HEIKEOPSINAE, Guinot, 2023

Guinot, Danièle, 2023, A new subfamily classification of the highly diversified Dorippidae H. Milne Edwards, 1837 (Crustacea, Decapoda, Brachyura, Dorippoidea), using morphological, molecular and palaeotonlogical data, with special emphasis on its unique female reproductive system, Zoosystema 45 (9), pp. 225-372 : 266-273

Subfamily HEIKEOPSINAE n. subfam.

TYPE GENUS. — Heikeopsis Ng, Guinot & Davie, 2008 (replacement name for Heikea Holthuis & Manning, 1990 ; type species by original designation: Dorippe japonica von Siebold, 1824 ). Other included species: Nobilum arachnoides Manning & Holthuis, 1986 .

OTHER INCLUDED GENERA. — Neodorippe Serène & Romimohtarto, 1969 (type species by subsequent designation by ICZN plenary powers: Dorippe callida Fabricius, 1798 ). Other included species: Neodorippe simplex Ng & Rahayu, 2002 . Nobilum Serène & Romimohtarto, 1969 (type species by original designation: Dorippe histrio Nobili, 1903 ), monotypic.

DESCRIPTION

Carapace ( Figs 1 ; 5C, D ; 19A, B, E, F ; 20A, B ; 21A ) Carapace slightly or distinctly longer than wide and appearing elongated ( Neodorippe ), or slightly wider than long ( Heikeopsis , Nobilum ); convex ( Heikeopsis , Nobilum ) or flattened ( Neodorippe ). Dorsal surface moderately or deeply sculptured, with delineated human facies ( Heikeopsis ); smooth and bare ( Heikeopsis , Neodorippe ) or with some tubercles ( Nobilum ). Gastric regions more or less marked; branchial lobes variously developed or absent. Only a few grooves: precervical groove distinct (but shallow, just discernible in Neodorippe simplex ); cervical and branchiocardiac grooves deep. Antero- and posterolateral margins not demarcated, lacking lateral branchial spine. Front consisting of two broad or sharply pointed triangular teeth separated by shallow, rather wide U-shaped emargination, and extending to or reaching slightly or well beyond outer orbital teeth. Inner orbital teeth practically absent, only as low lobes. Orbital fissure closed ( Heikeopsis , Neodorippe ) or open ( Nobilum ). Inner suborbital tooth or lobe far shorter than front. Outer orbital tooth extending to anterior margin of inner orbital lobe, falling far short of front. Exposed pleurite 6 rather narrow, separated from P3 coxa by thick, whitish membrane. Carapace posterior rim not at all extending at all laterally sideways along posterolateral margin and lined posteriorly by narrow strip, thinner medially than laterally, thus slightly concave, in males as in females.

Illustrations: Heikeopsis arachnoides: Holthuis & Manning 1990 : figs 27a-d, 28a, b, as Heikea arachnoides ; Ng & Huang 1997: fig. 3E, as Heikea arachnoides ; Chen & Sun 2002: fig. 93.1, pl. 1.4, as Heikea arachnoides ; Wong et al. 2021: fig. 11a, pl. 2E. Heikeopsis japonica: De Haan 1839 : pl. 31, fig. 1, as Dorippe callida , but with the specific name of japonica in the Index p. 237 (reproduced by Holthuis & Manning 1990: fig. 34); Shen 1932: fig. 6 (reproduced by Holthuis & Manning 1990: fig. 35; by Sin et al. 2009: fig. 3D); Hothuis & Sakai 1970: 116, 309, pl. 8, fig. 3, as Dorippe japonica ; Takeda 1983: 303, fig. p. 121, as Neodorippe japonica ; Chen 1986b: fig. 5.23, as Nobilum japonicum ; Quintana 1987: fig. 20B, as Nobilum japonicum japonicum ; Holthuis & Manning 1990: figs 29a, 30a, b, 31a, b, 33a, as Heikea japonica ; Ng & Huang 1997: fig. 3F, as Heikea japonica ; Chen & Sun 2002: fig. 94.1, as Heikea japonica ; Ng et al. 2017: fig 3a, as Heikea japonicum ; Wong et al. 2021: fig. 12a, pl. 2F; Neodorippe callida: Chen 1986b : fig. 4.17; Holthuis & Manning 1990: figs 39 (reproduced by Sin et al. 2009: fig. 3E), 40, 41a, 42a-c; Chen & Sun 2002: fig. 95.1; Wong et al. 2021: fig. 13a, pl. 3A. Neodorippe simplex: Ng & Rahayu 2002 : figs 1, 2, 3A. Nobilum histrio: Chen 1986b : fig. 4.20; Holthuis & Manning 1990: fig. 43a (reproduced by Sin et al. 2009: fig. 3F); Chen & Sun 2002: fig. 96.1.

