Nancyplax vossi Lemaitre, García-Gómez, Von Sternberg & Campos, 2001

CASTRO, PETER & NG, PETER K. L., 2010, Revision of the family Euryplacidae Stimpson, 1871 (Crustacea: Decapoda: Brachyura: Goneplacoidea), Zootaxa 2375 (1), pp. 1-130 : 82-84

Nancyplax vossi Lemaitre, García-Gómez, Von Sternberg & Campos, 2001

( Figs. 31 A-G; 32G-K)

Type material. Male holotype, 10.7 mm × 15.7 mm ( USNM 308995 ); 1 male paratype ( USNM 308996 ); 2 males paratypes ( USNM 308993 ); 1 male, 1 female paratypes ( USNM 308994 ) ; 2 ovigerous female paratypes ( UMML 32.8776 ); 2 males paratypes ( UMML 32.9079 ); 4 males paratypes ( UMML 32.9078 ); 1 male, 2 female paratypes ( UMML 32.8775 ); 1 male paratype (INVEMAR-CRU 2926).

Type locality. Off Venezuela, 11°06.3’N, 68°14.6’W, 95–132 m.

Material examined. Suriname. North of Paramaribo, 07°07’N, 55°08’W, Pillsbury , 11.07.1968: 1 male paratype, 12.1 mm × 17.2 mm, 1 female paratype, 12.1 mm × 17.9 mm ( USNM 308994 ) .

Remarks. See Remarks for genus.

Distribution. Western Atlantic, only known from the Caribbean Sea coasts of Colombia to Suriname.

Depth: 55–155 m.

Genus Platyozius Borradaile, 1902

Pseudozius (Platyozius) Borradaile, 1902: 243 .

Eucrate — Tesch 1918: 158 (part). — Ng et al. 2008: 78 [in list] (part).

Diagnosis. Carapace ( Figs. 33 , 34 ) trapezoidal, almost as wide as long, dorsal surface smooth without clear indication of regions except continuous, curved postorbital ridge between second anterolateral teeth parallel to front, orbits ( Fig. 34E ; dark colour in live specimens [ Fig. 33A–E ]; ridge less distinct in small individuals); anterolateral borders arched; front wide, straight, with small median notch, truncate margin but slight transverse sulcus in largest individuals. Three short, triangular teeth posterior to short, obtuse outer orbital angle; second anterolateral teeth largest, dorsally oriented, third smallest, particularly in largest individuals. Orbits moderately short (shorter than front), oblique, spherical ( Fig. 35A ); thin supraorbital border without notches (small notch may be present in small individuals); inner suborbital lobe, nearly straight margin without notches on thin suborbital border ( Fig. 35C ); eye peduncles short; large, spherical corneas ( Fig. 35A, C ). Basal antennal article mobile in small individuals, slightly mobile in larger ones, with disto-lateral process so that orbital hiatus is closed excluding antennal flagellum from orbit ( Fig. 35A, C ). Merus of third maxilliped auriculiform ( Fig. 35A, C ). Cheliped fingers moderately stout, slightly longer than swollen propodus ( Fig. 35B ), tips dark in live individuals ( Fig. 33 ); carpus with tooth on inner margin; scattered setae, no tomentum on anterior margin of carpus. Dorsal margins of ambulatory legs (P2–P5) meri, carpi, propodi unarmed, dactyli slender, smooth, setose; P5 propodus, dactylus proportionally short, flattened ( Figs. 33 ; 34 ), fringed with scattered, long setae, short spines. Thoracic sternum ( Fig. 35D, F, G ) wide; thoracic suture 2/3 complete, convex ( Fig. 35C, D ); 3/4 deep, short, interrupted; 4/5, 6/7, 7/8 interrupted, 5/6 complete ( Fig. 35G ); median groove on thoracic sternites 7, 8. Sterno-abdominal cavity of male deep, reaching only to median portion of sternite 4 ( Fig. 35F ). Press-button of male abdominal-locking mechanism as large tubercle near thoracic suture 4/5 (small tubercle present in pre-adult females). Male abdomen narrow, slender (T-shaped), lateral margins of somites 4–6 abruptly narrowing from somite 3 to narrow, pointed telson wide ( Fig. 35D, E ); somite 3 reaching inner margins of P5 coxae ( Fig. 35E ), outer margin with semi-circular projection that fits under thoracic sternite 7; no portions of thoracic sternite 8 exposed by closed abdomen, somite 2 transversely slightly shorter than somite 3. G1 long, slender, slightly sinuous, acuminate apex, with small denticles ( Figs. 35F ; 38A, B ); G2 less than one-third of G1, straight, apex with 2 processes: one long, tip obtuse; second much shorter, tip obtuse ( Fig. 38C ). Male genital opening (gonopore) coxal; coxo-sternal disposition of long penis ( Fig. 35F ), protected by concave posterior portion of thoracic sternite 7. Vulva ovoid, extending across anterior portion of sternite 6 close to median axis of thorax ( Fig. 35G ); covered by soft membrane, sternal vulvar cover absent.

Type species. Pseudozius (Platyozius) laevis Borradaile, 1902 (by monotypy, gender feminine).

