Trissoplax dentata ( Stimpson, 1858 ) CASTRO, PETER & NG, PETER K. L., 2010

CASTRO, PETER & NG, PETER K. L., 2010, Revision of the family Euryplacidae Stimpson, 1871 (Crustacea: Decapoda: Brachyura: Goneplacoidea), Zootaxa 2375 (1), pp. 1-130 : 98-104

Trissoplax dentata ( Stimpson, 1858) , new combination

( Figs. 39D–F ; 40A–F ; 41A–G ; 43A–C )

Heteroplax dentata Stimpson, 1858: 94 (40); 1907: 94 [ China]. — Balss 1922a: 137 [in list]. — Guinot 1969b: 511 [in list]. — Dai et al. 1986: 371, fig. 194 [ China]. — Dai & Yang 1991: 400, fig. 194 [ China]. — Naiyanetr 1998: 78;

2007: 90 [Andaman Sea coast of Thailand]. — Ng et al. 2008: 78, 79 [in list]. — Yang et al. 2008: 770 [in list]

[ China]. — Clark et al. 2008: 52 [western Thailand]. Eucrate affinis Haswell, 1882a: 547 ; 1882b: 86 [ Australia]. — Stebbing 1920a: 238; 1921b: p. 458, pl. 15 (110) [ South

Africa]. — Campbell 1969: 118 [in key], 122, figs. 2, 3 [ Australia]. — Guinot 1971: 1080 [in list]. — Springthorpe

& Lowry 1994: 92 [type material]. — Davie 2002: 198 [fig.], 199. — Thoma 2007: 299 [Western Australia.] —

Hutchins & Gomez 2007: 331 [in list] [Western Australia]. — Ng et al. 2008: 78 [in list]. Pseudorhombila sulcatifrons var. australiensis Miers, 1884: 242 , pl. 24, fig. C, c [ Australia]. (?) Eucrate affinis — De Man 1887: 89, pl. 5, figs. 5–7 [ Myanmar = Burma]. Heteroplax dentatus — Walker 1887: 110 [in list] [ Singapore]. (?) Eucrate crenata var. affinis — Alcock 1900: 299 [in key], 300. Eucrate crenata var. dentata — Nobili 1906b: 297 [Gulf of Aden]. Eucrate crenata dentata — Chhapgar 1957: 437, pl. 11, fig. j-l. [west coast of India]. not Eucrate crenata var. dentata — Alcock 1900: 299 [in key], 301 [ India, Hong Kong]. — Sankarankutty 1966: 350 [in list] [ India] (? = Eucrate alcocki Serène , in Serène & Lohavanijaya, 1973; E. indica n. sp.) not Heteroplax dentata — Rathbun 1910: 342 [Gulf of Thailand]. [not Trissoplax dentata ( Stimpson, 1858) ] Eucrate dentata — Tesch 1918: 158 [in key, footnote]. — Campbell 1969: 119 [in key], 132 [discussion]. Eucrate sulcatifrons — Stephensen 1946: 167, fig. 45 A, B [Persian Gulf]. not Eucrate sulcatifrons — Barnard 1950: 282 [in key], 295, fig. 54 d, e. [not Eucrate sulcatifrons Stimpson, 1858 =

Eucrate crenata (De Haan, 1835) ] Eucrate haswelli Campbell 1969: 119 [in key], 130, figs. 2, 5 [ Australia]. — Guinot 1971: 1080 [in list]. — Tirmizi &

Ghani 1988: 139, figs. 2, 3; 1996: 77 [in key], 77, figs. 29, 30 [ Pakistan]. — Springthorpe & Lowry 1994: 101 [type material]. — Davie 2002: 199 [in list]. — Apel 2001: 102 [Persian Gulf]. — Ng et al. 2008: 78 [in list]. — Naderloo

