Heikeopsis japonica (von Siebold, 1824 )

Peter, Danièle Guinot, L., Peter K., Naruse, Ng Tohru & Mazancourt, Valentin de, 2024, The identity of the iconic Japanese ‘ Heike-gani’, Heikeopsis japonica (von Siebold, 1824) (Crustacea, Decapoda, Brachyura, Dorippidae), Zoosystema 46 (31), pp. 775-811 : 780-804

Heikeopsis japonica (von Siebold, 1824)

( Figs 1-19 )

Doripe [sic] Japonica von Siebold, 1824: 14 (see footnote 5); 1826: 8; 1850: xiii (Shimonoseki or Nagasaki, see below). — Stimpson 1858: 163 (Hakodadi [sic, Hakodate]). — Herklots 1861: 137 ( Japan). — Ives 1891: 216 ( Japan). — Serène 1937: 77 (‘Indochine’).

Dorippe callida – De Haan 1839: pl. 31, fig. 1 [Not Dorippe callida Fabricius, 1798 ].

Dorippe japonica – De Haan 1841: 122, 227 ( Japan). — Nees von Esenbeck 1825: 87 (Shimonoseki). — Nishimura & Suzuki 1971: unnumbered fig in p. 102 ( Japan). — Miers 1886: 327, 328 ( Japan, near Kobe). — Stebbing 1893: 132, fig. 10 (reproduction of De Haan’s figure). — Rathbun 1902: 31 ( Japan, Wakanoura, Kii). — Terazaki 1902: 87, unnumbered drawing in p. 87 [ Japan and Korea]. — Anonymous 1904: 55, pl. 51, fig. 2 ( Japan). — Doflein 1904: 292 ( Japan). — Stimpson 1907: 167 (Hakodadi [sic, Hakodate]). — Parisi 1914: 302 ( Japan). — Ihle 1916: 153, 156 (cit.). — Urita 1918: 161 ( Japan: Kagoshima Prefecture; Korea). — Balss 1922: 118. — Maki & Tsuchiya 1923: 126, pl. 14, fig. 2 (‘Formose’, i.e., Taiwan). — Urita 1926: ii, 40 ( Japan: off Sibusi, Oshumi, Kagoshima Prefecture; Teuchi, Shimo-koshiki-shima). — Ishikawa Prefecture 1928: 55, pls. 52, 53 ( Japan). — Rathbun 1931: 99 [ China: Tsimei (= Jimei), Amoy (= Xiamen), Foochow (= Fuzhou)]. — Shen 1931: 101, pl. 6, figs 1, 2 (Shaukiwan District and Honkong); 1932: 11, figs 6, 7a-e (North China Sea: Liaotung Peninsula; Liaotung Bay, Peichihli Bay, Shantung Peninsula); 1937a: 169, 171 (North China); 1937b: 305 (list of species from North China); 1940a: 213 ( Hong Kong: Shaukiwan, Cheung Chau); 1948: 105 ( China: Shantung Peninsula). — Yokoya 1933: 108, 214 (East of Owashi, east coast of Kii Peninsula). — Kamita 1934: fig. 1 ( Korea); 1935: 62 ( Korea); 1936: 30 (Korean Strait); 1941a: 28, figs 5, 6 ( Korea); 1941b: 232, table ( Korea); 1963: 21 (southern part of Japan Sea: Oki Islands). — Sakai 1934: 283 (Nagasaki); 1936: 41, fig. 5 ( Japan); 1937: 72, pl. 10, fig. 1 ( Japan: Nagasaki, Onomiti, Yasima, Tosa Bay; Korea: Zinsen); 1940: 49, fig. 3 (‘common to Japan, China and Manchoukuo’). — Lin 1949: 12 (Taiwan). — Sakai 1956: 6, 21, fig. 7 (reproduction of De Haan’s figure); 1965: 21 (list including Japan, Korea and China). — Kaneko 1958: 332, 336, pl. 15, fig. 10. — Miyake 1961a: 13 (sea around Amakusa); 1961b: 165, 170 (Kyushu: Sea of Ariake). — Miyake et al. 1962: 126 (Amakusa). — Chang 1963: 1 (Taiwan). — Shen & Liu 1963: 144 (list, Chinese Seas). — Serène 1968: 40 (cit.). — Holthuis & Sakai 1970: 46, 90, 116, 309, pl. 8, fig. 3 (reproduction of De Haan’s fig.). — Kim 1970: 9 (list, Korea). — Miyake & Takeda 1978: 2, 33 ( Japan: Amakusa). — S. L. Yang 1986: 152 ( China). — Zhou & Sun 1986: 223 ( China, coast of Liaoning Province). — Dai et al. 1986: 48, fig. 24.1, pl. 5, fig. 6 ( China seas).

Dorippe cf. japonica – Kaneko 1958: 331.

‘Crabes fort curieux’ – Fauvel 1880: 31 ( China: Ningbo, Zhejian Province).

Dorippe sima – Fauvel 1880: 196 (not Dorippe sima H. Milne Edwards, 1837 ) (Wu-sha, island near Zhoushan, Zhoushan Islands).

Dorippe histrio – Rathbun 1931: 99. — Shen 1940b: 70, 76 [Not Dorippe histrio Nobilili, 1903 ] (South China: Yen t’ing, Chuanshih).

Doryppe japonica – Dawydoff 1952: 139 (South China Sea: Paracel Islands).

Neodorippe (Neodorippe) japonica – Serène & Rohmimohtarto 1969: 13, figs 19, 20A, B, pl. 2A, 5C, 6Af (Nhatrang Bay, Vietnam; Nagasaki, Japan). — Kim 1973: 290, 610, figs 85, 87, pl. 76, fig. 57a, b ( Korea); 1977: 204 (list, Korea). — Kim et al. 1981: 285, 291 (list, Korea). — Kim & Kim 1982: 136, table 1 ( Korea Strait, Yellow Sea). — Sakai 1976: 61, pl. 22, fig. 1 (Inland Sea; Saga Prefecture; Shimabara Peninsula). — Yamaguchi et al. 1976: 34 ( Japan: vicinity of Aitsu Marine Biological Station). — Morita 1977: 16, pl. 2, figs 1-4 (Holocene fossil, Japan: Osaka City). — K. Sakai & Nakano 1983: 81 ( Japan: Shikoku Island).

Neodorippe (Neodorippe) japonica var. taiwanensis Serène & Romimohtarto, 1969 : figs 21, 22, pl. 5A, B, D ( Taiwan: Chilung, type locality).

[Japanese name] – Imajima et al. 1970: 16, coloured fig. ( Japan). — Sakai 1980: 4, fig. 12 ( Japan).

Neodorippe japonica – Takeda 1975: 121 (coloured figures); 1982: 93 (coloured figure) ( Japan); 1983: 121 (coloured figure) ( Japan). — Miyake &Takeda 1978: 33 ( Japan);. — Terada 1981: 21-28, 30, 31, figs 1A, 2A, 3A, 4A (zoeae, Japan: east coast of Honshu Island and Enshu Nada, Shizuoka Prefecture). — Sugano 1981: 124-131 (as Heike-gani), 186, fig. 39 ( Japan). — Horikoshi et al. 1982: 126 (Tosa Bay). — Sakai 1985: 330 pro parte, figs 1, 3 top, not fig. 3 ( Japan and China).

Nobilum (Neodorippe) japonica – C. M. Yang 1979: 3 (cit.).

Nobilum (Neodorippe) japonica var. taiwanensis – C. M. Yang 1979: vii, 3 (Taiwan).

Nobilum japonicum taiwanense – Manning & Holthuis 1981: 31 (cit.).

Nobilum japonicum japonicum – Miyake 1983: 17, 198, pl. 6, fig. 1 ( Japan). — Muraoka & Konishi 1988: 125 (zoeae).

Nobilum arachnoides Manning & Holthuis, 1986: 364 , fig. 1d ( Japan: Inland Sea, near Kobe).

Nobilum japonicum – Chen 1986: 123, fig. 5.23-27 ( China: ‘from the coast of my country’).

Nobilum [sic] japonica – Yamaguchi et al. 1987: 8, pl. 1, fig. 10 (list, photo, Japan: Amakusa Islands).