Remarks. The only species in the genus was described as Pseudozius (Platyozius) laevis by Borradaile (1902: 243). The species, however, is clearly not a member of Pseudozius Dana, 1851 (family Pseudoziidae Alcock, 1898 ), as noted by Rathbun (1906: 861), who noticed the diagnostic “ridge above, behind, and parallel to the margin”, and adding that the anterior margin of the third maxilliped merus is not notched “as in typical Pseudozius ”. Its affinities with the Euryplacidae were recognized by Tesch (1918: 158), who synonymised Platyozius with Eucrate on account of its “general appearance”. Barnard (1950: 295) synonymised the species, without any comments, with Eucrate sulcatifrons Stimpson, 1858 , a junior synonym of E. crenata (De Haan, 1835) . This position was followed by Edmondson (1962: 4), whereas Dai et al. (1996: 247) and Ng et al. (2008: 78) treated it as a separate species of Eucrate . The genus Platyozius Borradaile, 1902 , is hereby resurrected and a diagnosis is given for the first time.

Species included. Platyozius laevis ( Borradaile, 1902) The genus is restricted to the Indo-West Pacific region.

Figures

FIGURE 31. Nancyplax vossi Lemaitre, García-Gómez, von Sternberg & Campos, 2001; A–D, male paratype (12.1 mm × 17.2 mm) (USNM 308994), Suriname; E–G, female paratype (12.1 mm × 17.9 mm) (USNM 308994), Suriname. A, overall view; B, frontal view showing orbits and antennae; C, third maxillipeds; D, anterior portion of male thoracic sternum and sterno-abdominal cavity; E, outer surface of right chela; F, male sterno-abdominal cavity and penis; G, female thoracic sternum and vulvae. Abbreviations: cx5 = coxa of fifth pereopod (P5); es7 = episternite 7; g = male gonopore; mg = median groove; p = penis; pb = press-button of male abdominal-locking mechanism; s4–s8 = thoracic sternites 4 to 8, respectively; v = vulva.

FIGURE 33. Platyozius laevis (Borradaile, 1902), colours in life. A, female (12.5 mm × 16.0 mm) (UF 1534), French Polynesia, Tuamotu Archipelago, Rangiroa Atoll; B, female (9.5 mm × 12.1 mm) (UF 1534), same location; C, specimen not located (LACM), Hawaiian Is., Northwest Hawaiian Islands, French Frigate Shoals; D, specimen not located, male, Vanuatu; E, F, male (6.9 mm × 8.6 mm) (LACM), Hawaiian Is., Northwest Hawaiian Islands, French Frigate Shoals. A– E, overall views; F, ventral view. Photo credits: A, B by Florida Museum of Natural History (UF); C–F by J. Martin (LACM).

FIGURE 34. Platyozius laevis (Borradaile, 1902); A, male holotype of Pseudozius (Platyozius) Borradaile, 1902 (5.0 mm × 6.0 mm) (UMZC), Maldives, Suvadiva Atoll (after Borradaile 1902: fig. 45); B, male holotype of Pseudozius (Platyozius) Borradaile, 1902 (5.0 mm × 6.0 mm) (UMZC), Maldives, Suvadiva Atoll; C, topotypic female of Pseudozius (Platyozius) Borradaile, 1902 (7.5 mm × 9.5 mm) (UMZC), Maldives; D, male (6.0 mm × 7.5 mm) (MNHN- B30534), Seychelles; E, female (12.5 mm × 16.0 mm) (UF 1534), French Polynesia, Tuamotu Archipelago, Rangiroa Atoll; F, female (6.3 mm × 7.7 mm) (MNHN-B30534), Seychelles. Abbreviation: pr = postorbital ridge. Photo credits: B, C by T.-Y. Chan (NTOU).

FIGURE 35. Platyozius laevis (Borradaile, 1902); A, female (11.0 mm × 14.0 mm) (ZRC 2004.0806), Bohol, Panglao Is., Balicasag I.; B, C, F, male (7.7 mm × 9.5 mm) (QM W28380), Hawaiian Is., Oahu, Halona Blowhole; D, E male (6.0 mm × 7.5 mm) (MNHN-B30534), Seychelles; F, female (12.5 mm × 16.0 mm) (UF 1534), French Polynesia, Tuamotu Archipelago, Rangiroa Atoll. A, frontal view showing orbits and antennae; B, outer surface of left chela; C, third maxillipeds; D, anterior portion of male thoracic sternum and abdomen; E, posterior portion of male thoracic sternum and abdomen; F, male sterno-abdominal cavity, G1, and penis; G, female thoracic sternum and vulvae. Abbreviations: a2, a3 = male abdominal somites 2 and 3, respectively; cx5 = coxa of fifth pereopod (P5); es7 = episternite 7; G1 = first male pleopod; p = penis; s4–s7 = thoracic sternites 4 to 7, respectively; v = vulva.

FIGURE 38. Gonopods of Platyozius, Psopheticoides, and Systroplax; carapace of Systroplax. A–C, Platyozius laevis (Borradaile, 1902), male (6.1 mm × 7.8 mm) (ZRC 2007.0707), Maldives, Laamu Atoll; D–F, Psopheticoides sanguineus Sakai, 1969, male (21.9 mm × 27.8 mm) (ZRC 2008.1357), Philippines, Bohol, Balicasag I.; G–J, Systroplax angusta (Rathbun, 1914); G, G1 (after Guinot 1989: fig. 39D); H, male (32.3 mm × 37.2 mm) (MNHN-B29377), Fiji; I, J, variation in anterolateral borders of carapace (after Guinot 1989: fig. 39A, C). A, B, D, E, right G1, dorsal view; C, F, H, right G2, dorsal view. Scale bars: A, D, 1.0 mm; B, E, 0.5 mm; C, F, H, 0.2 mm; G, 0.1 mm.