Doclea canalifera Stimpson, 1857

Chen, H. - L. & Ng, Peter K. L., 2004, On Two Species Of Spider Crabs Of The Genus Doclea (Crustacea: Decapoda: Brachyura: Majidae: Pisinae) From China, One Of Which Is New, Raffles Bulletin of Zoology 52 (1), pp. 201-208 : 202-207

Doclea canalifera Stimpson, 1857

( Figs. 3 , 4A )

Doclea japonica Ortmann, 1893: 46 , pl. 3 fig. 4; Wagner, 1986: 902; Griffin & Tranter, 1986: 115; Ng et al., 2001: 13.

Doclea canalifera Stimpson, 1857: 217 ; 1907: 7, Pl. 1 fig. 4; Rathbun, 1902: 29; Gee, 1925: 166; Gordon, 1931: 529; Shen, 1940: 80; Griffin, 1974: 10; Dai et al., 1986: 133, pl. 17(7), text fig. 75(2); Dai & Yang, 1991: 148, pl. 148, pl. 17(7), text fig. 75(2).

Doclea ovis – Adams & White, 1848: 7; Wagner, 1986: 897 (part) (not Cancer ovis Fabricius, 1787 ); Dai et al., 1986: 133, pl. 17(6), text fig. 75(1); Dai & Yang, 1991: 148, pl. 147, pl. 17(6), text fig. 75(1).

(for rest of synonymy, see Wagner, 1986: 902, and Ng et al., 2001:

13, under D. japonica )