Heikea japonica – Holthuis & Manning 1990: figs 29 (Jimei, Fukien Province, China), 30 ( Japan), 31 (Jimei), 32 ( Hong Kong), 33 ( Taiwan: holotype of Neodorippe japonica var. taiwanensis ), 34 (reproduction of 1839 De Haan’s fig.), 35 (reproduction of 1932 Shen’s fig.). — Yamaguchi & Baba 1993: 30 (list), 300, fig. 90- A, 90-B ( Japan: list of lectotype and paralectotypes). — Wada 1995: 383, pl. 102-2. — Fransen et al. 1997: 83 (list of lectotype and paralectotypes deposited at RMNH). — Ng & Huang 1997: 267, figs 3F, 4B (Taiwan). — Muraoka 1998: 16. — Umemoto & Karasawa 1998: 11, fig. 7; Japan (Holocene fossil, Japan: Aichi Prefecture). — Takeda et al. 2000: 139, table 1 (list; possible record from Sagami Bay). — Itani & Fujihara 2001: 47, fig. 1 (carrying behaviour). — Yamaguchi & Holthuis 2001: 30, pl. 5, figs 41, 42 (pictures of Heikea japonica ). — Chen & Sun 2002: 222, fig. 94 (various parts of China, including Taiwan, Nansha, South China Sea). — Marumura & Kosaka 2003: 23 (Shizuoka, Japan; Taiwan). — Yamaguchi & Baba 2003: 3. — Takeda & Ueshima 2006: 67 (Kyushu, Bingo (eastern Hiroshima), Bicchu (western Okayama), Kii, Sagami Bay, Incheon) [list]. — Takeda et al. 2006: 190. — Machida et al. 2009: 535, pl. 1B. — Takigawa 2017: 102, fig. 1 (historic study).

Heikea arachnoides – Holthuis & Manning 1990: 72, figs 27, 28 ( Japan: Inland Sea, near Kobe and Inland Sea without more details). — Ng & Huang 1997: 267, figs 3E, 4A (lIan County, northeastern Taiwan). — Takeda et al. 2000: 139, table 1 (list). — Chen & Sun 2002: 220, fig. 93, pl. 1-4 (Taiwan).

Dorippe (Neodorippe) japonica – Dai & S. L. Yang 1991: 54, fig. 24.1, pl. 5, fig. 6 ( China seas).

Heikea japonicum [sic] – Ng et al. 2001: 8 (Taiwan).

Heikeopsis japonica – Ng et al. 2008: 59 (list). — Ko & Lee 2013: 19, figs 10, 11 ( Korea). — Wang et al. 2013a: 513, table 2; 2013b: 1392. — Ng et al. 2017: 36, fig. 3a. — Wang et al. 2017: Appendix 1. — Takeda et al. 2011: 34, figs 5-14 ( Japan: around Tottori Prefecture). — Wu et al. 2016: Appendix 1 ( Japan: Yellow Sea, and China: Bohai). — Davie 2015: fig. 71-2.31.E. — Takeda et al. 2019: 13. — Sasaki 2019: 7788 (references). — Luque et al. 2021: fig. 5a. — Khim et al. 2021: table S2 (Korean Peninsula). — Lee et al. 2021: table S2 ( Korea).

Heikeopsis japonicus [sic] – Luo et al. 2015: table S (Shandong, China).

Heikeopsis arachnoides – Ng et al. 2017: 36 (Taiwan).

Heikeopsis japonica and? H. japonica Guinot 2023: 225 , 228, 238, 266-274, 323, 355, 356, 360, figs 1, 2A, 19, 31D, 32D, 35E, 38, 39 (revision).

TYPE MATERIAL AND TYPE LOCALITY

The lectotype and paralectotypes of Heikeopsis japonica were selected by Yamaguchi & Baba (1993: 300, figs 90-A. a-1, a-2, b, d-f, 90-B, as Heikea japonica ) from the type series labelled ‘Types, Japan, 1823, Leg. P. H. von Siebold’, deposited in Leiden ( RMNH.CRUS.D.822) (see Fransen et al. 1997: 83, as Heikea japonica ). The lectotype is the male indicated with an arrow by Yamaguchi & Baba (1993: fig. 90-A, a-2). Photographs of the lectotype and many paralectotypes were kindly made and sent to us by C. H. J. M. Fransen. This material was subsequently re-examined and photographed by P. K. L. Ng.

The type locality of Heikeopsis japonica should be Shimonoseki, as the type specimen(s) examined by von Siebold was a part of J. Cock Blomhoff’s collection, and von Siebold (1824: 14, footnote 3) noted on the species as “Ex urbe Zimonozeki affertur, fabulâque antiquâ comitata” [= It is brought from the city of Zimonozeki (= Shimonoseki), accompanied by an ancient legend] (see Introduction and also Takigawa 2017). Although the locality mentioned by De Haan (1841: 122, as D. callida ) is Nagasaki, neither “Zimonozeki” nor “ Nagasaki ” is present on the labels of the lectotype and paralectotypes ( Yamaguchi & Baba 1993: 300, as Heikea japonica ; Fransen et al. 1997: 83, as Heikea japonica ). Holthuis & Manning (1990: 77) only indicate the following for five syntypes: ‘ Japan (probably near Nagasaki), 1823, P.F. von Siebold’. It is also possible that the mythology of Heike and H. japonica at Shimonoseki was so strong that J. Cock Blomhoff might have believed his H. japonica specimen(s) must have come from this location. In any case, as the distance between Shimonoseki and Nagasaki is only some 160 km, populations from the two localities should belong to a same species.

