Euryplacidae

Key to genera of Euryplacidae View in CoL

1. Male abdomen clearly narrow, slender, T-shaped ( Fig. 1C, D View FIGURE 1 ); Indo-West Pacific distribution (but one species introduced in the Mediterranean Sea).................................................................................................................................. 2

– Male abdomen clearly triangular ( Fig. 1A, B View FIGURE 1 ) or proportionally wide, not slender, T-shaped; tropical and subtropical Atlantic and Eastern Pacific distribution ................................................................................................................... 10

2. Orbits, eye peduncles short, eye peduncles as short as or slightly longer than corneas .............................................. 3

– Orbits, eye peduncles long, eye peduncles much longer than corneas ......................................................................... 7

3. Corneas reniform, dorsoventrally flattened ( Fig. 36B View FIGURE 36 ); G1 with arrowhead-shaped apex ( Fig. 38D, E View FIGURE 38 ) ...................... ................................................................................................................................................................. Psopheticoides View in CoL

– Corneas spherical, not dorsoventrally flattened (e.g. Figs. 3B View FIGURE 3 ; 16C View FIGURE 16 ); G1 with acuminate apex (e.g. Figs. 14A; 20A, D View FIGURE 20 ) .................................................................................................................................................................................. 4

4. Sulcus posterior to orbits extending along anterior border of carapace between anterolateral borders ( Fig. 34E View FIGURE 34 ) ........ ....................................................................................................................................................................... Platyozius View in CoL

– No sulcus extending along anterior border of carapace between anterolateral borders (if sulcus present it is short, not extending between anterolateral borders) ..................................................................................................................... 5

5. P5 dactylus, propodus proportionally slender (e.g. Fig. 2 View FIGURE 2 ), with only scattered setae; conspicuous tomentum on chelipeds ................................................................................................................................................................. Eucrate View in CoL

– P5 dactylus, propodus proportionally wide, with many long setae ( Figs. 37A View FIGURE 37 ; 49A View FIGURE 49 ); no conspicuous tomentum on chelipeds ...................................................................................................................................................................... 6

6. Each side of carapace with two short, inconspicuous anterolateral teeth ( Figs. 37A, B View FIGURE 37 ; 38I, J View FIGURE 38 ) ....... Systroplax View in CoL n. gen.

– Each side of carapace with two acute, conspicuous anterolateral teeth ( Fig. 49A, B View FIGURE 49 ) ................................... Xenocrate View in CoL

7. One short anterolateral tooth posterior to outer orbital tooth on each side of carapace (e.g. Figs. 21A View FIGURE 21 ; 23A View FIGURE 23 ), transverse depression (postorbital ridge) posterior to each orbit (except in one species) ....................... Henicoplax View in CoL n. gen.

– Two or three anterolateral teeth posterior to outer orbital tooth on each side of carapace, carapace without transverse depression posterior to orbits ....................................................................................................................................... 8

8. First anterolateral tooth minute, inconspicuous, leaving wide, straight margin between outer orbital tooth and second (largest) anterolateral tooth ( Fig. 28A, D View FIGURE 28 ), thus having only two large anterolateral teeth posterior to outer orbital tooth on each side of carapace ...................................................................................................................... Heteroplax View in CoL

– First anterolateral tooth large, conspicuous, thus having three large anterolateral teeth posterior to outer orbital tooth on each side of carapace ............................................................................................................................................... 9

9. Anteroexternal margin of third maxillipeds auriculiform ( Fig. 41A View FIGURE 41 ) ................................................ Trissoplax View in CoL n. gen.