Material examined. – China: 1 male (cw 56.1 mm, cws 58.4 mm, cl 52.8 mm, cls 60.3 mm) ( ZRC 1999.447 ), neotype of Doclea canalifera Stimpson, 1857 , Qianjiang Fish Port, Guangdong, Nanao Island, 150 km northeast of Hong Kong , China, coll. Y. Cai & N. K. Ng, 12 Nov.1998 ; 1 male, 2 females ( ZRC) , 1 juvenile female ( ZRC 1999.462 ), Qianjiang Fish Port, Guangdong, Nanao Island, 150 km northeast of Hong Kong , China, coll. Y. Cai & N. K. Ng, 12 Nov.1998 ; 1 female ( IOCAS), Fujian Province, China , coll. 15 Apr.1957 ; 5 males (4 juveniles), Tung-Shan , Fujian Province, China, coll. 16 Apr.1957 ; 1 male ( IOCAS), Sing-Chun, Hainan, China , coll. 21 Apr.1955 ; 1 male, 1 female ( IOCAS), Sang-Ya, Hainan, China , coll. 14 Apr.1955 ; 1 male ( IOCAS), Sang-Ya, Hainan, coll. 25 Dec.1934 ; 1 male (cw 30.2 mm, cws 34.9 mm, cl 30.8 mm, cls 40.9 mm) ( IOCAS S61-39 ), station 6026, 26.5m, South China Sea , 6 Apr.1959 ; 1 male ( ZRC), station 6185, N36B15, 55 m, South China Sea , coll. Tang, 18 Apr.1959 ; 4 small males ( IOCAS S61-39 ), station 6026, 26.5m, South China Sea , 6 Apr.1959 ; 1 male ( IOCAS 119 B-126), station 6004, 37.4 m, South China Sea , 11 Nov.1959 ; 1 juvenile female ( IOCAS SIII36 B-8), station 6009, South China Sea , rough sand, 24 m, coll. 21 Jul.1959 ; 1 male ( IOCAS), station 6192, 21˚00’N 109˚15’E, northern South China Sea , 16 m, coll. 17 Jul.1960 ; 5 males ( IOCAS), station 7104, 20˚15’N 109˚45’E, Beibu Bay, northern South China Sea , 29 m, coll. 26 Aug.1962 ; 1 juvenile female ( IOCAS X177 B-61), station 7202, 31 m, rough sandy bottom, Beibu Bay , 22 Jan.1962 ; 1 male, 1 female ( IOCAS), Shan-Wei, Guangdong, China , coll. 10 Feb.1955 ; 1 male (cw 36.0 mm, cws 43.9 mm, cl 37.6 mm, cls 49.8 mm) ( USNM 59168 ), Chekiang (= Zhejiang) Province, Hangzhou, 18 Jul.1923 , exchange with National Southeastern University . Taiwan: 1 male ( ZRC 1998.436 ) , 1 female ( ZRC 1998.445 ), Tashi, Ilan County, northeastern Taiwan , coll. P. K. L. Ng, 17 Jul.1994 ; 1 female ( ZRC 1998.445 ), Tashi, Ilan County, northeastern Taiwan , coll. X. Q. Ng, 17 Oct.1985 ; 1 male, 1 female ( ZRC 1998.184 ), Tashi, Ilan County, northeastern Taiwan , coll. P. K. L. Ng, 3-4 Aug.1996 ; 1 juvenile male ( ZRC 1999.766 ), Tashi, Ilan County, northeastern Taiwan , coll. P. K. L. Ng & K. Lim, May.1999 ; 1 juvenile female ( ZRC 1999.546 ), Tashi, Ilan County, northeastern Taiwan , coll. 19 November 1997 ; 2 males, 1 juvenile female ( ZRC 1998.185 ), Tashi, Ilan County, northeastern Taiwan , coll. P. K. L. Ng, 3-4 Aug.1996 ; 1 female (cws 41.4 mm, cls 46.7 mm) ( ZRC 1998.840 ), Tashi, Ilan County, northeastern Taiwan , coll. P. K. L. Ng, 25 May.1997 ; 1 female (cw 21.0 mm, cws 24.4 mm, cl 26.9 mm, cls 30.5 mm) ( ZRC 1998.511 ), Nanfangao, Su-Ao, Ilan County, northeastern Taiwan , coll. P. K. L. Ng & S. H. Tan, 14 May.1998 ; 1 male, 1 female ( ZRC 1998.512 ), Tashi, Ilan County, northeastern Taiwan , coll. P. K. L. Ng, 25 May.1998 ; 2 males (larger cws 66.0 mm, cls 64.6 mm), 2 females (larger cws 60.3 mm, cls 66.1 mm), 1 juvenile male, 1 juvenile female ( ZRC 2001.55 ), Tashi, Ilan County, northeastern Taiwan , coll. K. X. Lee, 2000. THAILAND : 1 female ( ZRC 1992.10315 ), off Pattaya, Gulf of Thailand , coll. P. K. L. Ng & L. B. Holthuis, 25 Dec.1991 ; 1 male (cws 55.2 mm, cl 57.6 mm, cls 63.4 mm) ( ZRC 2000.929 ), Si Racha Port, Chonburi Province, Gulf of Thailand , coll. P. K. L. Ng, 22 Feb.2000 .

Description. – Epigastric region with 3 median low, rounded granules arranged close to each other. Medial line of carapace with 7 rounded granules or spines, last 2 most pronounced, produced as spines. Mesogastric region with 3 longitudinally arranged rounded granules. Protogastric region with 4 obliquely arranged rounded granules, outer- and posteriormost one largest. Metagastric region with a large sharp vertical tubercle medially. Urogastric region with 1 prominent, relatively high but not sharp granule. Cardiac region with 1 obliquely posteriorly directed spine. Intestinal region with 1 large posteriorly directed spine. Subhepatic region with 1 rounded granule dorsally, with 1 large subventral tubercle and 1 smaller granule just anterior to this. Branchial region with 7 rounded granules, 2 adjacent to mesogastric region, 2 closely adjoined medially, with 1 granule anterior and 1 granule posterior to them, adjacent to epibranchial spine. Anterolateral margin with 3 tubercles (progressively larger posteriorly), culminating in very large obliquely posteriorly directed epibranchial spine. Basal antennal article with 1 inner spine. Anterolateral angle of buccal frame produced into a low spine. Pterygostomial canal not discernible. Ambulatory legs long, slender, covered with pile; first ambulatory leg not substantially longer than second pair.