MATERIAL EXAMINED. — Japan. Shimabara and Ariake Bay, Nagasaki • 1 ♂ 19.5 × 20.1 mm, 1 ovigerous ♀ 23.7 × 25.7 mm; Tomioka , Shimabara Bay ; 29.V.1957; ZLKU 8337-8338 • 1 ♂ 17.5 × 17.7 mm, 3 ♀ 15.7 × 16.3 – 20.2 × 21.4 mm; Aratsu , Ariake Bay ; 4.VI.1957; ZLKU 8350-8353 • 1 ♂ 19.5 × 19.5 mm; Miike Bathing Beach , Omuta , Fukuoka, Ariake Bay ; coll. T. Watanabe; 6.IV.2004; OMNH Ar 7003 • 1♂ 21.3 × 23.7 mm; Ariake Bay , Nagasaki; coll. T. Sakai, 1969; ZRC 1969.5 .5.1 • 1 ♀ 19.6 × 20.7 mm; Ariake Bay , Nagasaki, Japan ; coll. T. Sakai; 1969; ZRC 1969.5 .5.2 • 4 ♂ 6.0 ×5.8 – 25.9 × 26.4 mm, 3 ♀ 17.1 × 17.3 – 21.5 × 22.8 mm; off Rokkaku River , Saga, Ariake Bay ; coll. D. Uyeno; 15.VI.2007; RUMF-ZC-7646. Kumamoto • 1 ovigerous ♀ 23.9 × 25.3 mm; off Kawaguchi , Kumamoto, Kumamoto; coll. H. Yoshigou; 27.VII. 2009; HMNH-C887. Kanmon Strait • 1♂ 22.6 ×24.0 mm; Mekari Beach , Moji , Fukuoka, opposite Shimonoseki ; coll. J. Fujii; X.1954; ZLKU 9425 . Inland Sea : Hiroshima • 2♀ 8.1 × 8.2 mm, 13.3 × 13.5 mm; river mouth of Hongou River , Minamimatsunaga , Fukue , Hiroshima; coll. H. Yoshigou; 21.VII.2018; HMNHC1434. Inland Sea : Ehime • 1 ♀ 17.9 × 18.6 mm; Off Kamo River , Saijo , Ehime; coll. S. Ishida et al.; 30.VIII.2011; OMNH Ar 9232 • 1 ♀ 24.9 × 26.8 mm; Hiuchi Nada , Niihama , Ehime, trawling; coll. H. Yamazaki; 12.XII.2015; OMNH Ar 10085. Inland Sea : Kagawa • 1♂ 20.1 × 21.5 mm; Teshima Island , Tonosho , Kagawa; coll. S. Miyake; 4.VII.1934; ZLKU 8627 . Inland Sea • 1 ♂ 15.8 × 16.7 mm [holotype of Nobilum arachnoides Manning & Holthuis, 1986 ]; Inland Sea , near Kobe , Japan ; 15-91 m; coll. ‘ Challenger Expedition’ , 1875; NHM 84.44 • 1♂ 12.2 × 12.5 mm; Inland Sea , Japan ; 15-92 m; coll. R. Gordon Smith; 1903; NHM 1903.6 .7.10 • 1 ♂ 15.2 × 15.7 mm; Inland Sea , Japan ; 15-92 m; coll. R. Gordon Smith; 1903; NHM 1903.6 .7.5. Osaka Bay. 7♂ 20.9 × 20.3 – 27.8 × 29.2 mm; 6 ♀ 22.0 × 23.9 – 27.0 × 28.7 mm; off Sennnan , Osaka Bay ; trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 23.III.1976; OMNH Ar 550-562 • 3 ♂ 23.4 × 24.0 – 24.7 × 24.8 mm, 1 ♀ 24.2 × 26.5 mm; off Misaki , Sennnan , Osaka Bay ; trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 24.III.1976; OMNH Ar 738-741 • 3♂ 20.8 ×21.8 – 26.0 × 27.5 mm; 5 km off Sennnan , Osaka Bay ; trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 24.III.1976; OMNH Ar 742-744 • 4 ♂ 17.9 × 18.5 – 20.4 × 21.0 mm, 3 ♀ 21.6 × 22.6 – 25.9 × 27.2 mm; off Sennnan ; Osaka Bay ; trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 24.III.1976; OMNH Ar 746-752 • 3♂ 23.3 ×24.1 – 24.8 × 26.0 mm; off Sennnan , Osaka Bay ; trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 24.III.1976; OMNH Ar 754-756 • 1 ovigerous ♀ 21.2 × 22.9 mm; off Tanigawa , Tanagawa , Misaki , Sennnan , Osaka Bay ; - 20 m; coll. Y. Nabeshima; 3.VII.1981; OMNH Ar 2551 • 1 ♂ 25.6 × 26.1 mm, 1 ♀ 22.7 × 24.8 mm; N Kansai International Airport; Osaka Bay ; 34°29’N, 134°17’30”E; coll. K. Hatooka; 19.IX.1995; OMNH Ar12010 • 1♂ 20.8 × 20.9 mm; Osaka Bay; coll. Osaka Prefectual Fisheries Experimental Station ; early 1970s; OMNH Ar12349 • 2♂ 22.5 × 24.5, 25.6 × 26.6 mm, 1 ♀ 25.2 × 28.4 mm; Osaka Bay; coll. Osaka Prefectual Fisheries Experimental Station ; OMNH Ar12350 • 3 ♂ 18.3 ×18.5 – 24.8 × 26.1 mm, 2♀ 25.0 × 27.5, 26.0 × 28.4 mm; 5 km off Sennnan, Osaka Bay, coll. Osaka Prefectual Fisheries Exper - imental Station; 24.III.1976; OMNH Ar12351 • 10 ♂ 19.3 × 20.3 – 24.5 × 25.3 mm; 6 ♀ 23.4× 25.3 – 28.1 × 30.6 mm; off Sennnan, Osaka Bay, trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 24.III.1976; OMNH Ar12352 • 4 ♂ 23.5 ×24.7 – 26.4 × 28.0 mm, 9 ovigerous ♀ 19.5 × 20.7 – 26.5 × 28.9; 1-5 km off Sennnan, Osaka Bay; trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 17.VI.1976; OMNH Ar12353 • 10 ♂ 17.1 ×16.8 – 25.7 × 27.2 mm, 13 ♀ 22.0 × 23.8 – 29.3 × 31.8; off Sennnan, Osaka Bay; trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 24.III.1976; OMNH Ar12354 • 2 ♂ 21.1× 21.8 – 25.8× 27.4 mm, 9 ♀ 22.7 ×24.4 – 26.3 × 28.4 mm; 5 km off Sennnan, Osaka Bay; trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 24.III.1976; OMNH Ar12355 • 4 ♂ 19.5 × 19.7 – 23.9 × 24.5 mm, 2 ♀ 25.0 × 27.1, 27.5 × 30.6 mm; off Sennnan, Osaka Bay; trawling; coll. Osaka Prefectual Fisheries Experimental Station ; 24.III.1976; OMNH Ar12356. Kii Channel • 5 ♂ 20.4 × 22.6 – 22.0 × 24.3 mm, 2 ovigerous ♀ 24.1 ×27.3, 25.6 × 29.2 mm; off Yoshinogawa, Tokushima, Kii Channel; 34°3.489’N, 134°38.697’E; coll. K. Sakai; no date; SMF 57849 • 15 ♂ 17.0 × 18.5 – 24.2 × 25.6 mm, 8 ovigerous ♀ 22.0 × 25.0 – 25.8 × 28.9 mm; off Okinose, Tsuda-Tokushima, Kii Channel; coll. K. Sakai; 14.II.2002; SMF 57854 • 2 ♂ 19.3 ×20.1, 22.2 × 23.3 mm, 1 ♀ 23.3 × 25.1 mm; off Komatsu Island , Tokushima, Kii Channel; coll. K. Sakai; 9.VII.1991; SMF 57864 . Unknown localities • Lectotype, ♂ 27.4 × 26.0 mm, paralectotypes, 1 ♂ 14.4 × 14.2 mm, 5 ♀ 17.1 × 18.2, 28.2 × 24.9 mm; coll. von Siebold; RMNH.CRUS.D.822 • paralectotypes, 4 ♂ 13.2 × 13.2 – 18.9 ×20.0 mm, 3 ♀ 16.3 ×17.5 – 18.5 × 19.3 mm; coll. von Siebold; RMNH.CRUS.D.1605 • 1 ♂ 25.0× 27.3 mm, 1 ♀ 23.5 × 26.7 mm; Chaffanjon; dry condition; MNHN entry 174-1896; E.-L. Bouvier det. 1899 Dorippe japonica ; MNHN-IU-2000-4091 (= MNHNB4091 ) • 1 ♀ 16.8 × 18.6 mm; dry condition; Japan Sea; coll. von Siebold; MNHN-IU-2000-34 (= MNHN-B34 ).

Korea • 1 ♂ 15.7 × 16.2 mm; fishery market, Oenardo Port, Jeollanam-do, South Korea ; coll. 20.X.2001; SNUC 271101 #005 • 1 ♂ 16.9 × 17.1 mm; from net of fishery ship, Saemangeum, Buan-gun, Jeollanam-do, South Korea ; coll. 22.VIII.2003; SNUC 271101 #006 . Taiwan • 1 ♂ 21.4 × 22.5 mm; Tahsi, Ilan, northern Taiwan ; coll. J. C. Y. Lai & N. K. Ng; 1.XII.2003; ZRC 2004.0636 • 1♂ 21.3 × 23.7 mm; Tahsi, Ilan, Taiwan ; coll. P. K. L. Ng; 3-4.VIII.1996; ZRC 1997.0392 • 3 ♂ 19.9 ×20.5 – 20.4 × 22.4 mm, 2 ♀ 18.9 × 22.2 – 21.1 × 24.2 mm; Tahsi, Ilan province, northern Taiwan , from fishermen catches; coll. P. K. L. Ng; 3-4.VIII.1996; ZRC 1997.0622 • 1 ♂ 22.0 × 23.2 mm; Toucheng, Ilan Province; northeastern Taiwan , Taiwan ; coll. C.-H. Wang; 11.XI.1990; ZRC 1995.0611 • 3♂ 17.9 × 18.8 – 23.5 × 25.3 mm, 1 ♀ 21.6 × 24.5 mm; Tashi, Ilan Province, northern Taiwan ; coll. K. X. Lee; 2000; ZRC 2001.0013 • 1 ovigerous ♀ 21.2 × 23.9 mm; Nangfangao, Su-Ao, Ilan County, northern Taiwan ; coll. P. K. L. Ng; 28.V.1997; ZRC 1998.488 • 3 ♀ 18.6 × 20.5 – 25.2 × 28.1 mm; Tashi port, Ilan Province, northern Taiwan ; coll. P. K. L. Ng; 17.XI.1997; ZRC 2021.0727 • 1 juvenile ♂ 9.3 x 9.2 mm, 1 juvenile ♀ 9.5 x 9.0 mm; off Kueshan Island, off Tahsi Port, Ilan Province , northern Taiwan ; coll. P. K. L. Ng & P.-H. Ho; 24.V.2024; ZRC 2024.0092 .

China. Qingdao and Shandung • 2 ♂ 19.3 × 19.4, 23.9 × 24.6 mm, 2 ovigerous ♀ 25.1×27.0 mm, 26.4× 28.5 mm, 1 ♀ 21.6× 24.1 mm; Tuandao, Qingdao; from shallow water fishermen nets; coll. P. K.

L. Ng ; 23-25.VIII.2002; ZRC 2002.0491 • 1 ♂ 19.1 × 18.9 mm; in fishery trawl; Qingdao, Shandong Province, northern Chi - na; coll. students; 16.IV.2022 [donated by Li Xinzheng]; ZRC 2023.0043 • 1♂ 17.5 × 18.4 mm; same data as for preceding; MNHN-IU-2024-6082 • 1♂ 19.8 × 20.2 mm, 1 ovigerous ♀ 20.9 × 22.8 mm, 1 ♀ 21.3 × 22.8 mm; Dingziwan Harbour, Jimo, Qingdao , Shandong Province, northern China; coll. Wen Zou; 16.IV.2022 [donated by Li Xinzheng]; ZRC 2023.0044 • 1♂ 22.6 × 23.6 mm, 1 ovigerous ♀ 21.6 × 22.6 mm; same data as for preceding; MNHN-IU-2024-6083 • 1 ♂ 19.7 × 19.9 mm, 1 ovigerous ♀ 22.2 × 24.1 mm; off Qingdao, Tuanda , from inshore fishermen; coll. P. K. L. Ng; 23-25.VIII.2002; ZRC 2002.0491 • 1 ♂ 18.9 × 19.1 mm, 1 ♀ 21.3 × 23.1 mm; Laizhou City , Shandong; coll. Pan Da; VIII.2010; ZRC 2023.0037 • 1 ♂ 29.0 × 30.3 mm, 1 ovigerous ♀ 24.0 × 26.6 mm; North China Sea ; 10 m; soft bottom; coll. trawl; 10.V.1959; H. Chen det. 1987; MNHN-IU-2018-5197 (= MNHN-B18801 • 1 ovigerous ♀ 24.3 × 26.7 mm; in fishery trawl, Subei Shoal , Jiangsu Province, northern China; coll. 27.IV.2019; ZRC 2023.0045 . Jiangsu, Shanghai • 2♂ 18.7 ×18.9, 18.8 × 19.0 mm; Qi Dong , Shanghai; coll. Y. Y. Li; 1.V.1996; ZRC 1998.330 . Guangdong and Nanao • 5 ♂ 12.8 × 13.0 – 22.6 × 23.2 mm, 3 ♀ 21.0 × 20.9 – 26.5 × 28.6 mm; Qianjiang fish port, Nanao County, Guangdong, southern China; coll. Y. Cai & N. K. Ng; 14.XI.1998; ZRC 1999.0469 • 1 ♂ 13.1 × 13.3 mm; Houzhai market, Nanao County , Guangdong; coll. Y. Cai & N. K. Ng; 12.XI.1998 ZRC 1999.0467 .