Cephalic structures ( Figs 20F ; 21B )

Eyes short and stout, widening distally; cornea ventrolateral. Antennule entirely folded into fossa, except in Nobilum in which distal part of article protrudes from fossa; in Neodorippe callida , antennule and antenna directed forwards. Antenna: 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.

Illustrations: Heikeopsis arachnoides: Holthuis & Manning 1990 : figs 27b-d, 28b, as Heikea arachnoides . Heikeopsis japonica: Quintana 1987 : fig. 20B-b, as Nobilum japonicum japonicum . Neodorippe callida: Holthuis & Manning 1990 : fig. 42b, c. Neodorippe simplex: Ng & Rahayu 2002 : fig. 3B.

Oxystomatous disposition ( Figs 20F ; 21B )

Openings of exhalant channels scarcely ( Heikeopsis spp. ) or not at all ( Neodorippe , Nobilum ) visible in dorsal view.

Pereiopods ( Figs 1 ; 19 ; 20A, B, C, F, G ; 21A, B )

Distinct heterochely in adult males: major chela much inflated, with short fingers; minor chela slender, with very long fingers bearing numerous teeth on cutting edges; dorsal margin of palm and proximal part of dactylus with fringe of hairs; male major chela greatly inflated, smooth, even as polished, with swollen lobe ventrally near base of fixed finger.

Illustrations: Heikeopsis arachnoides: Holthuis & Manning 1990 : figs 27e, 28c, 29b, 30c, as Heikea arachnoides ; Chen & Sun 2002: fig. 93.2, as Heikea arachnoides ; Wong et al. 2021: fig. 11b, pl. 2E. Heikeopsis japonica: Chen 1986b : fig. 5.24, as Nobilum japonicum ; Holthuis & Manning 1990: fig. 33b, c, as Heikea japonica ; Chen & Sun 2002: fig. 94.2, 3, as Heikea japonica ; Wong et al. 2021: fig. 12b, pl. 2E. Neodorippe callida: Holthuis & Manning 1990 : figs 39, 42d; Chen & Sun 2002: fig. 95.2; Wong et al. 2021: fig. 13b. Neodorippe simplex: Ng & Rahayu 2002 : fig. 3D, E. Nobilum histrio: Holthuis & Manning 1990 : fig. 43b; Chen & Sun 2002: fig. 96.2, 3.

P2 and P3 varying from proportionally short and stout to long and slender, P3 longest; articles flattened, unarmed, with fringes of long setae ( Heikeopsis , Neodorippe ) or fringes of short setae ( Nobilum ); upper and lower margins of dactyli with fringe of setae, either long ( Heikeopsis , Neodorippe ) or short ( Nobilum ).

Illustrations: Heikeopsis arachnoides: Holthuis & Manning 1990 : figs 27f, 28d, as Heikea arachnoides ; Chen & Sun 2002: fig. 93.3, as Heikea arachnoides ; Wong et al. 2021: fig. 11c, pl. 2E. Heikeopsis japonica: Holthuis & Manning 1990 : figs 29c, 30d, e, 31c, 33d, as Heikea japonica ; Wong et al. 2021: fig.12c, pl. 2E. Neodorippe callida: Holthuis & Manning 1990 : fig. 42d; Wong et al. 2021: fig. 13c. Neodorippe simplex: Ng & Rahayu 2002 : fig. 3F. Nobilum histrio: Holthuis & Manning 1990 : fig. 43c, d.

P4, P5 reduced ( Chen & Sun 2002: fig. 96.4).