Remarks. – The identity of D. canalifera Stimpson, 1857 , is difficult. It was originally described on the basis of a young male measuring about 42 mm in carapace length (intestinal spine inclusive) from about 20 fathoms (36 m) of water off Tamtoo, south of Hong Kong (see also Rathbun, 1902: 29). In his revision of the genus Doclea, Wagner (1986: 901) commented that “As the type material of D. canalifera is lost it is not certain whether the species are juveniles of D. ovis or of D. japonica ” and “It is uncertain whether STIMPSON’s type material from Hong Kong, described as Doclea canalifera , is a young of this species or of D. ovis . The nomenclatural status of D. canalifera may ultimately be established by the selection of a male neotype from Hong Kong ” (p. 903). Nevertheless, he retained D. canalifera under the synonymy of D. ovis , commenting that the only specimens (two females) he has seen from Hong Kong are D. ovis (however, see later). The problem is vexatious. Griffin & Tranter (1986: 115) commented that “… the two are geographically separated, one occurring in the Indian Ocean east to Singapore [ D. ovis ] and one species occurring around Japan and off China [ D. japonica ]. The former species is clearly D. ovis ”. On the other hand, according to Wagner (1986), the distributions of both D. ovis and D. japonica overlap in the northern part of the South China Sea, with Hong Kong within this range.

The two species are indeed very similar, and only adults can effectively be separated. The G1 structure is the most diagnostic. Adult specimens of D. ovis (ca. 50 mm cws and larger) have the distal part of the G1 very slender and elongate, with a small slender lobe basally ( Figs. 5A, C, D ; cf. Wagner, 1986: Fig. 4 ; Griffin & Tranter, 1986: Fig. 34a). Adult D. japonica on the other hand (ca. 50 mm cws and larger), have the distal part of the G1 separated into two finger-like processes subequal in length ( Figs. 3A, B ; cf. Wagner, 1986: 6; Griffin & Tranter, 1986: Figs. 34b, f, g). Smaller specimens of D. ovis (ca. 30-40 mm cws) still have G1s similar in form to the adults but the elongate distal part is less pronounced and there is no trace of the small basal lobe ( Fig. 5B ). Smaller specimens of D. japonica (ca. 25-40 mm cws) have a G1 distal part in which one projection is finger-like and much larger than the other, and appears somewhat subchelate, but the finger-like projection is still relatively stout and not prominently elongate ( Figs. 3 C-M)). In fact, the size-related variation in G1 form led Dai et al. (1986) and Dai & Yang (1991) to recognise two “species” in China, one with a G 1 in which the two distal projections are subequal in length (their “ D. ovis ”) and one with a G 1 in which one projection is much shorter than the other (their “ D. canalifera ”). Both are actually what is presently called D. japonica . In fact, Wagner (1986) had already illustrated this clearly, showing that juveniles have the second type of G1 ( Wagner, 1986: Fig. 5 ) and adults the first condition ( Wagner, 1986: Figs. 6, 7). In general, specimens smaller than 20-25 mm cws are very difficult to distinguish as their G1 structures are very similar. For females, as noted by Wagner (1986) and Grifffin & Tranter (1986), the overall shape of the vulvae are diagnostic, being more swollen and round in D. japonica ( Fig. 4A ) but transversely ovate and more slit-like in D. ovis ( Fig. 4B ). However, this is only valid for adult females (ca. larger than 45-50 mm cws) in which their vulvae are fully formed and the female abdomen prominently domed and covering most of the thoracic sternum. Smaller female specimens (ca. less than 40-45 mm cws) which have more quadrate and flatter abdomens that do not cover most of the sternum do not have the vulvae raised, and as such, cannot be reliably distinguished. The vulva of small D. japonica superficially resembles that of D. ovis (less swollen and rounded) and confusion can thus result. In general, juvenile specimens of both species cannot be reliably identified on the basis of just external morphology. Wagner (1986) lists material of D. ovis from China, Hong Kong, Philippines and Vietnam, but a good part of this was based on female specimens (sizes not stated) and it is possible that at least some may have been misidentified. Certainly, one adult male specimen from China (USNM 59168) identified by Wagner (1986) as D. ovis is here shown to be clearly D. japonica , its G1 structure being diagnostic (cf. Figs. 3A, B ).

