Goneplacoides, Castro, 2007

Castro, Peter, 2007, A reappraisal of the family Goneplacidae MacLeay, 1838 (Crustacea, Decapoda, Brachyura) and revision of the subfamily Goneplacinae, with the description of 10 new genera and 18 new species, Zoosystema 29 (4), pp. 609-774 : 692-693

Genus Goneplacoides n. gen.

Goneplax – Komatsu & Takeda 2003: 1243 (part).

TYPE SPECIES. — Goneplax marivenae Komatsu & Takeda, 2003 (by present designation and by monotypy; gender feminine).

SPECIES INCLUDED . — Goneplacoides marivenae ( Komatsu & Takeda, 2003) n. comb.

The genus is restricted to the Indo-West Pacific region.

ETYMOLOGY. — From -oides, Greek suffix for having the form of, and the generic name Goneplax , to indicate that although the species included in the new genus superficially resembles Goneplax in the shape of its carapace and its elongated eye peduncles, it actually belongs to a separate genus.

DESCRIPTION

Carapace ( Fig. 28A ) transversely rectangular, much wider than long; widest at conspicuous outer orbital teeth; front slightly deflected ventrally, sinuous, marked by 2 slight emarginations, small median projection between emarginations. Notch between front, inner edge of supraorbital border slight or absent; orbits wide, greatly expanded distally; supraorbital borders conspicuously sinuous; suborbital borders sinuous, with slight, obtuse inner tooth not visible dorsally; anterolateral borders short, straight. Dorsal surface of carapace smooth, moderately convex, without clear indication of regions. Outer orbital angle with conspicuous, acute tooth; acute anterolateral tooth on each side of carapace. Basal antennal article short, distalmost (third) article nearly reaches front. Eye peduncles ( Fig.28A ) relatively long, shorter than front (0.5 front width); cornea strongly reniform, dorsoventrally flattened, nearly divided into anterior and posterior portions.Anterior border of endostome well demarcated from buccal cavern, ridges faint but clearly defined. Third maxillipeds nearly completely close the buccal cavern. No obvious stridulating mechanism other than possible rubbing of proximal portion of cheliped merus (P1) against pterygostomial ridge. Thoracic sternum wide. Median sulcus on thoracic sternite 4 absent; sutures 4/5, 5/6, 7/8 interrupted medially, 6/7 complete ( Fig. 29 ; Komatsu & Takeda 2003: fig. 3a, as Goneplax marivenae ). Anterior end of sterno-abdominal cavity anterior to thoracic sternite 4. Cheliped fingers ( Fig. 28A ) long, slender, shovel-like, curved, shorter than elongated propodus; dactylus light in colour, without dark portion.Dorsal margins of ambulatory leg (P2-P5) meri ( Fig. 28A ) unarmed; dactyli of P2-P4 slender, without carina on each side, setose; P5 dorso-ventrally flattened, wide, without carina, bordered by long, simple setae ( Fig. 28A ). Male abdomen ( Komatsu & Takeda 2003: fig. 3b, as Goneplax marivenae , fig. 6a, b, as G. megalops ; Ng & Manuel-Santos 2007: fig. 9B, as “ Goneplax ” marivenae ) with 6 freely-movable somites plus telson, wide, somites 4-6 gradually decreasing in width from somite 3 (widest somite). Telson wide, only slightly longer than wide. Somite 3 covers space between P5 coxae, somite 2 narrower than somite 3; somites 1, 2 leave small portion of thoracic sternite 8 visible (Ng & Manuel-Santos 2007: figs 10B, 11B, as “ Goneplax ” marivenae ). G1 ( Komatsu & Takeda 2003: fig. 3c, d, as Goneplax marivenae , fig. 6c, d, as G. megalops ) long, slender, slightly sinuous, slightly broadened proximally. G2 ( Komatsu & Takeda 2003: fig. 3e, as Goneplax marivenae , fig. 6e, as G. megalops ) slender, slightly longer than G1, flagellum slightly longer than proximal part (peduncle), nearly coiled, tip pointed. Penis arising from P5 coxa ( Komatsu & Takeda 2003: fig. 3a, as Goneplax marivenae ; Ng & Manuel-Santos 2007: fig. 13B, as “ Goneplax ” marivenae ), moderate size; broad, soft proximal expansion. Female abdomen with 6 freely-movable somites, wide. Telson much wider than long. Somite 3 covers space between P5 coxae, somite 2 slightly narrower than somite 3; somites 1, 2 leave small portion of thoracic sternite 8 visible. Vulva ( Fig. 29 ) of mature females not expanded, small, round, extending from 5/6 suture to median portion of thoracic sternite 6, vulvar cover absent, covered by soft membrane.