Thoracic sternum ( Figs 19C, D ; 20 C-H; 21B-F)

Thoracic sternum moderately wide.Sternite 1with small portion may be dorsally visible.Sternite 2 salient, with marked external angles; sternite 3 extended, consisting of deep, smooth depression and salient curved margins. Sutures 4/5-7/8 interrupted. Suture 3/4 ending in closed boutonniere. Sternite 7 exposed as long, oblique plate along each side of pleon; suture 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; in females, interrupted and each end linked by sulcus, sometimes membranous. Female thoracic sternum progressively tilted backwards at level of weak ridge of sternite 6 ( Heikeopsis , Nobilum ) or only weakly tilted ( Neodorippe ); in females, sternite 8 (its fused portion) with erect axial spine ( Heikeopsis ),long and recurved ( Neodorippe ), or with tubercule ( Nobilum ).

Illustrations: Heikeopsis japonica: Holthuis & Manning 1990 : fig. 29e, f, as Heikea japonica . Neodorippe callida: Holthuis & Manning 1990 : fig. 41b. Nobilum histrio: Holthuis & Manning 1990 : fig 43h, i.

Pleon and telson ( Figs 19C, D ; 20C, D ; 21C, E, F )

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 ( Heikeopsis ) except in Neodorippe simplex with somites 3-5 fused, immovable but sutures still visible (according to Ng & Rahayu 2002: fig. 3C). Somite 1 trapezoidal, widening posteriorly, with longitudinal groove on either side; somite 2 with wide and blunt transverse ridge or protuberance; somite 3 with two large, blunt lateral swellings and one median less elevated ( Heikeopsis ), or trilobed ( Neodorippe , Nobilum ), lodging bulged protopodite of G1s; somite 4 small, narrowing posteriorly, smooth ( Heikeopsis, Neodoripp e), with tooth-like dorsal elevation in middle ( Nobilum ); somites 5, 6 smooth ( Heikeopsis ) or with elevations ( Nobilum , Neodorippe ); telson triangular, apex rounded, tip of telson not very far from suture 4/5.

Illustrations: Heikeopsis arachnoides: Holthuis & Manning 1990 : figs 27g-i, 28e, f, as Heikea arachnoides ; Chen & Sun 2002: fig. 93.4, as Heikea arachnoides ; Ng et al. 2017. Heikeopsis japonica: Holthuis & Manning 1990 : figs 29c, 30f, 31e, f, as Heikea japonica . Neodorippe callida: Holthuis & Manning 1990 : fig. 42f. Neodorippe s implex Ng & Rahayu 2002: fig. 3C. Nobilum histrio: Holthuis & Manning 1990 : fig. 43e; Chen & Sun 2002: fig. 96.5.

Female pleon with all somites free, somites increasingly broader posteriorly; somites 2-5 smooth, without sharp teeth or spines, each somite crossed by smooth submedian ridge; telson subtriangular to semicircular, tip of telson exceeding level of suture 5/6. (See below, Additional female pleonal-retention mechanism).

Illustrations: Heikeopsis japonica: Holthuis & Manning 1990 : figs 29d, 31d, g, as Heikea japonica . Neodorippe s implex: Ng & Rahayu 2002: 747.

Pleonal locking mechanism by press-button ( Figs 20 E-H; 21D-F)

Locking buttons on posterior margins of sternite 5. Also effective in females as in all dorippids, locking prominences lying very close to vulvae. Despite thickness of egg mass and long pleopodal setae, locking mechanism remaining efficient: for example, firm closing with highly effective buttons and sockets found in ovigerous females of Neodorippe from Australia.

Additional female pleonal-retention mechanism ( Figs 19B, F ; 21E, F )

In females, strong retention by wide process of sternite 8 overhanging pleonal somite 2 in Heikeopsis and Nobilum , whereas only a small non-functional tubercle in Neodorippe callida ( Fig. 20B ), and nothing in N. simplex . In addition, small telson engaged between raised slopes of sterno-pleonal cavity at level of sternite 5.

Male gonopore and penis

Male gonopore coxal.Coxo-sternal condition, the most elaborate of all dorippids and similar to that of ethusids. Sternites 7 and 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; in Heikeopis and Nobilum penial bulb and proximal inclined portion of penis clearly visisible dorsally between sternite 7 and widely exposed sternite 8; similar arrangement but less easy to see in Neodorippe .

Illustrations: Neodorippe callida: Guinot et al. 2013: 104 , fig. 19 (reproduced by Davie et al. 2015a: 41, fig. 72-2.19H).