& Sari 2007: 344, 347 [Persian Gulf]. — Yang et al. 2008: 770 [in list] [ China]. not “? Heteroplax dentatus ” — Serène & Lohavanijaya 1973: 73, 98, figs. 178–182, pl. 17, figs. A-D [ Philippines]. [not

Trissoplax dentata ( Stimpson, 1858) = Heteroplax tuberosa n. sp] Heteroplax transversus — Serène & Lohavanijaya 1973: 72 [in key], 73, 98, figs. 183, 184, pl. 18, fig. A [Gulf of Thailand]. Eucrate costata Yang & Sun 1979: 4 , 10, fig. 3, plate, figs. 5, 6, 9 [ China]. — Dai & Yang 1991: 401 [in key], 404, fig.

197(1), pl. 54, fig. 5 [ China]. — Ng et al. 2008: 78 [in list]. — Yang et al. 2008: 770 [in list] [ China].

Type material of Heteroplax dentata Stimpson 1858 , lost.

Type locality. “among the islands on the coast of China near Hong Kong ”, “shelly bottoms, in 10–15 fathoms” (18–27 m).

Neotype (see Remarks below): male, 16.4 mm × 21.5 mm ( QM W27400) ( Figs. 40A ; 41 ); type locality. Hong Kong, New Territories , Tolo Harbour, stn. 64, 22°45’N, 114°20’E.

Type material of Eucrate affinis Haswell, 1882 , dry male lectotype, 6.6 mm × 8.7 mm, 1 dry female paralectotype ( AM P2972 ) ( Fig. 40D ), designated by B. M. Campbell; type locality: Australia, Port Denison , off Holborn I., 36 m (see Springthorpe & Lowry 1994: 92) .

Type material of Pseudorhombila sulcatifrons var. australiensis Miers, 1884 , pre-adult female holotype, 8.4 mm × 6.0 mm ( NHM 1882.93 ) ( Fig. 40F ); type locality: Australia, Port Molle , 26 m, HMS Alert .

Type material of Eucrate haswelli Campbell, 1969 , male holotype, 15.0 mm × 19.5 mm ( AM P6991 ) ( Fig. 40B ); type locality: Australia, Queensland, Port Denison , intertidal (see Springthorpe & Lowry 1994: 101) .

Type material of Eucrate costata Yang & Sun 1979 , male holotype ( BMNH J79149 ), 1 male paratype, 25.0 mm × 19.0 mm ( BMNH J79140 ) ( Fig. 40E ); type locality: China, Fujian Province, Dongshan .

Material examined. Gulf of Aden. Djibouti, F. P. Jousseaume coll., 1897, id. as “ Eucrate crenata var. dentata Stm ” by G. Nobili, 1905: 2 females ( MNHN-B12514 ) .

Persian Gulf. Det. as E. aff. haswelli by M. Apel, 2 males, cl 6.5 [rest of carapace damaged], 8.1 mm × 11.4 mm, 2 females 6.5 mm × 9.2 mm, 6.7 mm × 9.3 mm, 1 ovigerous female, 7.7 mm × 10.6 mm (MNHN- B12513).

Pakistan. Korangi Creek , south of Karachi, N.M. Tirmizi leg., 15.03.1992: 2 males, 15.0 mm × 19.5 mm, 15.5 mm × 20.9 mm, 1 female, 14.9 mm × 19.9 mm ( RMNH D46768) .

(?) India. Leg. Marine Research Station , Ratnagiri, jetty Mirya: 1 female [incomplete], 17.9 mm × 23.0 mm ( MNHN-B10559 ) .

Thailand. Andaman Sea coast, Ranong, stn. 126, offshore, TILS project, P. Clark coll., 29.11.2007: 1 male, 6.2 mm × 8.3 mm ( NHM) .

China. Amoy, 07.1932, leg. National Wu-Han University, no. 80: 1 female, 16.1 mm × 20.6 mm (MNHN- B10149) .