– Anteroexternal margin of third maxillipeds angular ( Figs. 29D View FIGURE 29 ; 30C View FIGURE 30 )........................................................ Machaerus View in CoL

10. Outer orbital tooth short, inconspicuous ( Fig. 31A–C View FIGURE 31 ) ................................................................................. Nancyplax View in CoL

– Outer orbital tooth conspicuous ................................................................................................................................. 11

11. Conspicuous (abundant, long) tomentum on merus, carpus, propodus of cheliped (e.g. Figs. 44A, D View FIGURE 44 ; 48A, C View FIGURE 48 )....... 12

– Short tomentum on chelipeds, never long, abundant throughout cheliped ................................................................ 13

12. Two anterolateral teeth posterior to outer orbital tooth on each side of carapace ( Figs. 44A View FIGURE 44 ; 45A View FIGURE 45 ) ....... Trizocarcinus View in CoL

– Only one anterolateral tooth posterior to outer orbital tooth on each side of carapace ( Figs. 47A, B View FIGURE 47 ; 48A View FIGURE 48 ) ................ .............................................................................................................................................................. Villoplax View in CoL n. gen.

13. Two broad, short anterolateral teeth posterior to outer orbital tooth on each side of carapace (e.g. Figs. 16A View FIGURE 16 ; 17A View FIGURE 17 ); corneas spherical (e.g. Fig. 16C View FIGURE 16 ) ..................................................................................................................... Euryplax View in CoL

– One acute, long anterolateral tooth posterior to outer orbital tooth on each side of carapace ( Fig. 19A View FIGURE 19 ); corneas reniform, dorsoventrally flattened ( Fig. 19A, B View FIGURE 19 ) .................................................................................................... Frevillea View in CoL

Genus Eucrate De Haan, 1835

Cancer (Eucrate) De Haan, 1835: 36 (type species Cancer (Eucrate) crenatus De Haan, 1835 , by monotypy; gender feminine) [Opinion 85, Direction 37].

Cancer (Galene) — White, 1849: 144.

Pilumnoplax Stimpson, 1858: 93 View in CoL (39); 1907: 90 (type species Pilumnoplax sulcatifrons Stimpson, 1858 , subsequent designation by Rathbun, 1918; gender feminine).

Eucrate View in CoL — Haswell 1882b: 86 [diagnosis]. — De Man 1887: 88 [discussion]. — Alcock 1900: 292 [in list], 298 [in key], 298. — Tesch 1918: 157. — Stebbing 1920a: 238; 1920b: 268. — Barnard 1950: 282 [in key], 295. — Balss 1922a: 137; 1957: 1656. — Sakai 1939: 555 [in key], 561; 1976: 523 [in key], 535. — Campbell 1969: 117. — Guinot 1969b: 508 [discussion]; 1971: 1080 [list of species]. — Serène & Lohavanijaya 1973: 70 [list of species]. — Takeda & Shimazaki 1974: 60 [discussion]. — Tirmizi & Ghani 1996: 76 [diagnosis]. — Davie, 2002: 198 [diagnosis]. — Karasawa & Kato 2003a: 151 [in list]; 2003b: 130 [in list], 139 [in list]. — Ng & Castro 2007: 44 [in list], 45 [discussion]. Ng et al. 2008: 78, 79 [in list]. — De Grave et al. 2009: 33 [in list].