Gonopods ( Figs 20E ; 21D ; 31 D-F)

G1 without basal lobe; inverted C-shaped (in situ), stout proximally, then slender and elongated, strongly bent and largely curved outward; apex tapering in single process ( Neodorippe simplex ) or more elaborate and ending in rounded lobe plus two sharp unequal distal processes ( N. callida ), or in three short, broad, rounded subequal processes ( Nobilum ), or in two elongate, blunt-toped unequal lobes plus two subdistal processes ( Heikeopsis ).

Illustrations: Heikeopsis arachnoides: Holthuis & Manning 1990 : fig. 28g, h, as Heikea arachnoides ; Dai & Yang 1991: fig. 24.1, as Dorippe (Neodorippe) japonica ; Ng & Huang 1997: fig. 4A, as Heikea arachnoides ; Chen & Sun 2002: fig. 93.5, as Heikea arachnoides . Heikeopsis japonica: Chen 1986b : fig. 5.25-27, as Nobilum japonicum ; Holthuis & Manning 1990: figs 32, 33e-g (reproduced by Sin et al. 2009: fig. 4D; by Davie et al. 2015a: fig. 71- 2.31E), as Heikea japonica ; Ng & Huang 1997: fig. 4B, as Heikea japonica ; Chen & Sun 2002: fig. 94.4.5, as Heikea japonica ; Vehof 2020: fig. 11A, C, D. Neodorippe callida: Chen 1986b : fig. 4.19; Holthuis & Manning 1990: fig. 42g, h (reproduced by Sin et al. 2009: fig. 4E); Dai & Yang 1991: fig. 24.2, as Dorippe (Neodorippe) callida ; Chen & Sun 2002: fig. 95.3. Neodorippe s implex Ng & Rahayu 2002: fig. 3G-I. Nobilum histrio: Chen 1986b : fig. 4.21, 22; Holthuis & Manning 1990: fig. 43d, g (reproduced by Sin et al. 2009: fig. 4F); Chen & Sun 2002: fig. 96.6.

G2 folded, bent ( Heikeopsis japonica: Vehof 2020 : fig. 11B. Neodorippe simplex: Ng & Rahayu 2002 : fig. 3J); also bent in Nobilum .

Vulvae ( Figs 20 F-H; 21E, F; 32D-F)

In Heikeopsis and Nobilum 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 not entirely exposed or slightly obliquely directed on submedian area of sternite 6. In Neodorippe vulva suboval, shorter, not sunken, completely exposed.

Illustrations: Heikeopsis japonica: Holthuis & Manning 1990 : fig. 29e, f, as Heikea japonica . Neodorippe callida: Holthuis & Manning 1990 : fig. 41b, c; Vehof 2020: fig. 5B, C. Nobilum histrio: Holthuis & Manning 1990 : fig 43h, i; Chen & Sun 2002: fig. 96.6; Vehof 2020: fig. 5D.

Female reproductive system

Studied in Heikeopsis japonica , Neodorippe callida and Nobilum histrio by Vehof (2020: 52, fig. 6) the reproductive system is similar in the species of the three genera. Here, on each side of the body there is a single sperm storage organ, as in Medorippinae n. subfam. ( Figs 35C ; 37 ) and other Eubrachyura. See Figures 35E ; 37 and below, The female reproductive system in Brachyura , its evolution and unique disposition in Dorippidae .

DISTRIBUTION AND HABITAT

Heikeopsis japonica , native to Japan and abundant in the Inland Sea and also in Ariake Bay ( Yokoya 1933, as D. japonica ; Sakai 1937: 72, pl. 10, fig. 1, as D. japonica , material from 130 m; Sakai 1976, as D. japonica ; Horikoshi et al. 1982, as D. japonica ), is thought to inhabit the western Pacific: Korea (it is common on the Yellow Sea side) ( Kim 1973; Koh & Lee 2013; Lee et al. 2021), north to south China ( Shen 1937a, 1937b, as D. japonica ; Dai & Song 1986, as D. japonica ; Dai et al. 1986, as D. japonica ; Dai & Yang 1991, as D. japonica ; Chen & Sun 2002: 222; Wong et al. 2021: 11, fig. 12, pl. 2F), Taiwan ( Ng et al. 2001, as Heikea japonicum ; Ng et al. 2017, as Heikeopsis japonicum ), and Nhatrang, Vietnam ( Serène & Romimohtarto 1969, as Dorippe japonica ). Other records of Heikeopsis japonica are: Doflein 1904: 292, as D. japonica ; Chou et al. 1999, as D. japonica ). But it is likely that two species are confused under the specific name of japonica : the typical Heikeopsis japonica , with rather long and slender P2 and P3, and another form with shorter and stouter P2 and P3, see below, Status of non-Japanese Heikeopsis japonica, H. taiwanensis ( Serène & Romimohtarto, 1969) , and H. arachnoides ( Manning & Holthuis, 1986) : a major problem.

