Psopheticus Wood-Mason, 1892

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 : 738-742

Genus Psopheticus Wood-Mason, 1892

Psopheticus Wood-Mason, 1891: 20 (nomen nudum).

Psopheticus Wood-Mason, 1892 : pl. 5, fig. 1. — Alcock 1899: 72 [diagnosis]; 1900: 292 [in list], 298 [in key], 308 (part). — Tesch 1918: 160 (part). — Sakai 1939: 555 [in key], 558 (part); 1976: 523 [in key], 529, 530 [key to species] (part). — Balss 1957: 1656 (part). — Guinot- Dumortier & Dumortier 1960: 142 [stridulating mechanism]. — Serène 1968: 90 [in list] (part). — Guinot 1969b: 528 [discussion] (part); 1971: 1081 [list of species] (part); 1990: 333 [revision] (part). — Hsueh & Huang 2002: 116 [in key] (part). — Karasawa & Kato 2003b: 130 [in list], 140 [in list], 141 [in table] (part). — Poore 2004: 438 (part). — Karasawa & Schweitzer 2006: 26 [in list], 40 (part).

TYPE SPECIES. — Psopheticus stridulans Wood-Mason, 1892 (by monotypy; gender masculine). Name placed in Official List of Names in Zoology (with the officially designated type species) in Opinion 85, Direction 37 (see Melville & Smith 1987: 158).

EXTANT SPECIES INCLUDED . — Psopheticus crosnieri Guinot, 1990 ; P. musicus Guinot, 1990 ; P. stridulans Wood-Mason, 1892 ; P. vocans Guinot, 1985 .

All species are restricted to the Indo-West Pacific region.

FOSSIL SPECIES INCLUDED ( Karasawa & Kato [2003b]). — Psopheticus shujenae (Hu & Tao, 1996) , Psopheticus sp. aff. P. stridulans Wood-Mason, 1892 .

SPECIES NOT INCLUDED IN PSOPHETICUS . — Psopheticus megalops Takeda, 1989 (incertae sedis).

DIAGNOSIS. — Carapace subquadrate, only slightly wider than long; front straight, often slightly concave, not marked by median notch or projection. Slight notch between front, inner edge of supraorbital border; orbits wide distally to accommodate reniform eyes, supraorbital borders conspicuously sinuous; suborbital borders rounded, with conspicuous, blunt inner tooth not visible dorsally; anterolateral borders straight or nearly straight so that fronto-orbital border as wide as or slightly narrower than maximum width of carapace at junction of anterolateral, posterolateral borders. Dorsal surface of carapace smooth, slightly convex, without clear indication of regions. Outer orbital teeth strongly projecting outwardly, flattened, triangular or leaf-like; typically acute anterolateral tooth on each side of carapace. Basal antennal article short, slender, distalmost (third) article reaches front. Eye peduncles relatively short, much shorter than front (0.3-0.4 front width); eyes reniform, dorso-ventrally flattened, cornea greatly expanded distally, nearly divided into anterior, posterior portions. Stridulating mechanism of subocular, sinuous pterygostomial crest plus tooth on outer (dorsal) margin of cheliped (P1) merus. Thoracic sternum wide. Median sulcus on thoracic sternite 4 absent; sutures 4/5, 5/6 interrupted medially, 6/7 almost complete, 7/8 complete ( Fig. 47 ; Guinot & Richer de Forges 1981b: fig. 12D; 1990: fig. 24). Anterior end of sterno-abdominal cavity anterior to thoracic sternite 4. Cheliped fingers ( Guinot 1990: figs 1-3, 19-23, 29-33, 35-38, 40) slender, shorter than propodus, not dark in colour; carpus with tooth on inner margin. Dorsal margin of merus of P2 ( Guinot 1990: figs 4-9, 41-43) with 1 subdistal tooth; dorsal margins of meri of P3-P5 ( Guinot 1990: figs 26-28, 34, 39) with several conspicuous, acuminate teeth; dorsal margins of carpi, propodi serrulated, with conspicuous teeth, or smooth; dactyli slender, carinated, setae absent. Male abdomen ( Guinot 1990: fig. 24; Hsueh & Huang 2002: fig. 12C) with 6 freely-movable somites plus telson, triangular, relatively 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 longer than somite 3 so that somites 1, 2 leave small, often triangular portion of thoracic sternite 8 visible ( Guinot & Richer de Forges 1981b: fig. 12D; Guinot 1990: fig. 24; Hsueh & Huang 2002: fig. 12G). G1 ( Zarenkov 1972: fig. 6-5; Guinot & Richer de Forges 1981b: fig. F; Guinot 1990: figs 44, 45, 47, 48, 50, 52, 53; Hsueh & Huang 2002: fig. 12D, H) long, stout, sinuous, proximally broadened, nearly triangular in overall shape, truncated tip. G2 ( Zarenkov 1972: fig. 6-5; Guinot & Richer de Forges 1981b: fig. G; Guinot 1990: figs 46, 49, 51, 54) slender, slightly longer than G1, flagellum slightly shorter than basal part, with basal spinules, slightly-expanded tip. Penis arising from P5 coxa, long, soft; narrow, soft proximal expansion. Female abdomen ( Hsueh & Huang 2002: fig. 12E) with 6 freely-movable somites, wide. Telson subovate. Somite 3 covers space between P5 coxae, somite 2 narrower than somite 3 so that somites 1, 2 leave small, often triangular portion of thoracic sternite 8 visible. Vulva of mature females ( Fig. 47 ) on margin of suture 5/6 posterior to large, oval depression on thoracic sternite 5; small, hook-like vulvar cover on posterior margin of vulva.