Diagnosis. Carapace (e. g. Figs. 2 View FIGURE 2 ; 3A View FIGURE 3 ) trapezoidal, almost as wide as long, dorsal surface smooth without clear indication of regions or with variously developed setose grooves, depressions (median frontal notch, shallow depression posterior to each orbit extending laterally to anterolateral teeth), convex; anterolateral borders arched; front wide, straight, lamelliforn or truncate, typically with median notch ( Fig. 3B–D View FIGURE 3 ; absent or inconspicuous in E. alcocki , E. formosensis ). Two or 3 typically low teeth (second may be acute, dorsally salient) posterior to rounded or triangular outer orbital tooth. Short (shorter than front), wide, spherical orbits ( Fig. 3B View FIGURE 3 ); 2 notches on thick supraorbital border; short median lobe, outer notch on thick suborbital border ( Fig. 3C, D View FIGURE 3 ); eye peduncles short, as long as or slightly longer than corneas ( Fig. 3B View FIGURE 3 ); large, spherical corneas. Basal antennal article immobile, with disto-lateral process so that orbital hiatus is closed excluding antennal flagellum from orbit ( Fig. 3B–D View FIGURE 3 ; Campbell 1969: fig. 1C). Anteroexternal margin of third maxilliped merus angular or auriculiform. Cheliped fingers moderately stout, slightly longer than swollen propodus, dark or light in colour; carpus with tooth on inner margin; dense, short tomentum on anterior margin of carpus in most species. Dorsal margins of ambulatory legs (P2–P5; Fig. 3A View FIGURE 3 ) meri, carpi, propodi unarmed (granular in some species), dactyli slender, smooth, setose; P5 propodus slender, dactylus long, slender, with shallow longitudinal depression, fringed with scattered, long setae. Thoracic sternum wide ( Fig. 3C, G View FIGURE 3 ); thoracic suture 2/3 complete, convex, close to anterior margin of sternum ( Fig. 3C View FIGURE 3 ); 3/4 deep, short, interrupted; 4/5, 6/7, 7/8 interrupted, 5/6 complete ( Figs. 3G View FIGURE 3 ; 11F View FIGURE 11 ); median groove on thoracic sternites 7, 8 ( Fig. 3G View FIGURE 3 ). Sterno-abdominal cavity of male deep, nearly reaching anterior margin of sternite 4 ( Fig. 11E View FIGURE 11 ). Press-button of male abdominal-locking mechanism ( Fig. 11E View FIGURE 11 ) as tubercle near thoracic suture 4/5 (small tubercle present in pre-adult females). Male abdomen ( Fig. 3C View FIGURE 3 ) narrow, slender (T-shaped), lateral margins of somites 4–6 abruptly narrowing from somite 3 to transversely narrow, pointed telson; somite 3 reaching inner margins of P5 coxae ( Fig. 3F View FIGURE 3 ); no portions of thoracic 8 exposed by closed abdomen, somite 2 transversely almost as long as somite 3. G1 long, slender, sinuous (straight in E. tripunctata Campbell, 1969 ; Fig. 15J), acuminate apex, with small denticles (e.g. Figs. 11E View FIGURE 11 ; 14A, B, D, E); G2 less than one-third of G1, apex with 2 unequal acute or obtuse processes (e.g. Fig. 14C, F). Male genital opening (gonopore) coxal ( Guinot 1969b: fig. 35); coxo-sternal disposition of long penis, protected by concave posterior portion of thoracic sternite 7 ( Fig. 11E View FIGURE 11 ). Vulva ( Fig. 3G View FIGURE 3 ) ovoid, extending across anterior portion of sternite 6 close to median axis of thorax; covered by soft membrane, sternal vulvar cover absent.

Type species. Cancer (Eucrate) crenatus De Haan, 1835 (by monotypy, gender feminine) [Opinion 85, Direction 37].

Remarks. De Man (1887: 88) stated that the genus Eucrate “is a very natural one, distinguished not only by its entire physiognomy, but also by the structure of the external antennae”. Heteroplax was nevertheless considered a junior synonym of Eucrate by some authors, although most preferred to keep both as independent genera (see Remarks for Heteroplax below). Eucrate , presumed to be in the Goneplacinae , was included in the Euryplacinae by Guinot (1969b: 508). Campbell (1969) revised the genus but essentially restricted his work to Australian species. His work left several unanswered questions, particularly the status of the poorly understood E. sulcatifrons Stimpson, 1858 .

The G1 and G2 respectively, are remarkably similar among the species of Eucrate . The long and slender G1 is invariably sinuous ( Fig. 11E View FIGURE 11 ; straight in E. tripunctata ; Fig. 15J), with small denticles along the distal portion and an acuminate apex (e.g. Fig. 14A, B, D, E). Sakai (1976: 537) nevertheless points out differences in the extension of the spinular portion of the G1 of three species. These differences, as well as the relative size and distribution of the spinules, are not clear cut and appear to be related to the size of the individuals. The short G2 is also very similar among the Eucrate species (e.g. Fig. 14C, F), and in most details, among all euryplacids.

Table 1 summarizes differences between Eucrate and the other genera of the Euryplacidae .

Species included.

