Psopheticoides sanguineus Sakai, 1969: 274 Serène & Vadon 1981: 120 Takeda 1982: 19 Miyake 1991: 220 Castro 2007: 620 Ng et al . 2008: 78 Carcinoplax Tesch 1918: 154 Rathbun, 1914b: 142 Serène 1968: 89 Sakai 1969: 269 Serène & Lohavanijaya 1973: 62 Guinot 1989: 273 Chen 1998: 266 Carcinoplax H. Milne Edwards, 1852 Revision of the family Euryplacidae Stimpson, 1871 (Crustacea: Decapoda: Brachyura: Goneplacoidea) CASTRO, PETER NG, PETER K. L. Zootaxa 2010 2010-02-26 2375 1 1 130 4PLBF Sakai, 1969 Sakai 1969 [151,626,1719,1745] Malacostraca Euryplacidae Psopheticoides Animalia Decapoda 88 89 Arthropoda species sanguineus  ( Figs. 36A–G; 38D–F; 39C)      Psopheticoides sanguineus Sakai, 1969: 274, figs. 16b, 17a, a', b, 18b, c; 1976: 528, fig. 282, pl. 192, fig. 3 [ Japan]. —  Serène & Vadon 1981: 120, 123, 127 [ Philippines] —  Takeda 1982: 19[list]; 2001: 248 (as Propheticoides[ sic]), 251, 258 [list] [ Japan]. —  Miyake 1991: 220[in list] [ Japan]. —  Castro 2007: 620[discussion] [ Philippines, Tonga] —  Ng et al. 2008: 78, fig. 63 [colour photograph] [in list].   Type material.  Male holotype( USNM 125888); 1 female paratype(unknown status)    Typelocality. Japan, Kyushu, Tosa Bay, off Mimase,  100–150 m.  Material examined.   Philippines. Bohol. Balicasag I., off Panglao I.,  200–300 m, tangle nets of local fishermen, 12.2000:  2 females( ZRC 2001.0366); 50–500 m, 28.11.2001:  4 males, 1 female, 2 ovigerous females ( ZRC 2001.0539); 200–300 m, 06.2002:  1 male, 1 female( ZRC 2002.0651); 25– 30.07.2003:  8 males, 1 female, 17.7 mm× 22.3 mm( ZRC 2004.0752);   02.03.2004: 2 ovigerous females ( ZRC 2004.0713); 11.2003:  1 male, 2 females, 3 ovigerous females ( ZRC); 12.2003:  1 male( ZRC 2008.1359); 02.2004: 1 ovigerous female ( ZRC 2008.1360); 05.2004:  2 males( ZRC).   Panglao I., Maribojoc Bay,  100–300 m, T. J. Arbastocoll., 11.2003 –04.2004: 1 ovigerous female ( ZRC 2008.1361);   28.05.2004: 1 male, 21.9 mm× 27.8 mm( ZRC 2008.1357);  07.2004 –05.2005: 1 ovigerous female, 1 female( ZRC 2008.1362).   FIGURE 36.  Psopheticoides sanguineus Sakai, 1969; male (21.3 mm × 26.5 mm) (ZRC 2004.0752), Philippines, Bohol, Panglao. A, overall view; B, frontal view showing orbits and antennae; C, third maxillipeds; D, outer surface of right chela; E, anterior portion of male thoracic sternum and abdomen; F, posterior portion of male thoracic sternum and abdomen; G. female sternum and vulvae. Abbreviations: a1–a3 = male abdominal somites 1, 2, 3, respectively; cx5 = coxa of fifth pereopod (P5); s4–s7 = thoracic sternites 4 to 8, respectively; vc = sternal vulvar cover.  PANGLAO 2004: stn. P1, Natocoll.,  30.05.2004: 1 male, 22.0 mm × 26.7 mm, 1 female, 20.1 mm× 25.3 mm( MNHN-B29728).  Vanuatu.SANTO 2006: no data: 1 male, 7.8 mm× 9.8 mm( ZRC 2009.0974).    Tonga.BORDAU 2: stn. DW 1634, 21°45’S, 175°20’W,  321–322 m,  20.06.2000: incomplete specimen ( MNHN-B29808).   Diagnosis.Reniform eyes ( Fig. 36B). Orange-red circle on dorsal surface of carapace ( Fig. 39C).   Remarks.A large but damaged and incomplete specimen from Tonga(MNHN-B29808) clearly shows the characteristic carapace, including the colour spot.  Colour pattern.A distinctive orange-red circle fringed by a yellow-white border located on the cardiac region of the carapace ( Fig. 39C; Ng et al. 2008: fig. 63). The rest of the carapace and the ambulatory legs are orange-red.   Distribution.Western Pacific from Japanto the Philippines, Vanuatu, and Tonga. Depth: 50– 322 m.  