REMARKS

Alcock (1899: 73) commented on the close similarities between Psopheticus and Carcinoplax H. Milne Edwards, 1852 , adding that the genus should “perhaps ought rather to be regarded as a subgenus of Carcinoplax ”. Serène (1968: 90) included Psopheticus in a list of genera questionably included in the subfamily Carcinoplacinae . Guinot (1990) revised Psopheticus and recognized seven species, including four new ones. Števčić (2005) placed Psopheticus sensu lato in the tribe Psopheticini independent from the tribe Carcinoplacini of the subfamily Carcinoplacinae . Psopheticus sensu lato actually consists of two groups of different species as far as the reproductive structures are concerned. A new genus, Exopheticus n. gen., is erected herein to include one of the two groups.

Species of Psopheticus possess a conspicuous soundmaking, or stridulating, mechanism that consists of a pterygostomial crest on inflated subocular and subhepatic regions that rubs against a large tooth on the distal margin of the P1 merus (see Alcock 1900: 309; Guinot 1990: 364, figs 55-57; Guinot- Dumortier & Dumortier 1960). The mechanism is found in both sexes and its function remains unknown.

Psopheticus megalops Takeda, 1989 , which was described from Japan, clearly does not belong in Psopheticus or in Exopheticus n. gen. Its inclusion in Psopheticus by Takeda (1989: 174) was based on “rather arbitary [sic] and tentative” reasons, mostly on the quadrate shape of its carapace. The morphology of its pointed G1 and G2 ( Takeda 1989: fig. 17C-F) suggests its exclusion from the Goneplacidae sensu stricto.

KEY TO SPECIES OF PSOPHETICUS WOOD- MASON, 1892

1. Ambulatory legs (P2-P5) carpi and propodi smooth, without teeth ............................ 2

— Ambulatory legs (P2-P5) carpi or propodi (or both carpi and propodi) with teeth ..... 3

2. Outer orbital and anterolateral teeth triangular, foliaceous, straight; western Pacific Ocean in distribution ............................................................................................... P. musicus

— Outer orbital teeth typically slender and oriented outwardly; anterolateral teeth typically slender; western Indian Ocean in distribution .............................................. P. crosnieri

3. P3-P5 propodi smooth to the naked eye ..................................................... P. stridulans — P3-P5 propodi serrated, with small, clearly demarcated teeth .......................... P. vocans

Psopheticus stridulans Wood-Mason, 1892 ( Fig. 47 )

Psopheticus stridulans Wood-Mason, 1892 : pl. 5, fig. 1 [Andaman Sea]. — Alcock 1894: 402; 1899: 73; 1900: 309 [in key], 309; 1902: 260, 274, fig. 52 [Andaman Sea]. — Doflein 1904: 118, 236, 306 (table), pl. 30, fig. 4 [Andaman Sea]. — Tesch 1918: 161 [in key], 161 [ Indonesia]. — Guinot-Dumortier & Dumortier 1960: 126, 144 [stridulating mechanism]. — Serène 1968: 90 [in list]. — Guinot 1969b: 528; 1971: 1081 [in list]; 1990: 334 [in key], 334, 335 [in table]; figs 1, 4-6, 55. — Karasawa & Kato 2003b: 130 [in list]. — Karasawa & Schweitzer 2006: 27 [in list].