Eucrate alcocki Serène , in Serène & Lohavanijaya, 1973

= Eucrate maculata Yang & Sun, 1979

Eucrate crenata (De Haan, 1835)

= Pilumnoplax sulcatifrons Stimpson, 1858

Eucrate dorsalis ( White, 1849)

= Eucrate hamiltoni McCulloch, 1908

= Galene ? laevimanus Lucas , in Jacquinot & Lucas, 1853

Eucrate formosensis Sakai, 1974

Eucrate indica n. sp.

Eucrate sexdentata Haswell, 1882

Eucrate solaris Yang & Sun, 1979

Eucrate tripunctata Campbell, 1969

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

Species excluded from Eucrate De Haan, 1835 :

Eucrate affinis Haswell, 1882 [= Trissoplax dentata ( Stimpson, 1858) ]

Eucrate costata Yang & Sun, 1979 [= Trissoplax dentata ( Stimpson, 1858) ]

Eucrate haswelli Campbell, 1969 [= Trissoplax dentata ( Stimpson, 1858) ]

Key to species of Eucrate

1. Third (excluding outer orbital tooth) anterolateral tooth absent (only slight elevation may be present), carapace with relatively long posterolateral borders (e.g. Fig. 4 View FIGURE 4 ) ...................................................................................................... 2

– Third (excluding outer orbital tooth) anterolateral tooth present, even if short, sometimes barely noticeable in large individuals, carapace without relatively long posterolateral borders (e.g. Fig. 12 View FIGURE 12 )...................................................... 5

2. Conspicuous frontal notch present; large purple-pink spots on anterior two thirds of dorsal surface of carapace ( Campbell 1969: fig. 1B) .......................................................................................................................... E. sexdentata

– Frontal notch absent or barely noticeable; variously shaped red-brown spots, dots or many small dots on anterior half of dorsal surface of carapace......................................................................................................................................... 3

3. Anterior half or most of carapace and chelipeds with small red-brown dots ( Fig. 2E View FIGURE 2 ), larger dots in small individuals ( Fig. 2F View FIGURE 2 ) .................................................................................................................................................. E. formosensis

– Median portion of carapace with large, irregular dark red-brown spots; small red-brown spots on anterior third of carapace and chelipeds ( Fig. 2C, D View FIGURE 2 ) ............................................................................................................................ 4

4. Median portion of carapace with one large, rounded spot in centre, typically flanked on each side and anteriorly by smaller spots ( Fig. 2C View FIGURE 2 ); western Pacific in distribution ................................................................................. E. alcocki Median portion of carapace with two large, irregular, red-brown spots in centre, typically flanked by two smaller, vertically placed spots ( Fig. 2D View FIGURE 2 ); Indian Ocean in distribution ............................................................. E. indica n. sp.

5. P5 propodus noticeably short, wide ( Figs. 12 View FIGURE 12 , 13C View FIGURE 13 ; Campbell 1969: fig. 4G); three anterolateral teeth short, second and third nearly equal ( Fig. 13B–D View FIGURE 13 ) ......................................................................................................... E. tripunctata

– P5 propodus slender, not wide; three anterolateral teeth of varying size, first much smaller than second................... 6

6. First anterolateral tooth very short, nearly disappearing in large individuals ( Fig. 6A–C View FIGURE 6 ; Campbell 1969: fig. 6B, K); typically one large spot on central region of carapace ( Figs. 5A, B, D View FIGURE 5 ; 6A View FIGURE 6 ) ................................................ E. dorsalis

– First anterolateral tooth well developed, not noticeably reduced in size; carapace with reticulated pattern of spots or two spots on anterior half ............................................................................................................................................. 7

7. Ventral surface of cheliped meri with conspicuous, high tubercles; intricate, reticulated pattern of dots, spots across carapace, chelipeds, ambulatory legs ( Fig. 7C–F View FIGURE 7 ) (preserved specimens with two triangular or hexagonal patterns on mesogastric region) ......................................................................................................................................... E. solaris

– Ventral surface of cheliped meri smooth or with short granules; small dots on anterior third of carapace and on chelipeds plus two small, oval, red-brown spots may be present on branchial region of carapace at some distance from each other ( Fig. 2A View FIGURE 2 ) ........................................................................................................................................ E. crenata