Oxypleurodon papuense, Lee & Forges & Ng, 2019

Lee, Bee Yan, Forges, Bertrand Richer De & Ng, Peter K. L., 2019, Deep-sea spider crabs of the family Epialtidae MacLeay, 1838, from Papua New Guinea, with a redefinition of Tunepugettia Ng, Komai & Sato, 2017, and descriptions of two new genera (Crustacea: Decapoda: Brachyura: Majoidea), Zootaxa 4619 (1), pp. 1-44 : 8

Oxypleurodon papuense n. sp.

( Figs. 1D , 3 A–C, 5E–H)

Material examined. Holotype: male (18.3 × 12.6 mm) (MNHN-IU-2015-228) [photographed], stn DW4286, north of Laughlan Islands , Solomon sea, 09°12’S 153°55’E, 306–365 m, coll. MADEEP Expedition, 30 April 2014.

Diagnosis. Relatively large species (carapace length 18.3 mm). Carapace pyriform. Pseudorostral spines short, slightly curved, strongly diverging to form prominent V-shape. Carapace with several raised plates; 2 elongate supraorbital plates; postorbital plate fused with hepatic plate forming L-shape plate; gastric region with 3 granules above 1 rounded mesogastric plate; 2 epibranchial plates; 2 elongate plates on each side of carapace; 1 large rounded cardiac plate; posterior region of carapace with raised thick plate, with blunt posterior tooth medially ( Figs. 1D , 3A ). Antennal flagellum slightly longer than or equal in length to pseudorostral spines. Basal antennal article longer than broad, narrow, fused with carapace; distal angle blunt. Buccal frame covered by third maxilliped. Pterygostomial region with 1 raised plate on outer margin ( Fig. 3B ). Chelipeds stout, slightly shorter than P2; propodus slightly inflated, nearly equal in length to fingers; carpus with carinate on both margin; merus triangular in cross-section. Ambulatory legs slender; P2 longest. Male thoracic sternum depressed anteriorly; sternites 3 and 4 narrow, constricted anteriorly, widest at base. Male pleon triangular, with telson and 6 somites all free. G1 straight, slightly constricted near distal third, distal tip sharp ( Fig. 5 E–H).

Coloration. Coloration of live specimen is whitish with the anterior part of the carapace and the chelae pink ( Fig. 1D ).

Etymology. The name of this species is named after the country, Papua New Guinea, where it was collected.

Remarks. At approximately 18 mm in carapace length, Oxypleurodon papuense n. sp. is relatively large for members of this genus. The comparable species are O. forte Lee, Corbari & Richer de Forges, 2015 , from the South China Sea, O. karubar Richer de Forges, 1995 , from Indonesia, O. luzonicum ( Rathbun, 1916) , and O. sanctaeclausi Richer de Forges & Ng, 2009 , from the Philippines, and O. wilsoni Richer de Forges & Poore, 2008 , from Western Australia (cf. Richer de Forges 1995: figs. 2, pl. 2 A, C; Richer de Forges & Poore 2008: fig. 1b; Richer de Forges & Ng 2009a: figs. 1A, 11A; Lee et al. 2015: figs. 2A, 3A). All these species have a round cardiac plate, large epibranchial plates, and there are three gastric granules. These species, however, have sharp branchial plates directed outwards (cf. Richer de Forges 1995: figs. 2, pl. 2 A, C; Richer de Forges & Poore 2008: fig. 1b; Richer de Forges & Ng 2009a: figs. 1A, 11A; Lee et al. 2015: figs. 2A, 3A). Oxypleurodon papuense n. sp., however, only has a rounded branchial plate ( Figs. 1D , 3A ).

Oxypleurodon papuense n. sp. is currently only known from its type locality, Papua New Guinea.

Figures

FIGURE 1. Color in life. A, Griffinia takedai Richer de Forges & Ng, 2012, male (13.6 × 10.2 mm) (MNHN-IU-2013-3021), Papua New Guinea; B, Laubierinia carinata (Griffin & Tranter, 1986), male (24.7 × 16.0 mm) (MNHN-IU-2014-8128), Papua New Guinea; C, Oxypleurodon alisae n. sp., holotype, male (14.0 × 9.3 mm) (MNHN-IU-2015-227), Papua New Guinea; D, O. papuense n. sp., holotype, male (18.3 × 12.6 mm) (MNHN-IU-2015-228), Papua New Guinea; E, O. sp. 1, juvenile male (6.0 × 4.2 mm) (ZRC 2018.1478, ex. MNHN-IU-2017-11835), Papua New Guinea; F, Stegopleurodon planirostrum Richer de Forges & Ng, 2009, male (14.0 × 9.2 mm) (MNHN-IU-2015-64), Papua New Guinea.

FIGURE 3. Oxypleurodon papuense n. sp., holotype, male (18.3 × 12.6 mm) (MNHN-IU-2015-228), Papua New Guinea. A, overall dorsal view; B, overall ventral view; C, lateral view of carapace.

FIGURE 5. A–D, Oxypleurodon alisae n. sp., holotype, male (14.0 × 9.3 mm) (MNHN-IU-2015-227), Papua New Guinea, left G1. A, ventral view; B, ventral view of distal portion; C, dorsal view; D, dorsal view of distal portion. E–H, O. papuense n. sp., holotype, male (18.3 × 12.6 mm) (MNHN-IU-2015-228), Papua New Guinea, left G1. E, ventral view; F, ventral view of distal portion; G, dorsal view; H, dorsal view of distal portion.