Psopheticus insolitus Guinot, 1990: 334 [in key], 335 [in table], 358, figs 40-43, 57 [ Indonesia].

Not “? Psopheticus stridulans ” – Guinot 1969b: 528, figs 81, 82 (= Psopheticus crosnieri Guinot, 1990 ).

Not Psopheticus stridulans – Sakai 1955: 108, fig. 2; 1956: 46 [in list]; 1976: 530, pl. 193, fig. 3. — Zarenkov 1972: 231, figs 2, 6-5. — Miyake 1991: 149, 220 [in list], pl. 50, fig. 2. — Ikeda 1998: 15, 43, 138, pl. 58. — Muraoka 1998: 47 [in list] [ Japan]. — Hsueh & Huang 2002: 126 [in key], 126, figs 8E, 12. — Takeda et al. 2006: 205 [in list] [ Japan] (= Psopheticus musicus Guinot, 1990 ).

TYPE MATERIAL. — Psopheticus stridulans Wood-Mason, 1892: 344-402 m, 2 ♂♂, 1 ♀ syntypes, unknown deposit ( Zoological Survey of India, Kolkata [Calcutta]?) ; ♀ topotype, cl 13.8 mm, cw 19.2 mm ( BMNH 1899.1.20.13) (see Guinot 1990: 337) .

Psopheticus insolitus Guinot, 1990 : ♀ holotype, cl 19.9 mm, cw 25.6 mm (MNHN-B 12630).

TYPE LOCALITY. — Psopheticus stridulans: Andaman Sea , 677- 785 m.

Psopheticus insolitus : Indonesia, Makassar Strait, CORIN- DON 2, stn CH 211, 313 m.

MATERIAL EXAMINED. — Andaman Sea. Indian Museum leg., 677-767 m, 1 ♀ ( BMNH 99.1.20.13).

Indonesia. Makassar Strait, CORINDON 2, stn CH 211, 00°12.8’S, 117°53.7’E, 313 m, 31.X.1980, ♀ holotype of Psopheticus insolitus ( MNHN-B 12630).

Lombok, Siboga Expedition , stn 38, 07°35.4’S, 117°28.6’E, 521 m, 1.IV.1899, 1 ♂ ( ZMA De 240141).

Tanimbar Is, KARUBAR, stn CP 35, 06°08’S, 132°45’E, 390-502 m, 27.X.1991, 1 ♂, 1 ♀ ( MNHN-B 29175 ). — Stn CC 40, 07°46’S, 132°31’E, 443-468 m, 28.X.1991, 1 ♂, 1 ♀ ( MNHN-B 29170 ). — Stn CP 69, 08°42’S, 131°53’E, 356-368 m, 2.XI.1991, 1 ♂, 3 ♀♀ ( MNHN-B 29168 ). — Stn CP 70, 08°41’S, 131°47’E, 413- 410 m, 2.XI.1991, 1 ♂, 2 ♀♀ ( MNHN-B 29167 ). — Stn CP 71, 08°38’S, 131°44’E, 477-480 m, 2.XI.1991, 1 pre- adult ♀ ( MNHN-B 29173 ). — Stn CP 77, 08°57’S, 131°27’E, 352- 346 m, 3.XI.1991, 3 ♂♂ ( MNHN-B 29169 ) ; 1 ♀ ( MNHN-B 30057 ). — Stn CP 78, 09°06’S, 131°24’E, 295- 284 m, 3.XI.1991, 2 ♂♂ ( MNHN-B 29176 ). — Stn CP 83, 09°23’S, 131°00’E, 285-297 m, 4.XI.1991, 2 ♂♂, 2 ♀♀ ( MNHN-B 29174 ) .

Chesterfield Islands. CORAIL 2, stn DE 15, 20°50.72’S, 160°55.76’E, 590- 580 m, 21.VII.1988, 1 ♂, 1 ♀ ( MNHN-B 29181).

New Caledonia. BATHUS 4, stn CP 910, 18°59.32’S, 163°08.47’E, 560-608 m, 5.VIII.1994, 2 ♂♂, 1 ♀ ( MNHN-B 29189).