Hong Kong. Unknown locations, T49, sp. 38, 1992: 1 ovigerous female, 14.8 mm × 19.0 mm ( SWIMS CRU-P12-015 ) ; T4/2, sp. 46: 1 female, 13.7 mm × 18.4 mm ( SWIMS) ; T10 , sp. 60: 3 males, 1 female ( SWIMS CRU-92-011 ) ; 1 male ( SWIMS CRU-92-049 ) . – New Territories , Tolo Harbour, 22°45’N, 114°20’E, stn. 64, P. Davie coll.: male neotype (here designated), 16.4 mm × 21.5 mm ( QM W27400) . – GO 788, 5A: 1 male, 3.1 mm × 4.1 mm, 1 male, 3.8 mm × 4.9 mm ( QM W28382) .

Thailand. Gulf of Thailand, off Pattaya, L. B. Holthuis & P. K. L. Ng coll., 25.12.1991: 2 males, 4.6 mm × 6.4 mm, 6.9 mm × 9.6 mm ( ZRC 1992.10297 – 10298 ) .

Gulf of Thailand, stn. GVF 53, channel between Songkhla and Ko Nu I., 07°14’N, 100°36’E, 03.11.1957: 1 ovigerous female, 7.3 mm × 9.1 mm (ex USNM access no. 230087, MNHN-B24502 ) .

Singapore. Southern islands , 1992: 1 male, 15.2 mm × 19.4 mm ( ZRC 1992.7922 ) .

Tuas Basin, P. K. L. Ng et al. coll., 15.01.1994: 1 pre-adult male, 3.5 mm × 4.9 mm, 2 males, 5.6 mm × 7.3 mm, 6.5 mm × 8.8 mm, 1 pre-adult female, 5.7 mm × 7.5 mm, 3 females, 5.9 mm × 8.3 mm, 6.5 mm × 8.4 mm, 8.7 mm × 11.5 mm ( ZRC 2000.2240).

Off Changi, dredging, P. K. L. Ng coll., 17.12.1998: 1 female, 7.7 mm × 10.6 mm ( ZRC 1998.1231 ). – Changi Beach, beach seine, P. K. L. Ng coll., 02.04.2003: 1 male, 6.9 mm × 9.1 mm ( ZRC 2004.0758 ) .

SAF jetty, Changi Point, washed dead on shore, Chan S. Y. coll., 11.03.2005: 2 males, 20.0 mm × 26.2 mm, 21.5 mm × 28.9 mm ( ZRC 2008.1236).

Semekau, H. H. Tan coll., 18.02.2009: 1 female ( ZRC 2009.0048 ) .

Unknown location, J. C. Y. Lai coll., 15.09.07: 1 male, 14.1 mm × 18.4 mm ( ZRC 2009.0375 ) .

Indonesia. Kai Is. Danish Kai Expedition, stn. 116, 05°57'' S, 136°34''E, 22 m, 07.08.1922, id. as Heteroplax dentata by T. Odhner, 1924: 1 female ( ZMUC CRU-1519 ) .

Australia. Queensland, Port Denison , intertidal: male holotype of Eucrate haswelli Campbell, 1969 , 15.0 mm × 19.5 mm ( AM P6991 ) .

Queensland, Port Molle, HMS Alert , 26 m, 1882: pre-adult female holotype of Pseudorhombila sulcatifrons var. australiensis Miers, 1884 , 8.4 mm × 6 mm ( NHM 1882.93 ) .

“Eastern Seas”. Identified as “ Pilumnoplax sulcatifrons ”: 2 males, 9.4 mm × 7.5 mm, 8.9 mm × 6.8 mm (NHM 1847.21).

Unknown location. Loc. 0047, stn. 003-5, 17.02.1983: 2 males, 3 pre-adult females, 3 females ( LACM) .

Diagnosis. Suborbital border with triangular inner suborbital tooth, short median lobe ( Fig. 41A, B ). Conspicuous tomentum on chelipeds ( Fig. 39D–F ; 40A–C, E ; 41E ). Smooth chelipeds, without tubercles ( Fig. 41E ).