Hong Kong • 7♂ 22.1 × 20.8 mm, 23.8 × 22.6 mm, 3♀, station W1; 22°11.259’N, 113°55.232’E – 22°12.285’N, 113°59.086’E; 7.4- 19.9 m; coll. K. Wong et al.; University of Hong Kong trawls; 30.VII.2018; ZRC 2021.0744 • 1♂ 21.3 × 22.0 mm; station E1, northeast of New Territories ; 22°26.990’N, 114°16.843’E – 22°29.456’N, 114°24.886’E; 14.8-23.6 m; coll. K. Wong et al.; University of Hong Kong trawls; coll. 17.III.2014; ZRC 2021.0745 • 1 ♂ 17.0 × 17.5 mm; station E1, northeast of New Territories ; 22°26.990’N, 114°16.843’E – 22°29.456’N, 114°24.886’E; 14.8- 23.6 m; coll. K. Wong et al.; University of Hong Kong trawls; 10.XI.2018; ZRC 2021.0746 • 1 ♂ 13.6 × 14.3 mm; station S1, southeast of Hong Kong Island ; 22°09.967’N, 114°16.442’E – 22°12.951’N, 114°18.552’E; 9.4-34.0 m; coll. K. Wong et al.; University of Hong Kong trawls; 14.XI.2012; ZRC 2021.0747 • 1♂ 20.3 × 20.6 mm; station SW3, northwest of Lantau Island ; 22°14.517’N, 113°50.099’E – 22°17.062’N, 113°52.152’E; 6.2- 27.3 m; coll. K. Wong et al.; University of Hong Kong trawls; VIII.2007; ZRC 2021.0748 • 1♂ 15.8× 16.4 mm; station W2, southwest of Lantau Island ; 22°11.264’N, 113°51.358’E – 22°12.926’N, 113°54.570’E; 4.0- 11.6 m; coll. K. Wong et al.; University of Hong Kong trawls; 27.VIII.2012; ZRC 2021.0749 • 1 ovigerous ♀ 23.7 × 26.2 mm; station E2; station E2; northeast of New Territories ; 22°29.537’N, 114°20.802’E – 22°30.275’N, 114°22.018’E; 7.4-23.0 m; coll. K. Wong et al.; University of Hong Kong trawls; 23.VII.2018; ZRC 2021.0777 • 1 ♀ 24.9 × 26.7 mm; station E4; northeast of New Territories , Hong Kong; 22°27.094’N, 114°15.629’E – 22°28.676’N, 114°18.093’E; 9.7-21.8 m; coll. K. Wong et al.; University of Hong Kong trawls; 30.VII.2012; ZRC 2021.0778 .

Vietnam • 1 ♂ 18.4 × 19.4 mm; Nhatrang , Vietnam, on muddy bottom; by trawlers; X.1955; ZRC 1969.12 .18.1 .

DESCRIPTION (MODIFIED FROM HOLTHUIS & MANNING 1990) Carapace

Carapace 0.89-1.19 times (mean 1.06, n = 239) broader than long, convex.Dorsal surface sculptured, with delineated human facies. Frontal region distinctly setose, remainder of carapace much less so. Main grooves very distinct. Mesogastric region low, protogastric region lacking distinct tubercles or oblique swellings. Urogastric area depressed, with a median tubercle, may be salient or low, or not discernible. Branchial regions swollen, each with oblique dorsal carina. Front consisting of two blunt teeth separated by wide shallow U-shaped emargination. Outer margin of front separated from inner orbital lobe by concavity; inner orbital lobe straight or sinuous. Postorbital fissure closed or narrowly open in some specimens. Outer orbital lobe unarmed, inconspicuous. Exorbital tooth well developed, slender or blunt, falling short of front. Suborbital margin with strong exorbital tooth and short rounded inner orbital tooth, evenly concave, margin granular but unarmed. Antero- and posterolateral margins not demarcated, lacking lateral branchial spine. Carapace posterior rim not extending at all laterally along posterolateral margins and lined posteriorly by narrow strip, thinner medially than laterally, thus slightly concave, in males as in females.

Cephalic structures

Eyes short and stout, widening distally; cornea ventrolateral. Antennule entirely folded into fossa, with basal peduncle more or less long. Antennae: article 2 + 3 quadrate, hardly moveable; article 4 short, bent outwards; article 5 only slightly longer than preceding, bent outwards; both articles 4 and 5 widened and lying nearly horizontally on eyestalk; flagellum long.

Oxystomatous disposition

Openings of exhalant channels scarcely visible in dorsal view.

Chelipeds, P1

Chelipeds equal in size and shape in young males and females but right chela greatly inflated in adult males at variable sizes, with variously shaped and oriented swelling; chela may be inflated in males as small as CL 19.5 mm, usually inflated in males larger than CL 22 mm; inflated chelae usually lacking row of long setae dorsally and ventrally on palm and fingers; surface of palm smooth, even. Fingers of swollen male chela about 1.5 times as long as upper margin of palm; in females and young males fingers about 3 times length of palm; cutting edges of fingers with 9-12 equal teeth, smaller, blunter and fewer on inflated chela of large males. (See VARIATIONS, below).

Ambulatory legs, P2-P5

P2 and P3 (the longest) varying from long, slender, with both reaching beyond front with distal end of merus, to shorter and stouter ( Figs 3-5 ); without spines or with distinct, sometimes sharp granulation, with scattered short setae on surface; merus of P3 varying from 3.72-7.67 times (mean 5.76, n = 195) as long as high; dactyli of P2 and P3 as long as or slightly longer than their respective propodi; most of dorsal margin and at least half of ventral margin of dactyli fringed with setae. Propodi strongly flattened, not conspicuously carinate, but with shallow longitudinal groove on upper (posterior) and lower surfaces. Carpus with indistinct dorsal fringe of setae, shorter than propodus and almost half as long as merus. P5 merus slightly beyond base of merus of P3 and overreaching base of merus of P4.

Thoracic sternum

Thoracic sternum of male rather wide. Sternite 1 usually with small portion dorsally visible. Sternite 2 salient, with distinct straight external margins, and forming a quadrangular piece; sternite 3 oval and laterally extended, consisting of smooth coalesced median and submedian elevations, and salient curved margins; sternite 4 with median elevation; sternite 5 with marked longitudinal ridges; sternite 6 inflated, with two strong oblique ridges posteriorly; sternite 7 exposed, as long, oblique plate along each side of pleon. Sutures 4/5- 7/8 interrupted medially; suture 3/4 only visible laterally, deep and often ending in closed boutonniere (‘boutonnière’ in French) marked by a perforation; sutures 4/5 and 5/6 with short interruption points; suture 5/6 slightly curved backwards; suture 6/7 interrupted in males, but each end linked by low bridge; suture 5/6 interrupted in females, with each end linked by sulcus, sometimes membranous. Female thoracic sternum progressively tilted backwards at level of weak ridge of sternite 6. In females, fused portion of sternite 8 with erect axial spine, usually very salient but may be low, rarely absent.

Pleon and telson

Male pleon with somites 1, 2 and part of 3 dorsal; female pleon with somites 1-3 and part of 4 dorsaly exposed. All somites free. Male pleon more or less constricted at level of pleonal somite 5 and overhung by raised borders of sternopleonal cavity. Telson varying from triangular and slightly elongated to more flattened, with hat-shaped or rounded apex. Tip of telson not very far from suture 4/5. Female pleon smooth, with no sharp teeth or spines, each somite with median prominence; somites 3-5 crossed by marked smooth carina. (See VARIATIONS, below).

Pleonal locking mechanism by press-button

Locking buttons on posterior margins of sternite 5, often as spines. Sockets on pleonal somite 6 very deep and extending on most of length of somite; may be swollen and marked externally. Also effective in females, with locking prominences lying very close to vulvae.

Additional female pleonal-retention mechanism.

In females, strong retention by wide process of sternite 8 overhanging pleonal somite 2.