REMARKS

The new genus consists of an Indo-West Pacific species originally described as Goneplax marivenae .

Several characters separate Goneplacoides n. gen. from Goneplax sensu stricto and from Hadroplax n. gen., Microgoneplax n. gen., Neogoneplax n. gen., Paragoneplax n. gen., and Singhaplax Serène & Soh, 1976 , the five Indo-West Pacific genera derived from Goneplax sensu lato (see Table 4).

Characteristic of Goneplacoides n. gen. is a G2 that is coiled distally ( Komatsu & Takeda 2003: figs 3e, 6e, as Goneplax megalops ), not straight or slightly curved as in the other genera.The male abdomen is wide and the vulva lacks a vulvar cover. The eye peduncle is shorter (0.5 of the front width) than in the remaining five genera. The propodus and dactylus of P2-P5 are broadened, fringed by conspicuous setae ( Fig. 28A ), and the dactylus lacks a carina on each side instead of having a more slender propodus and a long and slender dactylus with a carina on each side and no conspicuous setae as in Goneplax sensu stricto ( Fig. 27 ) and the other five genera ( Figs 28B, C ; 31 ; 34 ; 42 ; 46 ). The dactylus, however, is similarly broadened in Singhaplax platypoda n. sp. ( Fig. 37 ).

Figures

FIG. 28. — A, Goneplacoides marivenae (Komatsu & Takeda, 2003) n. comb., ♀, cl 7.6 mm, cw 11.6 mm, off southern coast of New Caledonia, SMIB 8, stn DW 177, 320-370 m (MNHN-B 29262); B, Neogoneplax renoculis (Rathbun, 1914) n. comb., ♂, cl 10.1 mm, cw 16.0 mm, South China Sea off Philippine Is, MUSORSTOM 3, stn CP 108, 188-195 m (MNHN-B 10334); C, Paragoneplax serenei (Zarenkov, 1972) n. comb., ♂, cl 8.6 mm, cw 14.9 mm, north of New Caledonia, BATHUS 1, stn CP 669 (MNHN-B 29327).

FIG. 29. — Goneplacoides marivenae (Komatsu & Takeda,2003) n. comb.,ovig.♀, cl 8.0 mm,cw 12.5 mm,New Caledonia,VOLSMAR, stn DW 59, 320 m (MNHN-B 29222), thoracic sternum and vulva.

FIG. 27. — A, Goneplax rhomboides (Linnaeus,1758), ♂, cl 21.6 mm, cw 34.7 mm, Shoalstone Point, Brixham, Devon,UK, D. George et al. coll., 18 m (BMNH 1981.539); B, Goneplax barnardi (Capart, 1951) n. comb., ♂, cl 14.1 mm, cw 25.1 mm, off northern coast of Angola, Campagne ZAIANGO-BIOL 2, stn CP 09, 360-367 m (MNHN-B 27933).

FIG. 31. — Neogoneplax costata n. sp., ♂ holotype, cl 10.4 mm, 19.1 mm, Balicasag I., off Panglao I., Philippine Is (ZRC 2004.0723).

FIG. 34. — Neogoneplax serratipes n. sp., ♂ holotype, cl 8.3 mm, cw 11.9 mm, off eastern coast of New Caledonia, HALIPRO 1, stn CP 851, 241-250 m (MNHN-B 29836).

FIG. 42. — Microgoneplax caenis n. sp., ♂ holotype, cl 4.2 mm, cw 7.1 mm, between Panglao and Pamilacan islands, Philippine Is, PANGLAO 2004, stn T27 (NMCR 27014).

FIG. 46. — Microgoneplax prion n. sp., ♂ holotype, cl 3.9 mm, cw 7.3 mm, Chesterfield Is, MUSORSTOM 5, stn DW 280 (MNHN-B 29318) (photo by P. Laboute, IRD, Nouméa).

FIG. 37. — Singhaplax platypoda n. sp.,pre-adult ♀ paratype,cl 3.3 mm,cw 6.0 mm,Futuna I., MUSORSTOM 7, stn DW 495 (MNHN-B 30068).