Remarks. The status of H. dentata , one of the two species of Heteroplax sensu lato described by Stimpson (1858) from Hong Kong, had remained problematic until now. The clarification of Stimpson’s (1858) description (see Remarks for Trissoplax n. gen.) and the designation of a neotype (see below) now permits settling the status of several other species that were described by other authors who were not aware of the real identity of Stimpson’s H. dentata , or even the case where a new species was not recognized because both of Stimpson’s species were confused with each other. Nevertheless, authors such as Walker (1887), Nobili (1906), and T. Odhner (see Material examined above) correctly identified their material as belonging to Stimpson’s species.

A series of seven specimens from Singapore ( ZRC 2000.2240 ) ranging from a pre-adult male (3.5 mm × 4.9 mm) to an adult female (8.7 mm × 11.5 mm), plus additional specimens of various sizes from other locations, drew light on the ontogeny of the diagnostic characters of T. dentata . The smallest pre-adult male barely shows a third anterolateral tooth, only a short tubercle, and, as in the remaining small individuals, does not show the characteristic tomentum on the distal margin of the cheliped carpi, only many short plumose setae that increase in number with carapace size. The short tufts of setae of two pre-adult Hong Kong specimens (3.1 mm × 4.1 mm, 3.8 mm × 4.9 mm; QM W28382) do indeed correspond to Stimpson’s “tuft of pubescence”. Another character, the shape of the anterolateral borders of the carapace, changes from being almost parallel to each other in small individuals ( Fig. 39D–F ) to arched in the largest ones ( Fig. 40A–E ) .

The carapace and single cheliped of two pre-adult males (3.1 mm × 4.1 mm, 3.8 mm × 4.9 mm; QM W28382) from Hong Kong also agree with Stimpson’s (1858) description of H. dentata . The smallest specimen, however, lacks the third anterolateral tooth, which was described ( Stimpson 1907: 94) as “inconspicuous, formed only by a slight emargination”. The only available cheliped has a short tuft of setae on the distal margin of the carpus.

The many specimens examined agree with the characters given in Stimpson’s description of his Hong Kong specimens. An exception is the presence of a median notch in the front. It was indicated as absent in Stimpson’s material ( Stimpson 1907: 94) but this character may have been missed as the notch is small and may be obscured by sediment.

Eucrate affinis Haswell, 1882 , described from Queensland, Australia ( Haswell, 1882a: 547; 1882b: 86), was among the species of Eucrate revised by Campbell (1969: 118, 122, fig. 3). Campbell’s illustrations of Haswell’s type material (male lectotype and a female paralectotype (AM P2972) selected as such by Campbell from two syntypes) show strong similarities to T. dentata in the general shape of their carapaces and, most especially, orbits and eye peduncles that are much longer than those of Eucrate . Campbell unfortunately did not discuss Haswell’s species in detail and concluded that the most “characteristic feature of this species is probably the presence of the short strong ridges at the bases of the third and fourth anterolateral teeth”, a feature that is shown in his figures ( Campbell 1969: fig. 3b, H) but without mentioning the long orbits and eye peduncles, which are also shown in his figures. Haswell’s species is only known from the relatively small male lectotype and female paralectotype (AM P2972) as selected by Campbell. Their carapace widths were measured by Campbell as 8.7 mm and 12.4 mm, respectively. Both specimens are dry and fragile but photographs (one of which is reproduced as Fig. 40D ) confirm that Haswell’s specimens belong to T. dentata ( Stimpson, 1858) . Campbell, however, provided a drawing of the abdomen of the male lectotype ( Campbell 1969: fig. 3F), which shows a telson that is slightly shorter than that of T. dentata . The specimen drawn by Campbell was a small male so it is possible that the telson was not fully developed. It is also possible that the abdomen was not fully extended and straight when drawn. Not mentioned by Stimpson in his description of H. dentata , but observed by Campbell in Haswell’s holotype, and by us in specimens of T. dentata is a slight, granular elevation on the branchial region parallel to each posterolateral margin. These are indicated in Campbell’s figure of E. affinis ( Campbell 1969: fig. 3B, H) but they are not as evident in larger individuals such as the male holotype of E. haswelli (15.0 mm × 19.5 mm, AM P6691; Fig. 40B ), another junior synonym of T. dentata (see below), or in the neotype of T. dentata (16.4 mm × 21.5 mm, QM W27400; Fig. 40A ).