Male gonopore and penis

Male gonopore coxal. Coxo-sternal condition of penis, the most elaborate of all dorippids and similar to that of ethusids. Sternites 7 and sternite 8 close to one another for long distance (much longer than in any other dorippid), so penis very long, with elongated bulb prolonging into penis without clear demarcation, then long exposed inclined portion and shorter vertical portion covered by well-developed G1 protopodite; bulb and proximal inclined portion of penis clearly visible dorsally between sternite 7 and widely exposed sternite 8. (See VARIATIONS, below).

Gonopods

G1 without basal lobe; inverted C-shaped (in situ), stout proximally; its distal part slender and elongated, strongly bent and largely curved outward; apex elaborate and ending in two elongate, blunt-toped unequal lobes plus two subdistal processes ( Vehof 2020: fig. 11A, C, D).

G2 with strongly bent apex ( Vehof 2020: fig 11B). (See VARIATIONS, below).

Vulvae

Vulva at internal part of conspicuous sternal prominence close to sternal bulge of sternite 6, showing as long, extremely narrow, curved, vertically oriented slits, overhung by prominence; opening obliquely directed on submedian area of sternite 6.

Female reproductive system

Two ovaries and two seminal receptacles that open through the vagina and vulva onto thoracic sternite 6. These two sperm storage chambers (e.g., a single sperm storage organ on each side of the body) with a direct connection to the oviducts resembling the condition in other Eubrachyura, as does internal fertilisation ( Vehof 2020: 52, figs 4, 5A 6, 22; Guinot 2023: figs 35, 37).

COLOUR IN LIFE

In life, the typical morph is brown to dark brown on all its dorsal aspects, with the ambulatory dactyli maroon, with the adult male chelae cream coloured to white ( Fig. 1C, D ). The short-legged morph is similarly coloured but generally lighter brown ( Fig. 2 A-D, G, H), and in one specimen, the overall colour is just pale cream to dirty white ( Fig. 2E, F ).

VARIATIONS

Measurements of a large number of adult male and female specimens from Japan showed that the CW and CL are highly correlated, with females possessing a slightly wider carapace ( Fig. 9 ) (cf. males: Figs 7 A-F, H-L; 8A-E, H, I versus females: Figs 7G ; 8F, G ).

Adult males sometimes have distinctly asymmetrical chelipeds, with one of the chelae (usually the right) distinctly inflated ( Fig. 11 ). In larger adult male specimens, the right chela is swollen and fully grown at CL 23.4 mm and CW 23.9 mm (with one exception), a size range which is slightly larger than those from northern China (fully grown at CL 21.9 mm and CW 24.0 mm, ZRC 2002.0491, Qingdao; and CL 18.0 mm, CW 19.5 mm, cf. Shen, 1932) ( Figs 10 ; 11 ). This suggests that Japanese individuals may grow larger than northern Chinese individuals, which may affect comparison of their carapace proportions as well.

There are no obvious differences when large numbers of adult G1 and G2 structures from all the areas are compared. Ng & Huang (1997) had alluded that the distal folds of H. japonica and H. arachnoides differed slightly but noted that this was based on only a few specimens. The present study shows that the variation in the degree of curvature and structure of the distal folds varies too substantially to see any pattern between populations from Japan, Taiwan, southern China and Vietnam ( Figs 18 ; 19 A-G) and those from northern China (and Korea) ( Fig. 19 H-Q). The male specimen from Nagasaki ( ZRC 1969.5.5.1) is relatively large and, with a CW of 23.7 mm, it is similar in size to most other specimens from Japan and Taiwan. Its pleon, however, is relatively narrower longitudinally overall; pleonal somite 1 is distinctly narrower, somite 6 is relatively more elongated ( Fig. 16C, D ) and is similar to that of smaller subadult males (e.g., Fig. 16O, P ). In addition, its G1 does not appear to be fully developed ( Fig. 18 A-D), is distinctly shorter, somewhat soft and not well chitinised, and more closely resembles the condition in subadult or juvenile specimens from other locations (e.g., Fig. 18 Q-S). In male specimens of similar CW (or smaller), the G1 is already fully developed, being distinctly longer and the distal folds more prominently formed (e.g., Fig. 19 H-J, O-Q). The G1 of the type of Neodorippe (Neodorippe) japonica var. taiwanensis is unusual and we are not sure if it is similar to the situation for the Nagasaki male as the flaps, while long, are very flattened, appearing collapsed ( Fig. 18 I-K); we believe it may be due to the fact that the specimen was preserved before it had fully hardended after molting. The second author has observed the same situation with several specimens of Paradorippe australiensis (Miers, 1884) from the Arafura Sea in the Bogor Museum, where male specimens comparable in size to adult specimens have a poorly chitinised and short G1 with the distal parts poorly developed (unpublished information).

DISTRIBUTION

Heikeopsis japonica has a very wide distribution from Kyushu and western Honshu, Japan, Korea, Taiwan, northeastern to southern coast of China to Vietnam ( Sakai 1976; Kim 1973; Shen 1931, 1932; Serène & Romimohtarto 1969; Chen & Sun 2002; Takeda et al. 2011; Ng et al. 2017). Holthuis & Manning (1990: 82) wrote: “From this, and in the absence of subsequent substantiated records, we assume the following record to be erroneous: Hakodate ( Stimpson, 1858, 1907). We are unable to place the record by Parisi (1914) of Kujiukuri, Hitachi, reported by Balss as Kujinkuri (Hitachi); if this is Hitachi, at 36°35’N, 140°40’E, on the east coast of Honshu Island, the record certainly is erroneous. Parisi’s locality may be in Suruga Bay; we are unable to locate any records from that bay in the literature and Sakai specifically questioned a record from there”. This may be a consequence of Sakai’s (1976: 62) comment that “The localities formerly recorded for this species, such as Hakodate, Sagami Bay and Suruga Bay are due to error.” Takeda & Ueshima (2006), however, recorded H. japonica from Sagami Bay, although the Hakodate record by Stimpson is possibly doubtful as the record was based only on a dredged chela. That being said, it seems entirely possible that H. japonica can occur in the south of Hokkaido island in northern Japan, and in any case, Hitachi is just off the east coast of Honshu.

REMARKS

As discussed above, the Japanese,Taiwanese and southern Chinese specimens of Heikeopsis japonica that we have examined and are depicted in the literature all have consistently longer and more slender P2 and P3, in contrast to the northern Chinese specimens with the same specific name, which have proportionately shorter and wider P2 and P3. This poses a problem as to whether the northern Chinese specimens belong to a separate taxon.

Before we can deal with this, we have to discuss the status of two other taxa:

1) Neodorippe (Neodorippe) japonica var. taiwanensis Serène & Rohmimohtarto, 1969 . It was considered a junior subjective synonym of H. japonica by Holthuis & Manning (1990) who

)

mm

(

CW

5 10 15 20 25 30

CL (mm)

had also studied the types. We examined the holotype male (15.8× 16.6 mm, ZRC 1969.2.24.7) and a female paratype (15.8×17.0 mm, ZRC 1069.22.4.8) from Keelung, Taiwan, and they agree very well with the specimens from Japan, as well as extensive material we have from various parts of Taiwan.The G1 of the holotype male has the subdorsal flap relatively short and positioned subparallel to the distal part ( Fig. 18 I-K), in contrast to those of other specimens in which the dorsal flap is longer and positioned obliquely (e.g., Fig. 18 M-O), but this is due to the poor condition of the specimen: the holotype male appears to have freshly moulted when it was caught and preserved, and this easily explains the condition of the G1 (see also Fig. 18 A-D and observation for G1 of Nagasaki specimen of H. japonica above). As such, we are confident they are synonymous.

