 1976 from La Réunion ( Crosnier 1976); P. mararae Guinot & Richer de Forges, 1981 from French Polynesia, Sala y Gòmez and southwestern part of Nazca ridge (Guinot & Richer de Forges 1981; Zarenkov 1990; Parin et al. 1997); P. mus Ng & Guinot, 1999 from Hawaii and Nintoku Seamount (Ng & Guinot 1999); P. paucidens Bouvier, 1922 (type species) from off Morocco, eastern Atlantic ( Bouvier 1922); and P. vaubani Guinot & Richer de Forges, 1981 from Loyalty Islands, New Caledonia (Guinot & Richer de Forges 1981). The present specimens are identified with P. mus by the following key characters (Ng & Guinot 1999): anterolateral margin of carapace gently convex, without trace of lobes or fringe of long pubescence ( Fig. 28 A, B); anterior one-third of dorsal surface of carapace covered with small, well-defined, regularly spaced granules ( Fig. 28 A, B); outer surface of palm of male major cheliped glabrous ( Fig. 27 ); distal segment of male second gonopod noticeably curved inward ( Fig. 26 I). The first gonopod of the present male specimen ( Fig. 26 F–H) also agrees very well with the original description of P. m u s. However, we found that setation of the carapace, which has been considered to be species diagnostic (Ng & Guinot 1999), is considerably variable in the present material, and thus not reliable in species differentiation. In the male specimen, the dorsal surface of the carapace is apparently glabrous, though there are very short, worn pubescence remained on depressed parts ( Fig. 28 A). On the other hand, in the female specimen, the dorsal surface is entirely covered with very short pubescence, though granules on the anterior part are naked ( Fig. 28 B).

Figures

FIGURE 27. Progeryon mus Ng & Guinot, 1999, male (27.2 × 34.3 mm), JAMSTEC 081539 - 1, entire animal in dorsal view (in preservative).

FIGURE 28. Progeryon mus Ng & Guinot, 1999, carapace in dorsal view;. A, male (27.2 × 34.3 mm), JAMSTEC 081539 - 1; B, female (33.0 × 47.0 mm), JAMSTEC 081539 - 2, same lot.

FIGURE 29. Photographs in situ. A, Periclimenes sp. riding on the dorsal surface of an unidentified lophiid fish; B, three individuals of Heterocarpus laevigatus Spence Bate, 1888 and one specimen of Chaceon sp.; C, close up of one individual of Herterocarpus laevigatus. Those individuals were not collected.

FIGURE 26. A – E, Cyrtomaia micronesica Richer de Forges & Ng, 2007, male (42.5 × 50.5 mm), JAMSTEC 081529 - 2; F – I, Progeryon mus Ng & Guinot, 1999, male (27.2 × 34.3 mm), JAMSTEC 018539 - 1. A, basal segment of left antennal peduncle, anterior view; B, left first gonopod, lateral view; C, same, distal part, lateral view; D, same, mesial view; E, same, distal view; F, left first gonopod, ventral view; G, same, distal part, ventral view; H, same, dorsal (inner) view; I, left second gonopod, lateral view. Scale bars: 2 mm for A, B; 1 mm for C, D, F, I; 0.5 mm for E, G, H.