Campbell (1969: 119) regarded Stimpson’s H. dentata as a species of Eucrate and included it in his key to species. He discussed in detail Stimpson’s description ( Campbell 1969: 132) and pointed out six similarities and three differences between it and his new species E. haswelli . One difference was in the carapace length to width ratio, 1.34 in the male holotype of E. haswelli against 1.46 in Stimpson’s specimen. As pointed out in the case of Stimpson’s H. transversa (see Remarks above), the difference may be due to the possibility that Stimpson’s specimen, whose sex was not indicated, being a female. A second difference resulted after erroneously concluding from Stimpson’s description that the second anterolateral tooth (first tooth below the outer orbital tooth) was “almost obsolete” in H. transversa . He finally presumed (“by inference”) that a median frontal notch was absent in H. transversa because its presence was not mentioned by Stimpson. A colour photograph of the male holotype of E. haswelli Campbell, 1969 (15.0 mm × 19.5 mm, AM P6691; Fig. 40B ) confirms that Campbell’s species is indeed a junior synonym of T. dentata ( Stimpson, 1858) .

Other authors referred specimens collected elsewhere to Eucrate affinis Haswell, 1882 . Such is the case of four specimens from the Mergui Archipelago, Andaman Sea identified “with some hesitation” as E. affinis by De Man (1887: 89, pl. 5, figs. 5–7), as well as the single specimen of the same collection identified by Alcock (1900: 300) as E. crenata var. affinis . Campbell (1969: 128) referred to E. tripunctata Campbell, 1969 , the four specimens identified “with some hesitation” as E. affinis by De Man (1887: 89, pl. 5, figs. 5–7), as well as the single specimen of the same collection identified by Alcock (1900: 300) as E. crenata var. affinis . Campbell’s decision was made on account of the restriction of the cheliped tomentum to “the upper border of the wrist of the cheliped”, the proportions of the P5 propodus, and the similarity between the outer orbital teeth and the first two anterolateral teeth. Based solely on De Man’s description and his figures, however, it is clear that the specimens do not belong to E. tripunctata . The anterolateral teeth, described by De Man (1887: 90, pl. 5, fig. 5) as “rather acute”, do not resemble the conspicuously short teeth of E. tripunctata , a feature that is observed even in pre-adults ( Campbell 1969: fig. 4K, L). Furthermore, the male telson ( De Man 1887: pl. 5, fig. 6) is shorter than that in E. tripunctata . Alcock’s specimen was described as being “more sculptured” than that of E. crenata , which is in sharp contrast to the smoother carapace of E. tripunctata .

The similarities between De Man’s material and T. dentata are evident from his figures, most especially the long orbits and eye peduncles but there are some differences. Assuming that the figures are accurate, the anterolateral teeth are subequal, the orbits are slightly transverse, and the P5 dactylus relatively shorter than in T. dentata . The identity of the material, as well as Alcock’s E. crenata var. affinis thus remains unknown.

Also referred to E. affinis were specimens from South Africa ( Stebbing 1920a: 238; 1921b: p. 458, pl. 15). Stebbing’s illustration of the carapace shows the elongated orbits and eye peduncles and what appear to be a granular elevation parallel to the left posterolateral margin. Nevertheless, the tomentum on the cheliped carpi is not illustrated, the P5 propodus is proportionally short and wide, the anterolateral teeth show acute tips, and the male telson is shorter than in T. dentata . Stebbing’s material from South Africa is referred to as Eucrate sulcatifrons Stimpson, 1858 , a junior synonym of E. crenata (De Haan, 1835) , by Barnard (1950: 295, fig. 54d, e), who mentions that the “distal end of wrist [is] more or less covered with thick fur”. His figure shows orbits and eye peduncles that are longer than in Eucrate and the relatively large outer orbital and anterolateral teeth characteristic of T. dentata .