2) Nobilum arachnoides Manning & Holthuis, 1986 . The species was briefly diagnosed and figured by Manning & Holthuis (1986) but the taxonomy was elaborated on by Holthuis & Manning (1990) who referred it to Heikea . As discussed earlier, H. arachnoides was only separated from H. japonica by the relatively longer and more slender P2 and P3 (P3 merus less than 6.3 times longer than height for H. japonica ; P3 merus of 6.6 to 7.3 times longer than height for H. arachnoides ). Heikeopsis arachnoides was originally established for a single male specimen (the holotype) measuring 15.8 × 16.7 mm with both chelae equal in size ( Holthuis & Manning 1990: 73, fig. 27e; thus not a fully adult specimen) from Japan, Inland Sea, near Kobe, dredged at 15-91 m by the HMS ‘Challenger’ in 1875 ( NHM 84. 44) ( Manning & Holthuis 1986: 364). This specimen had been reported as ’ Dorippe japonica ’ by Miers (1886: 327). Holthuis & Manning (1990: 72) subsequently included two male specimens collected by R. Gordon Smith in the same Inland Sea area, between 15 and 92 m ( NHM 1903.6.7.5, NHM 1903.6.7.10) and listed them as paratypes. This subsequent designation of these two specimens as paratypes is not admissible under the ICZN rules, and they cannot be treated as such ( Guinot 2023: 240). Examination of the three specimens (one holotype and two topotypes, not paratypes) by Holthuis & Manning (1990, as Heikea arachnoides ) show that, while the P2 and P3 are more elongate (P3 merus is about 7.0 times longer than broad) ( Fig. 3 H-J) than typical material of H. japonica from Japan, the difference is not significant. Holthuis & Manning (1990: 73) also noted that the “Second and third legs […] each reaching beyond front with about half of merus”, but the photograph of the holotype has the proximal half of the P2 and P3 meri not reaching the level of the front when stretched anteriorly.We have a good series of specimens from OMNH that were collected from near the type locality of H. arachnoides (within c. 30 km), and the proportions vary, with the length to width ratio ranging from 5.04 to 6.95 (mean 5.97, n = 72) in P3 and 4.42 to 6.35 (mean 5.40, n = 76) in P2 ( Figs 12 ; 13 ; 15 ). Ng & Huang (1997: 267, figs 3F, 4B) reported H. japonica from Taiwan, but they also noted there was one male specimen (21.3× 23.7 mm, ZRC 1997.0392) that had relatively longer P2 and P3 and as such, they referred it to H. arachnoides ( Ng & Huang 1997: 267, figs 3E, 4A). Ng & Huang (1997) commented that the two species were very similar and observed that the G1 of H. arachnoides had the distal flap slightly longer than the subdistal process compared to H. japonica .

3

conditions palm 2

right

Male

1 16 17 18 19 20 21

22 23 24 25 26 27 28

CL (mm)

Chen & Sun (2002: figs 94, 93, respectively) also recognised two species, Heikea japonica and H. arachnoides , distinguishing them by the length of their legs. Their prognosis was based on the same male specimen (21.3 × 23.7 mm, ZRC 1997.0392) from Taiwan reported by Ng & Huang (1997), compared to 59 males and 40 females of Chinese H. japonica ; Chen & Sun (2002) did not have any other material of H. arachnoides .

Wong et al. (2021) recently reported both taxa in Hong Kong: Heikeopsis arachnoides along Tolo Channel and H. japonica in more western waters, noting that the two species differed in the length of their ambulatory legs: H. arachnoides with longer meri, notably P3 meri 6.6 to 7.3 times longer than high; and H. japonica with shorter P3 meri, less than 6.3 times longer than high ( Wong et al. 2021: 10, fig. 11, pl. 2E and fig. 12, pl. 2F, respectively). We have examined their material, and we are of the opinion both are conspecific. The specimens with proportionately longer P2 and P3 are invariably smaller in carapace size (21.3× 22.0 mm) ( Figs 13 A-C; 15) while those that are larger (carapace size 23.7× 26.2 mm) have relatively shorter legs ( Figs 12 ; 13 D-F; 15). There are no other notable morphological differences.

While we believe that some Japanese specimens with more slender and elongate P2 and P3 represent the extreme end of the observed variation for H. japonica (especially smaller specimens and juveniles) (e.g., Fig. 13 A-C), we have found many individuals which have lost their legs in the OMNH material. This is not expected if the specimens had been trawled and fixed in formalin with other catches.We do not know how dorippids regenerate lost legs, but in examination of a large number of individuals we have found neither bud-like regenerating legs (as seen in grapsoids, for example) nor distinctly shorter legs on the other side. Some asymmetry has been observed, but differences are always subtle (a few millimetres at most). In all the material studied, we found a few cases of leg asymmetry, but we do not know what to attribute them to.

The study of the large series of specimens of Heikeopsis japonica from throughout Japan, Taiwan, southern China, Hong Kong and Vietnam shows that they are all the same taxon. The proportions of the legs of these specimens varies from 4.42 to 6.35 (mean 5.40, n = 76) in P2 and from 5.04 to 6.95 (mean 5.97, n = 72) in P3 ( Fig. 15 ), with smaller specimens often possessing a relatively longer P2 and P3. But there are also some larger adult specimens with slightly longer legs (e.g., from Taiwan, 21.3 × 23.7 mm, ZRC 1997.0392) ( Figs 4E ; 15 ). It is important to note that the three male specimens (including the holotype) studied by Holthuis & Manning (1990) of an intermediate size, being adult but not fully mature, have the male chelae slender and still not inflated ( Fig. 3 H-J).

Holthuis & Manning (1990: 74) suggested that H. arachnoides may prefer deeper waters the original specimens having been collected between 15 and 92 m, and suggested some older records may be this species, e.g., those by Yokoya (1933) and Horikoshi et al. (1982: 126, as Tosa Bay) from east of Owashi, on the east coast of Kii Peninsula, at 132 m, and Sakai (1937) from Korea at 130 m. In any case, in view of the present synonymy of H. arachnoides with H. japonica , this point is moot. There is also the issue of whether some of the old records, e.g., Sakai’s (1937) specimen from Korea may be the short-legged form (see discussion later).

We must now address the question of the short-legged Heikeopsis from North China. The first probable mention of “ Heikeopsis japonica ” from China may be Fauvel (1880) who, in ‘Promenades d’un naturaliste’ on an island (Ningbo) of the Zhoushan Archipelago (also written as Chusan, which today includes many islands in the Ningbo area of northern China), described a ‘very curious crab’ with a carapace length measuring approximately 3 cm, and with P2 and P3 measuring respectively 6 and 7 cm in total length, i.e., in the case of P2, twice the length of the carapace.

As has been discussed earlier, the distribution of the short-legged and typical more long-legged morphs of Heikeopsis japonica in China is compounded by the fact that both are present there, and is complicated by the fact that all adults from northern China are of the former type ( Fig. 15 ). The majority of the Japanese, Taiwanese and southern Chinese (including Hong Kong) are the typical long-legged H. japonica ( Figs 3 ; 4 A-C, E, G-J; 5A, B, E, F; 12A, C-F; 13AC, F) with only a few with relatively shorter legs ( Figs 4D, F ; 5C, D ; 12B ; 13D, E ), and there a few specimens with intermediate proportions (e.g., Figs 12D ; 13F ). Adults from northern China (north of Shanghai to Qingdao) on the other hand are all belonging to the short-legged morph ( Figs 6 ; 14 A-D). The specimen of H. japonica figured by Shen (1931: 101, pl. 6, figs 1, 2) from Hong Kong has relatively longer P2 and P3, and so they belong to the typical long-legged morph of H. japonica as now understood, and we have specimens to confirm this. The specimens of H. japonica from North China ( Shen 1932: 11, figs 6, 7a-e), on the other hand, have clearly shorter P2 and P3 meri, and belong to the short-legged morph. Chinese records without figures by Shen (1937a: 169, 171; 1937b: 305; 1948: 105) from North China are likely the short-legged morph, while those by Shen (1940a: 213) from Hong Kong and by Shen (1940b: 70, 76 (as Dorippe histrio ) from South China belong to typical H. japonica .

Dai et al. (1986), Dai & S. L. Yang (1991: pl. 5, fig. 6) and Chen & Sun (2002) had material from throughout China. This is also true for Japan as Sakai (1937, 1976) who included Korean material as well in their interpretation

35 8

of the species (see later). The same is true for Holthuis & Manning’s (1990) records of Heikeopsis japonica as they included in this species short- and long-legged morphs from Japan and China. Chen (1986: 123, fig. 5.23-27, as Nobilum japonicum ) reported 65 males and 54 females of the species noting (in Chinese) that it inhabits Chinese seas, on substrates of mud and sand from the intertidal zone to depths of 130 m; her figures do not depict the ambulatory legs, so we do not know their condition. Dai & S. L. Yang (1991: pl. 5, fig. 6) depict a H. japonica from China seas with very long and thin legs, but they did not specify where it was from.

On the basis of the geography and the specimens we have examined, we can be fairly certain that Fauvel’s (1880) crab from near Ningbo in northern China is the short-legged morph of H. japonica .

0.04

FIG. 20. — Phylogenetic tree obtained from the mitochondrial 16S rRNA marker by Bayesian Inference. Numbers above branches represent Bayesian posterior probabilities, numbers under branches are Maximum Likelihood bootstrap values. Newly produced sequences are in black, sequences retrieved from GenBank are in grey. Sequences of Heikeopsis japonica as defined by the species delimitation analysis (see Fig. 21 ) are highlighted by the grey box.

