Entricoplax, 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 : 654-657

Genus Entricoplax n. gen.

Carcinoplax H. Milne Edwards, 1852: 164 (part). — Ortmann 1894: 685 [in key] (part). — Tesch 1918: 154 (part). — Balss 1922: 135; 1957: 1656 (part). — Sakai 1939: 555 [in key], 555; 1969: 269; 1976: 523 [in key] (part). — Barnard 1950: 282 [in key], 286 (part). — Serène 1968: 89 [in list] (part). — Guinot 1969b: 520, 524; 1971: 1081 [in list of species]; 1989: 273 (part). — Chen 1984: 188; 1998: 266 (part). — Serène & Lohavanijaya 1973: 62, 63 [in key to species] (part). — Dai et al. 1986: 366 [in key to species] (part). — Dai & Yang 1991: 394 [in key to species] (part). — Davie 2002: 193 (part). — Karasawa & Kato 2003b: 130 [in list], 140 [in list], 141 [in table] (part). — Karasawa & Schweitzer 2006: 26 [in list] (part).

TYPE SPECIES. — Cancer (Curtonotus) vestitus de Haan, 1833 (by present designation; gender feminine).

SPECIES INCLUDED . — Entricoplax vestita (de Haan, 1833) n. comb.

The genus is restricted to the Yellow and East China seas and the Pacific Ocean off Japan.

ETYMOLOGY. — From entrichos, Greek for “hairy”, in reference to the characteristic abundant setae on the carapace, chelipeds (P1), and ambulatory legs (P2-P5), and plax, Greek for “plate” or “tablet”, which is derived from the generic name Carcinoplax (from karkinos, Greek for crab) to denote that the type species of the new genus was formerly included in Carcinoplax sensu lato.

DESCRIPTION

Carapace ( Shen 1932: fig. 63; Sakai 1976: pl. 190, fig. 3, as Carcinoplax vestita ), transversely rectangular, much wider than long; widest at junction of anterolateral, posterolateral borders; front lamellar, concave, strongly deflexed, not marked by median notch or projection. Notch between front, inner edge of supraorbital border slight; orbits long, wide, expanded distally; supraorbital borders bilobed, with conspicuous tubercle-like process; suborbital borders long, rounded, without inner tooth; anterolateral borders convex. Dorsal surface of carapace covered by abundant setae, moderately convex, without clear indication of regions. Outer orbital angle with short prominence; 2 short anterolateral teeth on each side of carapace. Basal antennal article short, subquadrate, distalmost (third) article reaches front. Eye peduncles ( Shen 1932: fig. 64, as C. vestita ) relatively long (0.5 front width), dorsal surface with conspicuous setae; cornea reniform, dorso-ventrally flattened, much expanded distally, nearly divided into anterior, posterior portions. Anterior border of endostome well demarcated from buccal cavern, ridges clearly defined. Third maxillipeds completely close the buccal cavern. No obvious stridulating mechanism other than possible rubbing of proximal portion of cheliped (P1) merus against pterygostomial ridge. Thoracic sternum wide. Sulcus on thoracic sternite 4 conspicuous but interrupted medially ( Fig. 11 ); sutures 4/5, 5/6, 6/7, 7/8 interrupted medially. Anterior end of sterno-abdominal cavity anterior to thoracic sternite 4. Cheliped fingers ( Shen 1932: fig. 65a; Sakai 1976: pl. 190, fig. 3, as C. vestita ) slender, nearly triangular, shorter than propodus, tips light in colour; large, blunt teeth. Carpus with tooth on inner margin. Dorsal margins of meri, carpi, propodi of ambulatory legs (P2-P5) unarmed, covered with setae; dactyli slender, smooth, numerous thick setae. Male abdomen ( Shen 1932: fig. 65b, as C. vestita ) with 6 freely-movable somites plus telson, narrowly triangular; somite 1 long (longest somite), wide; somites 4-6 gradually decreasing in width from somite 3 (widest somite). Telson wider than long. Somite 3 covers space between P5 coxae, somite 2 narrower than somite 3 so that somite 2 leaves relatively large portion of thoracic sternite 8 visible. G1 ( Takeda & Miyake 1968: fig. 5f; Dai & Yang 1991: fig. 192-2, as C. vestita ) long, slender, thin, straight, only slightly broadened proximally; pointed, thin tip. G2 ( Takeda & Miyake 1968: fig. 5g, as C. vestita ) slender, slightly longer than G1, flagellum slightly shorter than proximal part (peduncle), slightly-expanded tip with lateral spinule. Penis arising from P5 coxa, moderate size; slightly-expanded, soft proximal expansion. Female abdomen ( Shen 1932: fig. 65c, as C. vestita ) with 6 freely-movable somites, wide.Telson wider than long. Somite 1 long, wide; somite 2 covers space between P5 coxae, thoracic sternite 8 not visible. Vulva of mature females ( Fig. 11 ; Doi & Watanabe 2006: fig. 1) greatly expanded, extending from suture 5/6 to suture 6/7, covered by soft membrane, thickened inner margins but vulvar cover absent.