Often placed in synonymy with Haswell’s Eucrate affinis (e.g. Campbell 1969: 122), Pseudorhombila sulcatifrons var. australiensis Miers, 1884 ( Miers 1884: 242, pl. 24, fig. C, c) agrees with some of the diagnostic characters of T. dentata as defined here. Miers compared his female specimen from Queensland, Australia with Stimpson’s H. dentata and stated that his variety differs “it would appear, [by] the shorter thicker eye-peduncles”, which is not readily apparent from Miers’ figure, and a first anterolateral tooth that is “as long as the preceeding [sic]” (the outer orbital tooth). Campbell (1969: 126) examined photographs of the dry holotype (deposited at NHM) and found that there are some errors in Miers’ representation of, among other structures, the anterolateral teeth and the P5. Nevertheless, absent from Miers’ specimen is the tomentum on the cheliped carpi, although short setae instead of a conspicuous tomentum has been observed in small specimens of T. dentata like that of Miers’, which was only 6 mm × 8 mm ( Miers 1884: 242). Examination of the pre-adult female holotype of Pseudorhombila sulcatifrons var. australiensis Miers, 1884 (8.4 mm x 6.0 mm, NHM 1882.93; Fig. 40F ) confirms it is a junior synonym of T. dentata ( Stimpson, 1858) .

The photographs of a Gulf of Thailand specimen identified as “ Heteroplax transversus ” by Serène & Lohavanijaya (1973: figs. 183, 184, pl. 18, fig. A) is clearly identifiable as T. dentata . The specimen identified as “? Heteroplax dentatus ” ( Serène & Lohavanijaya (1973: 73, 98, figs. 178-182, pl. 17), however, belongs to Trissoplax tuberosa n. sp. (see below). The authors were, like many others, obviously confused by Stimpson’s ((1858, 1907) descriptions of the two species.

Eucrate costata Yang & Sun, 1979 , described from southern China can also be referred to T. dentata . This synonymy is clearly apparent in the photographs of the carapace (broad carapace, characteristic shape of the anterolateral teeth) and long orbits and eye peduncles ( Yang & Sun 1979: plate, figs. 5, 6, 9), particularly since the photographs are side by side to photographs of two species of Eucrate . Also characteristic of T. dentata is the elongated male telson and the proportionally slender P5 propodus and dactylus ( Yang & Sun 1979: figs. 3, 4). The species was described as resembling more Eucrate haswelli and E. affinis but a table contrasting the three species ( Yang & Sun 1979: 11) listed five characters, three of which involved the sculpturing of the carapace and cheliped, and two slight differences in the morphometry of the P5 propodus and male abdomen. The authors did not mention their examination of material of the two “ Eucrate ” species so their data was taken from Campbell’s rather incomplete illustrations. As mentioned above, there is a slight difference in the shape of the male telson of E. affinis as figured by Campbell (1969: fig. 3F) and the more slender telson of E. costata shown by Yang & Sun and the specimens of T. dentata examined here. Photographs of the male paratype of E. costata (19.0 mm × 25.0 mm, BMNH J79140 ; Fig. 40E ) confirm the synonymy.

In view of the complex and confusing taxonomic history of the species and in the interest of long-term nomenclatural stability, we hereby designate a male (16.4 mm × 21.5 mm; QM W27400) from Hong Kong, the type locality of Stimpson’s species, as the neotype of Heteroplax dentata Stimpson, 1858 . This action effectively makes Eucrate affinis Haswell, 1882 , E. costata Yang & Sun, 1979 , E. haswelli Campbell, 1969 , and Pseudorhombila sulcatifrons var. australiensis Miers, 1884 , junior subjective synonyms of Heteroplax dentata Stimpson, 1858 .