We are less certain about the population from Korea as we have only two specimens. The material of Kamita (1934: fig. 1; 1941a: fig. 6; see also Kamita 1935: 62, no figure, all as Dorippe japonica ) and Ko & Lee (2013: 19, figs 10, 11) from Korea appear to have relatively shorter P2 and P3 and are closer to the condition of the short-legged form. Kim (1973: 610, pl. 76, fig. 57a, b; figs 85, 87, as Neodorippe (Neodorippe) japonica ), however, figured the species from Korea, and his photograph of the overall adult habitus (pl. 76, fig. 57a, b) appears to show relatively longer P2 and P3. This is also the case for the specimens we have examined from Korea ( Fig. 6G, H ). All the specimens on hand (including the one figured in Kim 1973) appear to be relatively small (less than 17 mm in carapace length), with none possessing the swollen major chela of large males, and we do know that subadults have relatively longer legs in typical H. japonica (e.g., Fig. 14C, D ). On the basis of these observations at least, we believe Korea has the short-legged morph, which is not surprising as the country is just adjacent to northern China. On this basis, populations from the Yellow Sea ( Kamita 1934, 1935, 1936), Korea Strait ( Kamita 1936), Jinsen (= Incheon) ( Urita 1926), Zinsen ( Sakai 1937), Wido Island ( Kim 1970, 1973), Busan, Jinhae, Masan, Asan, Juan, Hancheon, Nanseo, Myeon and Suun Island ( Kamita 1941b), Soare [in Incheon], Biin and Gomso [in Gyeonggi] in South Korea ( Kim & Kim 1982) probably also belong to the short-legged morph.

MOLECULAR APPROACH

Both 16S and COI were sequenced but 16S had a higher PCR success rate and thus gave the largest dataset to use for this analysis, which is why we only included this marker in our study. The analysis of the 16S rRNA fragment (Fig. 20) revealed that all the sequences from specimens of Heikeopsis cluster in a well-supported clade ( PP = 0.98; B = 84) together with the sequence from Nobilum histrio . Furthermore, the ASAP species delimitation analysis ( Fig. 21 ) supported the hypothesis that all of these sequences are conspecific in all but one of the 10 partition schemes tested.

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ZOOSYSTEMA • 2024 • 46 (31)

Figures

FIG. 1. — Heikeopsis japonica (von Sieibold, 1824), typical morph: A, Colour print by Utagawa Kuniyoshi in 1851: closeup of the ‘Heike-gani’ or ‘samurai crab’, during the naval battle at Dan-no-ura (1185) in Japan’s Inland Sea; B, after De Haan (1839: pl. 31, fig. 1); C, ♂ 23.9× 27.5 mm, Tashi, Ilan,Taiwan,coll. J.-F. Huang, NTOU 8910-06-37 [not examined] [photograph courtesy of J.-F. Huang]; D, ♂, Tashi, Ilan, Taiwan, coll. T-Y.Chan [specimen not preserved; photograph courtesy T.-Y. Chan].

FIG. 2. — Heikeopsis japonica (von Siebold, 1824), short-legged morph, colour in life:A, B, ♂ 21.9 ×24.0 mm, Qingdao, northern China, ZRC 2002.491; C, D, ovigerous ♀ 22.2×24.1 mm, ZRC 2002.0491), Qingdao, northern China; E, F, ♂ 19.8×20.2 mm, ZRC 2023.0044, Qingdao, northern China; G, H, ovigerous ♀ 20.9 ×22.8 mm, Qingdao, northern China, ZRC 2023.0044. A, C, E, G, overall dorsal habitus; B, carapace; D, F, H, ventral surface of cephalothorax. E-H, photograph courtesy of X.Z. Li.

FIG. 3. — Heikeopsis japonica (von Siebold, 1824), typical morph, overall dorsal habitus: A, lectotype ♂ 26.0× 27.4 mm), Japan, RMNH.CRUST.D.822; B, ♀ 16.8 × 18.6 mm, Japan, MNHN-IU-2000-34; C, ♀ 23.5 × 26.7 mm, Japan, MNHN-IU-2000-4091; D, ♂ 22.6 × 24.0 mm, Kyushu, Japan, ZLKU 9425); E, ♂ 25.0 ×27.3 mm, Japan, MNHN-IU-2000-4091; F, ♂ 21.3 ×23.7 mm, Nagasaki, Japan, ZRC 1969.5.5.1; G, ♂ 24.2× 25.6 mm Tokushima, Japan, SMF 57854; H, ♂ 15.2 ×15.7 mm, Inland Sea, Japan, NHM 1903.6.7.5; I, ♂ 12.2 ×12.5 mm, Inland Sea, Japan, NHM 1903.6.7.10; J, ♂ 16.4 × 16.9 mm (holotype male of Nobilum arachnoides Manning & Holthuis, 1986), Inland Sea, Japan, NHM 84.44.

FIG. 4. — Heikeopsis japonica (von Siebold, 1824), typical morph, overall dorsal habitus: A, ♂ 15.8 ×16.6 mm (holotype of Neodorippe (Neodorippe) japonica var. taiwanensis Serène & Romimohtarto,1969),Taiwan,ZRC 1969.2.24.7;B, ♀ 15.8× 17.0 mm (paratype of Neodorippe (Neodorippe) japonica var.taiwanensis Serène & Romimohtarto,1969,Taiwan,ZRC 1969.2.24.8; C, ♂ 20.4 ×22.1 mm, Taiwan,ZRC 1997.622; D, ♀ 21.1× 24.2 mm, Taiwan, ZRC 1997.0622; E, ♂ 21.3 × 23.7 mm, Taiwan;ZRC 1997.0392;F, ♂ 22.0× 23.2 mm,Taiwan,ZRC 1995.0611;G, ♂ 25.3 ×23.5 mm, Taiwan, ZRC 2001.13;H, ♂ 21.4 ×22.5 mm, Taiwan,ZRC 2004.0636; I, ♂ 20.3 × 20.9 mm, Guangdong, southern China, ZRC 1999.0469; J, ♂ 13.1 ×13.3 mm, Guangdong, southern China, ZRC 1999.0467.

FIG. 5. — Heikeopsis japonica (von Siebold, 1824), typical morph, overall dorsal habitus: A, ♂ 21.3 ×22.0 mm, Hong Kong, southern China, ZRC 2021.745; B, ♂ 17.0× 17.5 mm, Hong Kong, southern China, ZRC 2021.746;C, ♂ 20.8 × 22.1 mm,Hong Kong, southern China,ZRC 2021.744; D, ♂ 22.6 ×23.8 mm, Hong Kong, southern China, ZRC 2021.744; E, 20.3× 20.6 mm, Hong Kong, southern China, ZRC 2021.748; F, ♂ 18.4 ×19.4 mm, Vietnam, ZRC 1969.12.18.1.

FIG. 6. — Heikeopsis japonica (von Siebold, 1824), short-legged morph, overall dorsal habitus: A, ♂ 21.9 ×24.0 mm, Qingdao, northern China, ZRC 2002.0491; B, ♀ 23.4 ×26.4 mm, Qingdao, northern China, ZRC 2002.0491; C, ♂ 18.8× 19.0 mm, Shanghai, northern China, ZRC 1998.330; D, ♂ 18.7× 18.9 mm, Shanghai, northern China, ZRC 1998.0330; E, ♂ 29.3 ×31 mm, northern China, MNHN-IU-2018-5197; F, ♀ 24.0 ×26.6 mm, northern China, MNHN-IU-2018-5197; G, ♂ 15.7 × 16.2 mm, Korea, SNUC 271101#005; H, ♂ 16.9× 17.1 mm, Korea, SNUC 271101#006.

FIG. 7. — Heikeopsis japonica (von Siebold,1824),typical morph, carapace:A, lectotype ♂ 26.0× 27.4 mm,Japan, RMNH D-822;B, ♂ 15.8 ×16.7 mm (holotype ♂ of Nobilum arachnoides Manning & Holthuis,1986); Inland Sea, Japan,NHM 84.44; C, ♂ 21.3 ×23.7 mm, Nagasaki,Japan, ZRC 1969.5.5.1;D, ♂ 25.0 × 27.0 mm, Japan, MNHN-IU-2000-4091; E, ♂ 15.8×16.6 mm (holotype of Neodorippe (Neodorippe) japonica var. taiwanensis Serène & Romimohtarto, 1969), Taiwan, ZRC 1969.2.24.7; F, ♂ 23.5× 25.3 mm, Taiwan, ZRC 2001.13; G, ♀ 21.6× 23.1 mm, Taiwan, ZRC 2001.13; H, ♂ 21.4× 22.5 mm, Taiwan, ZRC 2004.636; I, ♂ 20.3× 20.9 mm, Guangdong, China, ZRC 1999.469; J, ♂ 13.1 ×13.3 mm, Guangdong, China, ZRC 1999.467; K, ♂ 21.3 ×22.0 mm, Hong Kong, southern China, ZRC 2021.745; L, ♂ 18.4 ×19.4 mm, Vietnam, ZRC 1969.12.18.1.

FIG. 8. — Heikeopsis japonica (von Siebold, 1824), shorter-legged morph, carapace: A, ♂ 21.9 × 24.0 mm, Qingdao, northern China, ZRC 2002.491; B, ♂ 19.3 ×19.4 mm,Qingdao,northern China,ZRC 2002.491;C, ♂ 18.8 ×19.0 mm,Shanghai,northern China,ZRC 1998.330;D, ♂ 18.7 ×18.9 mm,Shanghai,northern China, ZRC 1998.330; E, ♂ 29.3× 31 mm, northern China MNHN-IU-2018-5197; F, ♀ 23.4 × 26.4 mm, Qingdao, northern China, ZRC 2002.491; G, ovigerous ♀ 24.3×26.7 mm,Jiangsu Province,northern China,ZRC 2023.0045;H, ♂ 15.7×16.2 mm,Korea,SNUC 271101#005;I, ♂ 16.9×17.1 mm,Korea,SNUC 271101#006.