REMARKS

The new genus is being described for Carcinoplax vestita , which was described as Cancer (Curtonotus) vestitus de Haan, 1833 . Guinot (1989: 314) listed the species among eight non-revised species of Carcinoplax that eventually proved to belong in other genera.

Diagnostic of Entricoplax n. gen. is a supraorbital border that is long and bilobed, with orbits expanded to accommodate the reniform eyes (in contrast to Carcinoplax , where the supraorbital bor- der is curved or sinuous, with orbit not expanded and distal portion of the cornea is rounded), a concave, conspicuously deflexed front (straight in Carcinoplax ), suborbital border long and without an inner tooth (shorter and with a short inner tooth in Carcinoplax ), somite 1 of male and female abdomens conspicuously long, much longer than somite 2 in both sexes and longer than somite 3 in the male abdomen (short in Carcinoplax ), and large area of thoracic sternite 8 of males is left uncovered (usually completely or partially covered by somite 2 in Carcinoplax ), basal antennal article short and subquadrate (slender and longer in Carcinoplax ), and short anterolateral teeth (longer and more conspicuous in most species of Carcinoplax ). Also characteristic of E. vestita n. comb., the only species included in the new genus, is the relatively long and dense setae that cover the carapace and pereopods.

The G1, G2, and vulva of Entricoplax n. gen. are nevertheless similar to those of Carcinoplax . The G1 is slender, straight, and thin, being close to that of C. longimana , the type species of the genus (see Takeda & Miyake 1968: fig. 5; Dai & Yang 1991: fig. 192-2, as C. vestita ; Kim 1973: fig. 162B, as C. vestitus ). The G2 is slightly longer than the G1, shorter than the proximal part (peduncle), and has a slightly-expanded tip with one lateral spinule, similar to the G2 of some species of Carcinoplax . The vulva ( Fig. 11 ) is expanded and lacks a vulvar cover as in Carcinoplax .

Entricoplax vestita (de Haan, 1833) n. comb. ( Fig. 11 )

Cancer (Curtonotus) vestitus de Haan, 1833: 51 , pl. 5, fig. 3 [ Japan].

Curtonotus vestitus – MacLeay 1838: 61. — Krauss 1843: 33 (not E. vestita (de Haan, 1833) n. comb. = Pilumnus longicornis Hilgendorf, 1878 ).

Curtonotus vestitus – White 1847: 37 [in list].

Carcinoplax vestitus – H. Milne Edwards 1852: 164. — Parisi 1918: 91 [ Japan]. — Sakai 1939: 557, 722, fig. 64, pl. 66, fig. 5; 1940: 42, 45 [in lists]; 1956: 46 [in list]; 1965: 167, pl. 83, fig. 2; 1969: 269 [in list] [ Japan]. — Kamita 1941a: 235, 241 [in list]; 1941b: 138, fig. 75 [ Korea]. — Imaizumi 1960: 221; 1961: 187 [fossils, Japan]. — Park 1964: 17 [in list] [ Korea]. — Serène 1968: 89 [in list]. — Kim 1970: 16 [in list]; 1973: 407, 636, figs 160, 162, pl. 85, fig. 123a-d; 1977: 206 [in list] [ Korea]. — Lee & Hong 1970: 1, figs 1-5 [larvae, Korea]. — Kim & Kim 1982: 141, 151 [in list] [ Korea].

Pilumnoplax vestita – Miers 1886: 227 [in list]. — Ortmann 1894: 687 [ Japan]. — Tesch 1918: 155 [in list], 156 [in key]. — Yokoya 1933: 191, 213 [ Japan]. — Sakai 1934: 312; 1935: 182, fig. 93 [ Japan]. — Kamita 1936: 32 [in list] [ Korea].

Pilumnoplax vestita var. sexdentata Miers, 1886 : xxx, xxxi, xxxvii, xlviii, 227, 229 [ Japan].