All the specimens we have examined show that the two species have discrete distributions and if they overlap, it can only be in the northern part of the South China Sea, although we have no material that actually shows this. In the Indian Ocean all the way to Singapore and the southern part of the South China Sea, only one species is present, D. ovis . From Japan through to southern China and Taiwan, only D. japonica is present. Although we have not examined the types of D. japonica , all the available data indicates there is only one species in Japan and it is the same as that in China (see also Griffin & Tranter, 1986; Wagner, 1986). The Gulf of Thailand has two species; in the northern part (the Pattaya and Chonburi areas), we only have specimens of D. japonica and from the southern part (Pattani area), we only have specimens of D. ovis . Admittedly, our samples from the Gulf of Thailand are rather limited and we have no material from the central part. As such, it seems more likely that if the distributions of the two species overlap, it would be in the Gulf of Thailand and adjacent areas. The two specimens from Hong Kong (type locality of D. canalifera ) referred to D. ovis by Wagner (1986: 898) are both females (NHM 1930.12.2.263, coll. Barney). Paul Clark (NHM) was kind enough to check these specimens for us. Of the two, one is in very poor condition and the carapace is missing. The other specimen is intact and is an ovigerous female measuring 51 mm cws. The vulvae of this specimen matches that for what is presently called D. japonica ( Fig. 4A ) and not D. ovis ( Fig. 4B ) (P. F. Clark, pers. comm.), confirming our suspicion that there are actually no known confirmed records of D. ovis from Chinese waters. The records from Vietnam ( André, 1931; Serène, 1937; Dawydoff, 1952; Wagner, 1986), Gulf of Thailand ( Rathbun, 1910; Suvatti, 1937, 1950; Naiyanetr, 1980, 1998; Wagner, 1986) and Philippines ( Wagner, 1986) will also need to re-examined to see if they belong to D. ovis and/or D. japonica .

As a result, we do not think D. canalifera Stimpson, 1857 , is synonymous with D. ovis ( Fabricius, 1787) , contrary to Wagner’s (1986) supposition. In fact, all the available evidence points to the fact that D. canalifera is actually identical with what is presently called D. japonica . To conclusively resolve the taxonomic impasse over the identity of D. canalifera and the problem of Stimpson’s lost type(s), a neotype is clearly necessary. The only specimens known from Hong Kong (NHM 1930.12.2.263), unfortunately are females, and although one of them is what is presently known as D. japonica , in the context of the present problem, selection of an adult male is clearly preferable. To this effect, we hereby select a recently collected male (cws 58.4 mm, cls 60.3 mm) (ZRC 1999.447) from Nanao Island in Guangdong Province, southern China, as the neotype of Doclea canalifera Stimpson, 1857 . In its external features, it agrees well with the brief description and simple figure of the species by Stimpson (1857, 1907). This locality is only about 140 km northeast of Hong Kong. Doclea japonica Ortmann, 1893 , thus becomes a subjective junior synonym of D. canalifera Stimpson, 1857 . This should not cause any problems as the name D. japonica was only resurrected from the synonymy of D. ovis relatively recently by Wagner (1986) and Griffin & Tranter (1986), and has been used only sporadically. The species has no economic value and has not been used extensively for research.