Genus  Systroplax n. gen.     Carcinoplax—  Tesch 1918: 154(part). —  Rathbun, 1914b: 142. —  Serène 1968: 89[in list] (part). —  Sakai 1969: 269(part). —  Serène & Lohavanijaya 1973: 62, 63 [key to species] (part). —  Guinot 1989: 273(part). —  Chen 1998: 266[key to species] (part). [not  CarcinoplaxH. Milne Edwards, 1852]   Diagnosis.Carapace ( Fig. 37A) suboctagonal, nearly round; front long, nearly straight (outer edges slightly arched in large individuals), marked by small median notch; transverse sulcus along margin; notch between front, supraorbital border. Orbits short, spherical ( Fig. 37B); supraorbital borders short, arched, with 2 notches; suborbital borders arched, 2 very small notches in larger individuals; large, granular, ventrally oriented inner suborbital tooth ( Fig. 37B, C); eye peduncles short, granular; large, spherical corneas. Anterolateral borders arched, 2 short, obtuse anterolateral teeth; posterolateral borders long, arched. Dorsal, ventral surface of carapace with short, spherical granules ( Fig. 37B, C), strongly convex, without clear indication of regions. Outer orbital angle with very short, triangular tooth; 2 obtuse, small anterolateral teeth on each side of carapace, first larger (much reduced or absent in large individuals, particularly second tooth; Fig. 38I, J). Basal antennal article immobile, with distolateral process so that orbital hiatus is closed excluding antennal flagellum from orbit ( Fig. 37B, C). Outer (ventral) surface of third maxilliped carpus, merus granular, anteroexternal margin of merus auriculiform ( Fig. 37C). Subhepatic, pterygostomian regions, pterygostomian crest granular. Thoracic sternum ( Fig. 37E, G) wide, granular outer margins; thoracic suture 2/3 complete, straight ( Fig. 37E, G); 3/4 deep, short, interrupted; 4/5, 5/6, 6/7, 7/8 interrupted ( Fig. 37G); median groove on thoracic sternites 7, 8 ( Fig. 37G). Sterno-abdominal cavity of male deep, reaching median portion of sternite 4 ( Fig. 37E). Press-button of male abdominal-locking mechanism as tubercle near thoracic suture 4/5 (presence in pre-adult females unknown). Anteroexternal margin of third maxilliped merus auriculiform. Cheliped (P1) propodus, carpus, merus granular (inner surface of propodus relatively smooth); fingers moderately stout, slightly shorter than swollen propodus, tips darker in colour ( Fig. 37D). Carpus with long, blunt tooth on distal, inner margin; merus with large, blunt tooth on inner surface near anterior margin. Dorsal margins of ambulatory legs (P2–P5) meri, carpi, propodi unarmed, dactyli slender, smooth, setose; P5 dactyli, propodi proportionally short, flattened, fringed with scattered, long setae, spines. Maleabdomen narrow, slender (Tshaped), lateral margins of somites 4–6 abruptly narrowing from somite 3 to transversely narrow, pointed telson ( Fig. 37E); somite 3 reaching inner margins of P5 coxae, outer end fitting under episternite 7; somite 2 transversely shorter than somite 3 but no portions of thoracic sternite 8 exposed by closed abdomen ( Fig. 37F). G1 long, slender, slightly sinuous, acuminate apex, with small denticles ( Fig. 38G). G2 less than onethird of G1, straight, with 2 processes: one long, tip acute; second much shorter, small, lobe-like ( Fig. 38H). Malegenital opening (gonopore) coxal; coxo-sternal disposition of long penis with very broad, soft proximal expansion, protected by concave posterior portion of thoracic sternite 7. Female abdomen relatively narrow, not covering outer portions of thoracic sternum, with six freely-mobile somites. Telson broadly triangular, wider than long. Somites 1, 2 cover space between P5 coxae, only small portion of each P5 condyle of sternite 8 left exposed by closed abdomen ( Fig. 37F). Vulva of mature females ovoid, extending across median portion of thoracic sternite 6 close to median axis of thorax ( Fig. 37G); covered by soft membrane, sternal vulvar cover absent.    