Carcinoplax vestita – Rathbun 1902b: 24 [ Japan]. — Shen 1932: 110, figs 63-65, pl. 5, fig. 1; 1948: 106 [in list] [Yellow and East China seas]. — Barnard 1950: 287 [in key], 288. — Miyake 1961: 21 [in list] [ Japan]; 1991: 145, 219 [in list], pl. 49, fig. 1 [ Japan]. — Miyake et al. 1962: 129 [in list] [ Japan]. — Takeda & Miyake 1968: 564, fig. 5f, g [ Japan]. — Guinot 1969b: 524 [discussion]; 1989: 314 [in list]; 1971: 1081 [in list]. — Holthuis & Sakai 1970: 279 [ Japan]. — Serène & Lohavanijaya 1973: 62 [in list], 63 [in key]. — Sakai 1976: 524 [in key], 525, pl. 190, fig. 3 [ Japan]. — Kikuchi & Miyake 1978: 42 [in list] [ Japan]. — Chen 1984: 188 [in key], 189 (as C. vistita [sic]), 197, pl. 1, fig. 8 [Yellow and East China seas]; 1998: 266 [in key]. — Dai et al. 1986: 366 [in key], 370, fig. 192-2, pl. 53, fig. 8 [Yellow Sea]. — Yamaguchi et al. 1987: 22, pl. 9, fig. 10 [ Japan]. — Dai & Yang 1991: 394 [in key], 398, fig. 192-2, pl. 53, fig. 8 [Yellow Sea]. — Rikuta 1991: 21 [ Japan]. — Yamaguchi & Baba 1993: 431, fig. 152 [type material]. — Takeda 1995: 139 [in list] [ Japan]. — Muraoka 1998: 47 [in list] [ Japan]. — Ito & Honma 2001: 29 [in list] [ Japan]. — Davie 2002: 194 [in list]. — Karasawa & Kato 2003b: 130 [in list]. — Doi & Watanabe 2006: 13, figs 1-3 [ Japan]. — Ikeda & Takeda 2006: 179 [in list] [ Japan]. — Takeda et al. 2006: 204 [in list] [ Japan]. — Karasawa & Schweitzer 2006: 26 [in list].

Pilumnoplax vestitus – Stebbing 1910: 313 [in list]. — Balss 1922: 136.

TYPE MATERIAL. — Japan, P. F. von Siebold & H. Bürger coll., ♀ lectotype ( RMNH D 311); ♂ dry paralectotype, cl 13.2 mm, cw 18.0 mm ( MNHN 2958); 2 ♂♂, 2 ♀♀ dry paralectotypes ( RMNH D 42274); mouthparts of paralectotype ( RMNH D) (see Yamaguchi & Baba 1993: 431, fig. 152; 2003: 51; Fransen et al. 1997: 111).

TYPE LOCALITY. — Japan.

MATERIAL EXAMINED. — Japan. Honshu, off Yokosuka, Challenger, 18 m, 1 pre-adult ♀ ( BMNH). — 34°18.0’N, 133°35.0’E, Challenger, stn 233B, 27 m, 1 pre-adult ♀ ( BMNH).

Sagami Bay?, T. Sakai leg., 1 ♀ ( BMNH 1961.6.5.82). Miyako Bay, Iwate, off Hei-gawa rivermouth, 15-20 m, T. Komai coll., 24.V.1995, 1 ♂, 2 ♀♀ ( CBM-ZC 1690 ). Unknown localities, P. F. von Siebold & H. Bürger coll., 1823-1834, ♂ dry paralectotype ( MNHN-B 2958 ) ; 1 ♂, 1 pre-adult ♀ ( MNHN-B 24259 ) .

China. Tuandao, off Qindao, from tangle nets of local fishermen, 30-50 m, P. K. L. Ng coll., 23-25.VIII.2001,

Revision of Goneplacinae ( Crustacea, Brachyura)

4 ♂♂ ( ZRC 2002.0494). — Amoy, C. J. Shen leg., 1 ♂, 1 ♀ ( BMNH 1935.3.19.117).

DISTRIBUTION. — Yellow and East China seas, east (Pacific Ocean) coast of Japan (see map in Chen 1984: fig. 8, as C. vestita ). Depth: 15- 110 m.

REMARKS

The unique characters of Entricoplax vestita n. comb., which sets it apart from the species of Carcinoplax , where it was traditionally included , are discussed in the description of Entricoplax n. gen. (see above). Entricoplax vestita n. comb. appears to be restricted to the Yellow and East China seas and the Pacific Ocean coast of Japan. A record from South Africa is the result of a misidentification (see Barnard 1950: 288, as C. vestita ). It has also been listed, almost certainly as an error or oversight, as occurring in Australia ( Balss 1922: 136; Barnard 1950: 288; Sakai 1976: 525; Davie 2002: 194, as C. vestita ).

Two small pre-adult females (cl 6.3 mm, cw 8.9 mm, cl 8.7 mm, cw 12.2 mm, BMNH) from Japan identified as Pilumnoplax vestita var. sexdentata by Miers (1886: 229) clearly belong to E. vestita n. comb., the only difference being that their anterolateral teeth are more pronounced than those of adult individuals.

Figures

FIG. 11. — Entricoplax vestita (de Haan, 1833) n. comb., ♀, cl 28.8 mm, cw 38.8 mm, Miyako Bay, Japan, 15-20 m (CBM-ZC 1690), thoracic sternum and vulva.