The specimen figured by Dai et al. (1986: fig. 194) and Dai & Yang (1991: fig. 194) of a specimen from Guandong, southern China conforms to T. dentata . It shows three anterolateral teeth in addition of an obtuse but conspicuous outer anterolateral tooth, and a smooth chelipeds propodus.

The “ Eucrate crenata var. dentata ” records of Alcock (1900) (see Remarks for E. alcocki ) probably refer to either E. alcocki Serène , in Serène & Lohavanijaya, 1973, or E. indica n. sp. The record of “ Eucrate crenata dentata ” by Chhapgar (1957: 39, pl. 11, figs. j, k, l), however, is clearly T. dentata as presently defined here as his figures leave no doubt about its identity. Material from the Iranian Gulf identified by Stephensen (1946: 167, fig. 45) as Eucrate sulcatifrons , a junior synonym of E. crenata De Haan, 1835 , was examined by Apel (2001: 102) and according to him, is actually E. haswelli ; which is here regarded as a junior synonym of T. dentata .

The specimen photographed by Serène & Lohavanijaya (1973: pl. 17, fig. C) does show four teeth (in addition of acuminate outer orbital tooth) but their specimen does not conform to Stimpson’s description. The chelipeds propodus of their specimen has conspicuous tubercles whereas Stimpson (1907) described the chelipeds as “smooth, and glossy”.

Two pre-adult specimens from the Gulf of Thailand (1.8 mm × 1.8 mm, 2.6 mm × 3.0 mm; USNM 39740), which belong to a batch of four females and one male recorded by Rathbun (1910: 342), do not belong to H. dentata . Their small size makes a conclusive identification impossible but they have clear affinities to Carcinoplax and Psopheticus Wood-Mason, 1892 , both included in the Goneplacidae sensu stricto.

Differences between T. dentata and its only known congener are given in the description of T. tuberosa n. sp. (see below).

Colour pattern. There is considerable variation in the colour pattern of T. dentata . Stimpson’s Hong Kong live specimens were described as having a gray or brown carapace, “whitish posteriorly, and with a transverse narrow white band being the eyes … frontal region and feet punctuate with red” (Stimpson 1905: 95). Pakistan specimens were described by Tirmizi & Ghani (1996: 80, as Eucrate haswelli ) as “pale with purple dots, chelipeds white with purple dots”. Two preserved male specimens from Singapore (14.1 mm × 18.4 mm, ZRC 2009.0375; 15.2 mm × 19.4 mm, ZRC 1992.7922) showed small dots on the dorsal surface of the chelipeds and the anterior third of the carapace. The same colour pattern is observed in a photograph of a fresh specimen from the Persian Gulf provided by R. Naderloo (Forschunginstitut Senckenberg, Frankfurt). A recently preserved, small male (6.2 mm × 8.3 mm; NHM) from the Andaman Sea coast of Thailand showed a broad purplish band across the carapace just below the orbits. The front and the posterior half of the carapace were pinkish ( Fig. 39D ). Small specimens photographed live in Singapore, however, show light-coloured carapaces with an irregular pattern of dots, some of which take the form of two spots on the dorsal surface ( Fig. 39E, F ).

The Indian specimen illustrated by Chhapgar (1957: pl. 11, fig. j, as Eucrate crenata var. dentata ) shows two small, round spots on the carapace, but specimens were described as “bright yellow, with minute red spots scattered throughout. One of the specimens has two black square patches on the outer sides of the gastric region”. A similar colour in life colour pattern has also been observed among some specimens, including some preserved ones from an unknown location (LACM).

Distribution. Wide Indo-West Pacific distribution: South Africa ( Stebbing 1920a), Gulf of Aden, Persian Gulf, Pakistan, India ( Chhapgar 1957), Thailand (Andaman Sea and Gulf of Thailand coasts), China (including Hong Kong), Singapore, Australia (Queensland). Depth: shallow subtidal to 40 m.