A note on Doclea ovis ( Fabricius, 1787) is necessary. The species was described (as Cancer ovis ) from “ India orientali” by Fabricius (1787: 324) on the basis of an unspecified number of specimens. Zimsen (1964: 647) noted that there was one specimen originally from Kiel in the ZMUC. We have examined this specimen, an adult female, and we hereby designate it as the lectotype of the species. It has been rehydrated, and is in fairly good condition.

Comparative material of D. ovis . – Lectotype: female (cws 44.6 mm, cls 46.3 mm) ( ZMUC Cru 65), “India orientali”. Singapore : 1 male (cws 55.5 mm, cls 61.7 mm), 1 female ( ZRC 1965.10.14.33- 34), Siglap, coll. M. W. F. Tweedie, Jun.1934; 1 female (cws 52.1 mm, cls 57.9 mm) ( ZRC 1987.456 ), Bedok, coll. Singapore Fisheries Research Station , 6 Dec.1956; 1 juvenile ( ZRC 1985.141 ), south of Bedok , station B60, 21-22 fathoms, coll. Singapore Fisheries Research Station , Jun.1963; 1 male ( ZRC 1988.2198 ), Siglap, coll. R. D. Purchon, 9 Feb.1952; 1 juvenile female ( ZRC 1965.10.14.27), Siglap, coll. M. W. F. Tweedie, June 1934; 1 male ( ZRC 1987.1047 ), Marine Parade, East Coast , coll. 22 Apr.1960; 1 juvenile female ( ZRC 1984.5599 ), Changi Point, coll. 9 May.1982; 1 female ( ZRC 1995.446 ), Changi Point, coll. P. K. L. Ng, Jun.1993; 1 male ( ZRC 1996.2084 ), off Changi Point, coll. C. M. Yang, 19 Jan.1987; 3 juveniles ( ZRC 1985.135 - 137 ), shoal west of Raffles Lighthouse , station B28, 5-6 fathoms, coll. Singapore Fisheries Research Station , Jun.1963; 3 juveniles ( ZRC 1985.138 - 140 ), outer shoal, east of Sentosa island , station B25, 6 fathoms, coll. Singapore Fisheries Research Station , Jun.1963; 2 males ( ZRC 1984.5597 - 5598 ), East Coast , coll. P. K. L. Ng, May.1982; 1 female ( ZRC 1984.5596 ), East Coast , coll. P. K. L. Ng, Dec.1982; 3 females ( ZRC 1981.9.2.36- 38), East Coast , coll. P. K. L. Ng, Mar.1981; 1 male ( ZRC 1981.9.2.18), off East Coast Lagoon , coll. P. K. L. Ng, Mar.1981. SOUTH CHINA SEA: 1 male, 2 females ( ZRC 1984.168 - 170 ), near Horsburg Lighthouse, coll. Hee Huat, 26 Nov.1982; 2 males, 1 female ( ZRC 1984.6345 - 6347 ), near Horsburg Lighthouse, coll. Hee Huat, 10 Sep.1983; 2 males (larger cws 54.1 mm, cl 54.0 mm, cls 58.7 mm) ( ZRC 1984.6343 - 6344 ), 150 miles off Singapore, coll. Hee Huat, 19 Aug.1983. Peninsular Malaysia: 2 juvenile males, 4 juvenile females ( ZRC 1984.6431 - 6436 ), Kuala Johor, Johor, coll. 17 June 1954; 1 male ( ZRC 2001.1307 ), Pulau Perhantian, Terengganu, coll. 16 May.1976; 1 female ( ZRC 1999.1261 ), Tanjong Telek, Penang , coll. S. Teo et al., 13 Dec.1993; 2 juveniles ( ZRC 1988.2199 - 2200 ), Penang Straits, 2-4 fathoms, coll. Apr.1935; 1 male, 1 female ( ZRC), Andaman Sea, between Penang and Langkawi, coll. C. P. How & C. O. Lau, 12 Nov.1991; 3 males, 2 females ( ZRC), Pontian, Johor, coll. C. M. Yang, 31 Mar.1991. Thailand: 1 male ( ZRC 1998.1135 ), 1 female ( ZRC 1999.142 ), Andaman Sea, Pichai Fish Port, Phuket, coll. S. Chaitiamvong, Dec.1998; 8 males, 1 female ( ZRC 1999.143 ), Andaman Sea, Pichai Fish Port, Phuket, coll. H. H. Tan et al., Apr.1999; 3 males, 1 female ( ZRC 2000.761 ), Andaman Sea, Pichai Fish Port, Phuket, coll. N. K. Ng et al., 17-20 Jan.2000; 1 male, 1 female ( ZRC 2000.827 ), Andaman Sea, Pichai Fish Port, Phuket, coll. P. K. L. Ng, 3-6 May.2000; 1 male ( ZRC 2001.1059 ), Andaman Sea, Pichai Fish Port, Phuket, coll. 12 Feb.2001; 3 males, 2 females ( ZRC), Andaman Sea, Pichai Fish Port, Phuket, coll. C. Y. Lai, 22-25 Aug.2002; 3 males, 2 females ( ZRC), fish port, Pattani Bay, Gulf of Thailand, coll. D. C. J. Yeo, 20 Feb.2003. India: 1 female ( ZRC 2001.857 ), Porto Novo, river mouth of Vellar Estuary, Tamil Nadu, coll. N. K. Ng, 7 Mar.2001; 1 male (cws 47.3 mm, cls 51.7 mm, with sacculinid infestation), 2 females ( ZRC 2001.905 ), Tranquebar, Tamil Nadu, coll. N. K. Ng & A. S. Fernando, 16-24 Mar.2001; 1 male, 2 females ( ZRC 2001.906 ), Tranquebar, Tamil Nadu, coll. N. K. Ng & A. S. Fernando, 16-24 Mar.2001.