The status of two other Heikeopsis with long and slim legs is also a problem: 1) Neodorippe (Neodorippe) japonica var. taiwanensis established by Serène & Romimohtarto (1969) and whose holotype is preserved in ZRC ( Yang 1979: 3, as Neodorippe (Neodorippe) japonica var. taiwanensis ), but judjed as falling within the range of variation of H. japonica by Holthuis & Manning (1990: 87); 2) Heikeopsis arachnoides , assumed to inhabit only the Inland Sea of Japan according to Holthuis & Manning (1990: 74, as Heikea arachnoides ; see Miers 1886: L, 327, 328, as Dorippe japonica ), but reported from China by Chen & Sun (2002: 220, fig. 94) and from Hong Kong by Wong et al. (2021: 11, fig. 12, pl. 2E), and also recorded from northeastern Taiwan ( Ng & Huang 1997, as Heikea arachnoides ; Ng et al. 2001, as H. arachnoides ; Ng et al. 2017). According to Ng & Huang (1997: 267), “Whether any of the old records also represent H. arachnoides cannot be ascertained”. Holthuis & Manning (1990: 72 and 75, respectively, as Heikea arachnoides and H. japonica ) recognised two species: Heikeopsis arachnoides and H. japonica . See below, Status of non-Japanese Heikeopsis japonica, H. taiwanensis ( Serène & Romimohtarto, 1969) , and H. arachnoides ( Manning & Holthuis, 1986) : a major problem.

Neodorippe callida shows a wide distribution, ranging from Red Sea ( Herklots 1861, as Dorippe astuta ) to Southeast Asia and China and having been also reported from Pakistan, India and Bangladesh ( Alcock 1896, as Dorippe astuta ; Venkataraman et al. 2004, as Dorippe astuta ; Dev Roy 2008; Roy & Nandi 2008; Trivedi et al. 2018: table 1; Akash et al. 2020), the Philippines, Vietnam ( Dai & Song 1986, as Dorippe astuta ), Singapore ( Ng & Tan 1986; Tan & Ng 1988, as Neodorippe (Neodorippe) astuta ); Vietnam ( Do Van Nhuong et al. 2021, as Neodorippe callida ); Malaysia ( Zakirah et al. 2022), western Indonesia, Thailand ( Ng & Davie 2002) and South China ( Chen 1986b; Chen & Sun 2002; Wong et al. 2021). For more references, see Holthuis & Manning (1990: 95-103). The species has been recorded in tide pools and shallow waters at depths from 3.6 to 46 m and is found on mud or sandy mud bottoms, being very common in mangrove swamps ( Serène & Romimohtarto 1969, as Neodorippe (Neodorippe) callida ; Ng 1987, as Neodorippe (Neodorippe) callida ).

Neodorippe simplex is known from the shallow waters of the continental shelf of Irian Jaya and northern Australia ( Ng & Rahayu 2002). The identity of the N. callida from the western continental margin of Australia ( McEnnulty et al. 2011) would be interesting to check.

Nobilum histrio is only known from Malaysian and Singapore waters ( Nobili 1903, as Dorippe histrio ; Serène & Romimohtarto 1969, as Neodorippe (Nobilum) histrio ; Holthuis & Manning 1990: 106), Vietnam ( Dawydoff 1952, as ‘ Doryppe histrix ’), and China ( Chen 1986b; Chen & Sun 2002). Its habitat and biology are not documented.

CARRYING BEHAVIOUR

All species of Heikeopsinae n. subfam. have reduced and subcheliform P4 and P5 but the carrying behaviour is only well documented in Heikeopsis and Neodorippe ; almost nothing is known of the habitat or biology of H. arachnoides (if valid) and Nobilum histrio .

Heikeopsis japonica uses dead shell or other material such a sand dollar and is sometimes associated with a sea anemone or wooden-piece ( Sakai 1937: 73; 1976: 61, as Dorippe japonica ; Holthuis & Manning 1990: 86, as Heikea japonica ) and with sea pens ( Itani & Fujihara 2001). Laboratory experiments showed that both megalopa and first crab stages of H. japonica virtually do not swim and carry fragments of shells or rocks dorsally by using P4 and P5 ( Quintana 1987: 253, figs 8, 10E, F, 12F, G, 24C, as Nobilum japonicum japonicum ).