Figures

FIGURE 39. Colours in life. A, Euryplax nitida Stimpson, 1871; male neotype (7.1 mm × 11.3 mm) (UF 15166), Gulf of Mexico; B, Euryplax nitida Stimpson, 1871; male (4.4 mm × 7.0 mm) (UF 15168), Gulf of Mexico; C, Psopheticoides sanguineus Sakai, 1969, male (22.2 mm × 26.7 mm) (MNHN-B29728), Philippines, Bohol, Panglao; D, Trissoplax dentata (Stimpson, 1858), male (6.2 mm × 8.3 mm) (NHM), Thailand, Andaman Sea; E, Trissoplax dentata (Stimpson, 1858), young male, not preserved, Singapore, Changi; F, Trissoplax dentata (Stimpson, 1858), female (8.7 mm × 11.5 mm) (ZRC 2000.2240), Singapore. Photo credits: A, B by Florida Museum of Natural History (UF); D by P. F. Clark (NHM).

FIGURE 40. Trissoplax dentata (Stimpson, 1858); A, male neotype of Heteroplax dentatus Stimpson, 1858 (16.4 mm × 21.5 mm) (QM W27400), Hong Kong, Tolo Harbour; B, male holotype of Eucrate haswelli Campbell, 1969 (15.0 mm × 19.5 mm) (AM P6991), Australia, Queensland, Port Denison; C, male (20.0 mm × 26.2 mm) (ZRC 2008.1236), Singapore, Changi Point; D, male lectotype of Eucrate affinis Haswell, 1882 (6.6 mm × 8.7 mm) (AM P2972), Australia, Queensland, Port Denison; E, male paratype of Eucrate costata Yang & Sun, 1979 (25.0 mm × 19.0 mm) (BMNH J79140), China, Dongshan, Fujian Province; F, pre-adult female holotype of Pseudorhombila sulcatifrons var. australiensis Miers, 1884 (8.4 mm × 6.0 mm) (NHM 1882.93), Australia, Queensland, Port Molle. A–C, E, F, overall views; D, dorsal view of carapace. Photo credits: D by R.T. Springthorpe © (AM), F by P. Crabb (NHM).

FIGURE 41. Trissoplax dentata (Stimpson, 1858); A–D, F, male neotype of Heteroplax dentatus Stimpson, 1858 (16.4 mm × 21.5 mm) (QM W27400), Hong Kong, Tolo Harbour; E, male (20.0 mm × 26.2 mm), Singapore, Changi Point; G, female (8.7 mm × 11.5 mm) (ZRC 2000.2240) (ZRC 2008.1236), Singapore. A, frontal view showing third maxillipeds; B, frontal view showing orbits and antennae; C, anterior portion of male thoracic sternum; D, posterior portion of male thoracic sternum and abdomen; E, outer surface of right chela; F, male sterno-abdominal cavity, G1 and penis; G, female thoracic sternum and vulvae. Abbreviations: a1–a3 = male abdominal somites 1, 2, 3, respectively; cx5 = coxa of fifth pereopod (P5); es7 = episternite 7; G1 = first male pleopod; G2 = second male pleopod; mg = median groove; p = penis; s4–s7 = thoracic sternites 4 to 7, respectively; vc = sternal vulvar cover.

FIGURE 43. Gonopods. A–C, Trissoplax dentata (Stimpson, 1859); male neotype of Heteroplax dentata Stimpson, 1859 (16.4 mm × 21.5 mm) (QM W27400); D–F, Trissoplax tuberosa n. sp., male holotype (7.6 mm × 10.2 mm) (MNHN-B10340), Indonesia, Moluccas. A, B, D, E, right G1, dorsal view; C, F, right G2, dorsal view. Scale bars: A, 1.0 mm; B, D, 0.5 mm; C, E, F, 0.2 mm.