Figures

Fig. 3. Doclea canalifera Stimpson, 1857 (= D. japonica Ortmann, 1893). G1s. A, B, male, Vietnam (after Wagner, 1986: Figs. 6, 7); C, male, Japan (after Wagner, 1986: Figs. 5); G, H, male (cws 24.9 mm, cls 29.8 mm) (ZRC 1998.512), Taiwan; I, J, male (cws 48.5 mm, cls 52.8 mm) (ZRC 1998.185), Taiwan; K-M, male (cws 34.9 mm, cls 40.9 mm) (IOCAS S61-39), South China Sea. A, C, K, ventral view of right G1; B, distal part of right G1, ventral view; C, G, I, ventral views of left G1s; D, H, J, dorsal views of left G1s; E, distal part of left G1, dorsal view; F, distal part of left G1, ventral view; L, distal part of right G1, ventral view; F, distal part of right G1, dorsal view. Scales: A, C-M = 1.0 mm; B = 0.5 mm.

Fig.4. Vulvae.A, Doclea canalifera Stimpson, 1857 (= D. japonica Ortmann, 1893), ovigerous female (cws 60.3 mm, cls 66.1 mm) (ZRC 2001.55), Taiwan;B, Doclea ovis (Fabricius, 1787), ovigerous female (cws 52.1 mm, cls 57.9 mm) (ZRC 1987.456), Singapore.

Fig. 5. Doclea ovis (Fabricius, 1787). G1s. A, male, Peninsular Malaysia (after Wagner, 1986: Fig. 4); B, male, India (after Wagner, 1986: Fig. 3); C, D, male (cws 55.5 mm, cls 61.7 mm), (ZRC 1965.10.14.33-34), Singapore (modified from Ow-Yang, 1963). A, B, ventral view of right G1; C, distal part of left G1, ventral view, setae not drawn; D, distal part of left G1, dorsal view, setae not drawn. Scales: A, B = 1.0 mm; C, D = 2.5 mm.