FIG. 9. — Carapace proportions between sexes of Heikeopsis japonica (von Siebold, 1824). Females have slightly wider carapaces. Carapace width (CW) is highly correlated with carapace lenght (CL) in Japanese population.

FIG. 10. — Heikeopsis japonica (von Siebold, 1824), major ♂ chela: A-E, typical morph; F-H, short-legged morph: A, lectotype 26.0 × 27.4 mm, Japan, RMNH. CRUST.D.822; B, ♂ 15.8× 16.6 mm (holotype of Neodorippe (Neodorippe) japonica var. taiwanensis Serène & Romimohtarto, 1969), Taiwan, ZRC 1969.2.24.7; C, ♂ 20.4× 22.1mm, Taiwan,ZRC 1997.622; D, ♂ 22.0 ×23.2 mm,Taiwan,ZRC 1995.611; E, ♂ 23.5 × 25.3 mm, Taiwan, ZRC 2001.13; F, ♂ 21.9 ×24.0 mm,Qingdao, northern China, ZRC 2002.491; G, ♂ 19.3 × 19.4 mm, Qingdao, northern China ZRC 2002.491; H, ♂ 29.3 × 31 mm, northern China, MNHN-IU-2018-5197.

FIG. 11. — Male chelal asymmetry in the Japanese population of Heikeopsis japonica (von Siebold,1824).Male right palm condition is separated into three groups as in the graph below.1, right palm symmetrical with left palm; 2, right palm not fully grown and larger than left palm; 3, right palm fully grown and distinctly larger than left palm. The male right palm becomes fully-grown around CL 23.4 mm CW 23.9 mm (with an exception), which is slightly larger than northern Chinese population (fully grown in 21.9× 24.0 mm (Qingdao, ZRC 2002.0491) and 18.0 ×19.5 mm (Shen, 1932)). This may suggest that Japanese individuals grow larger than northern Chinese individuals, which may affect comparison of their carapace proportions.

FIG. 12. — Heikeopsis japonica (von Siebold, 1824), typical morph, P2-P5: A, lectotype ♂ 26.0× 27.4 mm, Japan, RMNH.CRUST.D.822; B, ♂ 21.3 × 23.7 mm, Nagasaki, ZRC 1969.5.5.1; C, ♂ 15.8 ×16.6 mm (holotype of Neodorippe (Neodorippe) japonica var. taiwanensis Serène & Romimohtarto, 1969), Taiwan, ZRC 1969.2.24.7; D, 21.4 × 22.5 mm, Taiwan, ZRC 2004.636; E, ♂ 21.3 ×23.7 mm, Taiwan, ZRC 1997.392; F, ♂ 18.4× 19.4 mm, Vietnam ZRC 1969.12.18.1. [Legs of each species shot to the same magnification].

FIG. 13. — Heikeopsis japonica (von Siebold, 1824), typical morph, P2-P5: A, ♂ 13.1× 13.3 mm, Guangdong, ZRC 1999.0467; B, ♂ 21.3 ×22.0 mm, Hong Kong, southern China, ZRC 2021.745 (laterally inverted); C, ♂ 17.0 ×17.5 mm, Hong Kong, southern China, ZRC 2021.0746 (laterally inverted); D, ♂ 20.8× 22.1 mm, Hong Kong,southern China,ZRC 2021.0744;E, ♂ 22.6 ×23.8 mm,Hong Kong,southern China,ZRC 2021.744;F, ♂ 20.3× 20.6 mm,Hong Kong,southern China, ZRC 2021.0748. [Legs of each species shot to the same magnification].

FIG. 14. — Heikeopsis japonica (von Siebold,1824),short-legged morph,P2-P5:A, ♂ 21.9×24.0 mm,Qingdao,northern China,ZRC 2002.0491;B, ♂ 19.3×19.4 mm, Qingdao, northern China, ZRC 2002.0491; C, ♂ 15.7 ×16.2 mm, Korea, SNUC 271101#005; D, ♂ 16.9 ×17.1 mm, Korea SNUC 271101#006. [P2 and P3 for C; P4 and P5 for D, laterally transposed]. [Legs of each species shot to the same magnification].

FIG. 15. — Heikeopsis japonica (von Siebold, 1824): relationships between P2 and P3 meri length and length to width ratios against carapace length.

FIG. 16. — Heikeopsis japonica (von Siebold,1824),typical morph,male pleon:A, B, lectotype ♂ 26.0 ×27.4 mm,Japan,RMNH.CRUST.D.822;C, D, ♂ 21.3 ×23.7 mm, Nagasaki,ZRC 1969.5.5.1;E, F, ♂ 25.0× 27.3 mm, Japan,MNHN-IU-2000-4091; G, H, ♂ 23.5× 25.3 mm,Taiwan,ZRC 2001.13;I, J, ♂ 21.3×23.7 mm,Taiwan,ZRC 1997.392;K, L, ♂ 21.4×22.5 mm,Taiwan,ZRC 2004.636;M, N, ♂ 20.4× 22.1 mm,Taiwan,ZRC 1997.622;O, P, ♂ 13.1 ×13.3 mm,Guangdong,China,ZRC 1999.467; Q, R, ♂ 18.4×19.4 mm, Vietnam, ZRC 1969.12.18.1. Male pleonal somites 3-6 and telson (A, C, E, G, I, K, M, O, Q); pleonal somite 1 (B, D, E, H, J, L, N, P, R).

FIG. 17. — Heikeopsis japonica (von Siebold, 1824), short-legged morph, male pleon: A, B, ♂ 21.9 ×24.0 mm, Qingdao, northern China, ZRC 2002.491; C, D, ♂ 19.3 ×19.4 mm, Qingdao, northern China, ZRC 2002.491; E, F, ♂ 18.8 ×19.0 mm, Shanghai, northern China, ZRC 1998.330; G, H, ♂ 29.0 × 30.3 mm, northern China,MNHN-IU-2018-5197; I, J, ♂ 15.7 ×16.2 mm, Korea SNUC 271101#005; K, L, ♂ 16.9 ×17.1 mm, Korea,SNUC 271101#006. A, C, E, G, I, K, male pleonal somites 3-6 and telson; B, D, E, H, J, L, pleonal somite 1.

FIG. 18. — Heikeopsis japonica (von Siebold, 1824), typical morph, gonopods: A-K, ♂ 21.3 × 23.7 mm, Nagasaki,Japan,ZRC 1969.5.5.1; F-H, ♂ 22.6 ×24.0 mm, Kyushu, Japan, ZLKU 9425; I-L, ♂ 15.8×16.6 mm (holotype of Neodorippe (Neodorippe) japonica var. taiwanensis Serène & Romimohtarto, 1969), Taiwan, ZRC 1969.2.24.7;M-P, ♂ 20.4× 22.1 mm,Taiwan,ZRC 1997.0622;Q-T, ♂ 13.1× 13.3 mm,Guangdong,southern China, ZRC 1999.0467;U-X, ♂ 20.3 × 20.9 mm, Guangdong,southern China,ZRC 1999.0469.A, I, M, Q, U, left G1; B, F, right G1 (ventral view);C, J, N, R, V, distal part of left G1 (ventral view);D, K, O, S, W, distal part of left G1 (dorsal view); G, distal part of right G1 (ventral view); E, L, P, T, X, left G2; H, right G2. Scale bars: A, B, E, F, H, I, L, M, P, Q, T, U, X, 1.0 mm; C, D, G, J, K, N, O, R, S, V, W, 0.5 mm.

FIG. 19. — Heikeopsis japonica (von Siebold, 1824), gonopods: A-G, typical morph; H-Q, short-legged morph. A-C, ♂ 20.8 × 22.1 mm, Hong Kong, southern China,ZRC 2021.0744; D-G, ♂ 20.3 ×20.6 mm,Hong Kong, southern China,ZRC 2021.0748; H-J, ♂ 18.8× 19.0 mm, Shanghai,northern China, ZRC 1998.0330; K-N, ♂ 21.9 ×24.0 mm, Qingdao, northern China, ZRC 2002.0491; O-Q, ♂ 15.7 × 16.2 mm, Korea, SNUC 271101#005. A, D, H, K, O, left G1 (ventral view); B, E, I, L, P, distal part of left G1 (ventral view); C, E, J, M, Q, distal part of left G1 (dorsal view); G, distal part of right G1 (ventral view); N, left G2. Scale bars: A, D, H, K, N, O, 1.0 mm; B, C, E-G, I, J, L, M, P, Q, 0.5 mm.

FIG. 21. — Partitions obtained from the ASAP species delimitation analysis on the 16S dataset. Different colours indicate different species according to each