DISTRIBUTION. — Andaman Sea ( Alcock 1900; Doflein 1904) and Indonesia (Makassar Strait, Lombok,Tanimbar Is; Tesch 1918; Guinot 1990, as P. insolitus ) and now from Chesterfield Is and New Caledonia. Depth: 284- 785 m. Also collected from a station at a depth of 720-900 m ( Tesch 1918: 161).

REMARKS

The relatively large number of specimens of P. stridulans examined has permitted the study of individual variation. Guinot (1990) used the presence of a single dorsal, subdistal tooth in each P2 merus as a diagnostic character of the species. Nevertheless, one of the three topotype specimens, a female, was shown to actually have two teeth, the second being small and almost median ( Guinot 1990: fig. 4). There is a great deal of variation in the ornamentation of the ambulatory legs (P2-P5). Most specimens had one dorsal, subdistal tooth on each P2 meri but there were some exceptions. A pre-adult female from Indonesia (cl 8.1 mm, cw 10.2 mm, MNHN-B 29173) had three teeth on the right leg and two (plus a short one) on the left leg. The carpus of the right P5 showed one tooth while that of the left P5 had one tooth and five short ones, which may categorize it as “spinulose,” another diagnostic character of the species. Another exception was a large male also from Indonesia (cl 24.8 mm, cw 31.7 mm, MNHN-B 29175) with three teeth on each P2 merus. One small male from the same station (cl 11.8 mm, cw 15.0 mm, MNHN-B 29175) had two teeth on each P2 merus while a small female (cl 10.9 mm, cw 14.5 mm, MNHN-B 29175) had one tooth on the right merus but two on the left one. Two females (cl 23.8 mm, cw 29.2 mm, cl 23.8 mm, cw 29.8 mm; MNHN-B 29168) had three dorsal teeth on each P2 merus.

Revision of Goneplacinae ( Crustacea, Brachyura)

The P3-P5 carpi typically showed two teeth. In several small specimens (male, cl 16.1 mm, cw 19.9 mm, MNHN-B 29170), however, the P4 carpi showed one large tooth and several smaller ones. Two females (cl 23.8 mm, cw 29.2 mm, cl 23.8 mm, cw 29.8 mm; MNHN-B 29168) showed the same ambulatory leg ornamentation, three dorsal teeth on P2, as P. insolitus Guinot, 1990 , from Indonesia, which was described from only one female specimen from Indonesia.

All of the specimens with exceptions described above showed the acute, slender anterolateral teeth and the broad, triangular outer orbital teeth that characterize the species. Psopheticus insolitus was described as a separate species because of its unusual ambulatory leg ornamentation, a situation that has also been found in specimens of P. stridulans . The anterolateral teeth of the holotype of P. insolitus , however, are unusually blunt ( Guinot 1990: fig. 40) in contrast to the acuminate ones of P. stridulans . Since the shapes of the outer orbital and anterolateral teeth are seemingly more stable characters than the ornamentation of the ambulatory legs, the morphology of the single specimen of P. insolitus is still puzzling. It is felt, however, that there are no clear, valid reasons to consider it a member of a separate species.

As pointed out by Guinot (1990: 337), specimens from Japan ( Sakai 1955: 108, fig. 2; 1976: 530, pl. 193, fig. 3) and the South China Sea ( Zarenkov 1972: 231, figs 2, 6-5) identified as P. stridulans do not belong to this species but to P. musicus Guinot, 1990 , on account of the smooth, unarmed carpi and propodi of the ambulatory legs. A figure given by Sakai (1955: fig. 2), however, does show teeth on the right P3-P4 and the left P3 but none are shown in another specimen ( Sakai 1976: pl. 193, fig. 3). No teeth are shown in illustrations of other specimens from Japan ( Ikeda 1998: 138, pl. 58) and Taiwan ( Hsueh & Huang 2002: figs 8E, 12). The presence of P. musicus in Japan and Taiwan has now been confirmed (see below) but not that of P. stridulans .

The vulva of mature females ( Fig. 47 ) has a small, hook-like vulvar cover on its posterior margin.

Figures

FIG. 47. — Psopheticus stridulans Wood-Mason, 1892, ♀, cl 22.8 mm, cw 28.1 mm, Tanimbar Is, Indonesia, KARUBAR, stn CP 77, 352-346 m (MNHN-B 30057), thoracic sternum and vulva, vulvar cover, and remains of sperm plug.