Species of Neodorippe , which are primarily inhabitants of mangrove area, differ from all other dorippids in having a leaf carrying habit. The association of N. callida , the ‘leaf-porter crab’, with mangrove leaves is very close and not just temporary ( Rathbun 1910; Guinot et al. 1995; Guinot & Wicksten 2015: fig. 71-11.8C). Observations of Neodorippe callida in Singapore ( Ng & Tan 1986: 45-46, fig. 1, table 1, as Neodorippe (Neodorippe) callida ; Ng 1987: 14-15; Tan & Ng 1992: 102 as Neodorippe (Neodorippe) callida ; Lim et al. 1994: 108, 127) point to a unique pattern of behaviour. “Even during the day when the individual is buried in the mud, it holds a leaf; at night, it is a slow but competent swimmer, reversing its orientation with the ventral sternal plate facing the water surface and the leaf downward” ( Ng 1987: 14-15). The P4 and P5 grasp the four different corners of the leaf, the point of articulation between the carpus and propodus being equipped with opposable tufts of hairs providing an excellent hold to grip the leaf with the hooked dactylus (P. K. L. Ng, pers. comm.; see his sketch in Guinot & Wicksten 2015: fig. 71-11.9H, I). In the aquarium, individuals of Neodorippe simplex “carry leaves on their backs and swim upside down, with the leaf, when disturbed” ( Ng & Rahayu 2002: 757, fig. 1). For further references, see Holthuis & Manning (1990: 101-103). The use of seaweeds as camouflage in brachyuran crabs with the legs is not very common, being observed occasionally only in some podotremes (dromiids, cyclodorippids, latreilliids) and eubrachyurans (palicids with their P5). In a completely different way, it is widespread in majoids, which use specialised setae on the body and legs ( Guinot & Wicksten 2015; McLay 2020).

REMARKS

Dorippe japonica , collected in Japan by local fishermen for Ph. F. von Siebold in 1823 and described byvon Siebold (1824: 15, as Doripe [sic] japonica ; 1826: 18; 1850: xiii), was studied and represented by De Haan in Fauna Japonica (1839: pl. 31, fig. 1, as Dorippe callida ; 1841: 122 and in Index p. 227, as Dorippe . japonica ) ( Fig. 1A ). In the collections of pictures of crabs and shrimps (Kai-ka Rui Siya-sin), prepared by the well-known naturalist Kurimoto Suiken (1756-1834) and donated to Von Siebold in 1826, figures 41 and 42 of plate 6 of volume 1 show a long-legged crab (dorsal and ventral views) with two vernacular names: ‘Kimen-gani’, i.e., ogre-faced crab, and ‘Heike-gani’ in reference to the famous Japanese legend that crabs of this species are the spirits of deceased members of the Heike family with human traits engraved on their carapaces ( Figs 2 ; 39 ; Appendix 1). They are accompanied by two mentions: Von Siebold’s name in ink: Dorippe japonica n. sp., and De Haan’s name in pencil: Dorippe japonica F. J., by reference to Fauna Japonica ( Yamaguchi & Holthuis 2001: 30, 31). Von Siebold (1824: 14; 1850: xiii, footnote) and De Haan (1841: 122), who quotes the figures of Suiken, gave Dorippe japonica the vernacular names ‘Heike-gani’, ‘Heike-Kani’ and ‘Feike-Gani’. In fact, ‘Heike-gani’ is the only vernacular name that corresponds with certainty to the Japanese crab of von Siebold and De Haan. Much later, the genus was given the name Heikea by Holthuis & Manning (1990), replaced by Heikeopsis by Ng et al. (2008: 59, 60).