Typespecies.  Carcinoplax angustaRathbun, 1914(by present designation, gender feminine).   Etymology.From systremma, Greek for anything aggregated, generally a ball or round object, in reference to the diagnostic round shape of the carapace of the typespecies, and plax, Greek for “plate” or “tablet”, which is derived from the generic name  Carcinoplax(from karkinos, Greek for crab), to denote that the species included in the new genus was formerly included in the latter.   Remarks.Although the carapace shape is superficially similar to two species assigned to the family Goneplacidae sensu stricto(i.e.  Carcinoplax tenuidentata Castro, 2007, and  Pycnoplax bispinosa(Rathbun, 1914); Castro 2007: figs. 5, 13B),  Systroplax  n. gen.clearly belongs to the Euryplacidae ( Castro 2007: 623). The male abdomen is slender, with a narrow and pointed telson ( Fig. 37E), and the G1, also slender, is much longer than the G2. Although the shape of the abdomen of goneplacids varies, it is typically broad and triangular and a similarly shaped telson (i.e. Castro 2007: figs. 4B, 16B), never narrow as in the Euryplacidae. The G 1 in  CarcinoplaxH. Milne Edwards, 1852, is never as slender as in euryplacids and the apex is much wider, never acuminate (e.g. Castro 2007: fig. 2), or thick and stout as in  Pycnoplax Castro, 2007(e.g. Castro 2007: fig. 16C). A G2 much shorter than the G1, however, is present in three goneplacid genera ( Castro 2007). The vulva of  Systroplax  n. gen.is typical of euryplacids, relatively small with thick margins and no sternal vulvar cover, in contrast to the much expanded vulva of  Carcinoplax(e.g. Castro 2007: fig. 1), or the vulva covered by a sternal vulvar cover of  Pycnoplax(e.g. Castro 2007: fig. 15). In contrast to most euryplacids, thoracic suture 5/6 is interrupted, a character nevertheless shared with  Nancyplaxand  Xenocrate( Table 1).  Species included.  Systroplax angusta(Rathbun, 1914)The genus is restricted to the Indo-West Pacific region. [340,720,1989,2015] USNM Male 88 89 USNM 125888 1 Maale holotype [198,970,151,178] Japan Mimase 125 Kyushu Tosa Bay 89 90 1 holotype Balicasag I. & Panglao I. Philippines 250 Bohol 89 90 1 Bohol [350,684,226,252] ZRC Philippines 89 90 ZRC 2001.0366 2 2 Bohol ZRC Philippines 89 90 ZRC 2001.0539 5 1 4 Bohol [656,1094,263,290] ZRC Philippines 89 90 ZRC 2002.0651 2 1 1 Bohol ZRC Philippines 89 90 ZRC 2004.0752 9 1 8 Bohol [718,1322,301,327] 2004-02-03 ZRC Philippines 89 90 ZRC 2004.0713 1 Bohol [151,723,338,364] ZRC Philippines 89 90 3 2 1 Bohol [854,1164,338,364] ZRC Philippines 89 90 ZRC 2008.1359 1 1 Bohol ZRC Philippines 89 90 ZRC 2008.1360 1 Bohol [572,750,376,402] ZRC Philippines 89 90 2 2 Bohol ZRC Panglao I. & T. J. Arbasto 200 11.2003 Maribojoc Bay 7 -4.2004 89 90 ZRC 2008.1361 1 [306,1051,450,476] 2004-05-28 ZRC 89 90 ZRC 2008.1357 1 1 ZRC 7.2004 7 -5.2005 89 90 ZRC 2008.1362 1 1 2004-05-30 ZRC Nato Vanuatu Vanuatu 90 91 MNHN-B29728, ZRC 2009.0974 3 1 2 2000-06-20 Tonga 322 -21.75 Tonga 1262 -175.33333 90 91 MNHN-B29808 1