A total of 31 specimens had been collected and deposited at the RMNH (RMNH.CRUS.D.822) (see Fransen et al. 1997: 83, as Heikea japonica ). A lectotype (see Fig. 1B ) and several paralectotypes were designated from the type series by Yamaguchi & Baba (1993: 300, figs 90a.a-1, a-2, b, d-f, 90- B, as Heikea japonica ). The type locality mentioned by Von Siebold (1824) is Shimonoseki, the one in the Fauna Japonica is Nagasaki, but according to Yamaguchi & Baba (1993: 300, as Heikea japonica ) such a locality record is absent from the labels of all the type series material. Holthuis & Manning (1990: 77) considered the provenance to be more likely from “near Nagasaki ”. A dry specimen deposited at the MNHN, MNHN-IU-2000-34 (= MNHN-B34), considered non-type according to Yamaguchi & Baba (1993: fig. 90B.g, as Heikea japonica ), could be part of the type series. Another Japanese sample from the historical collection, with a male and a female in dry condition MNHN-IU-2000-4091 (= MNHN-B4091), probably belongs to the type series ( Fig. 1C ).

Nobilum and Heikeopsis are closely related genera but differ primarily in the G1, with three petaloid lobes in Nobilum , with two subdistal processes and two elongated, unequal distal lobes in Heikea , and by a spine on the orbital margin in Nobilum , absent in Heikea . Note that the G1 of Neodorippe callida ends in two processes, one sharp, one rounded, and that of Neodorippe simplex is simple, with a single tapering process.

In Neodoripp e the elongation and shape of the penis as well as other features, such as the small size and the smooth, flattened and elongated carapace ( Figs 5D ; 20A, B ), are somewhat suggestive of an ethusid, but it is a true dorippid.

Figures

FIG. 1. — A typical dorippid crab, Heikeopsis japonica (von Siebold, 1824), the iconic ‘samurai crab’ known in Japan as ’heike-gani’, whose carapace looks like a human face: A, the species represented by De Haan (1839: pl. 31, fig. 1, as Dorippe japonica) in Fauna Japonica: top, a female; below, chelae of a male; B, lectotype selected by Yamaguchi & Baba (1993: 300, fig. 90-A.a-2, as Heikea japonica) from type series material labelled “Types, Japan, 1823, Leg. P. H. von Siebold”, RMNH CRUS D 822 (see Fransen et al. 1997: 83); C, ♂ 25.0 × 27.3 mm, ♀ 23.5 × 26.7 mm, Japan, Chaffanjon, 174-96, E.-L. Bouvier det. 1899 Dorippe japonica, dry condition, MNHN-IU-2000-4091 (= MNHN-B4091).

FIG. 5. — Terminology of main grooves on dorsal carapace of Dorippidae: A, diagrammatic figure of Holthuis & Manning (1990: fig. 1, based on a Dorippe species) without any mention of ‘precervical groove’. B-D, terminology used in the present paper and only partially used by Holthuis & Manning (1990). B, Dorippe tenuipes Chen, 1980: after Holthuis & Manning (1990: fig. 18a); C, Heikeopsis japonica (von Siebold, 1824): after Holthuis & Manning (1990: fig. 30a, as Heikea japonica); D, Neodorippe callida (Fabricius, 1795): after Holthuis & Manning (1990: fig. 39). The strip, which runs posteriorly along the rim, was only figured in C. Abbreviations: b.c., branchiocardiac groove; c.g., cervical groove; l.b., branchial lobe; p.g., precervical groove; r, rim; s, strip.

FIG. 19. — Heikeopsinae n. subfam. A-D, Heikeopsis japonica (von Siebold, 1824): A, ♂ 22.5 × 24.3 mm, Japan, Tokushima, SMF 57856: habitus; B, ♀ 23.5 × 26.7 mm, Japan, Chaffanjon, MNHN-IU-2000-4091 (= MNHN-B4091): habitus; C, ♂ 25.0 × 27.3 mm, same data as B: ventral view; D, ♂ 24.2 × 25.4 mm, same data as B and C: thoracic sternum and pleon. E, F,?Heikeopsis aff. japonica, China, seas off Qingdao, ZRC 2002.0491: habitus: E, ♂ 21.9 × 24 mm; F, ♀ 23.4 × 26.4 mm.

FIG. 20. — Heikeopsinae n. subfam. Neodorippe callida (Fabricius, 1798): A, young ♂ 10.1 × 10.3 mm, Singapore, Changi Point Beach, ZRC 2018.0445: habitus of young male; B, C, Andaman Sea, Phuket, Thailand, MNHN-IU-2016-10754 (ex ZRC 1998.1116): B, ♀ 14.0 × 15.0 mm, habitus; C, ♂ 13.5 × 14 mm: ventral view. D, E, ♂ 10.1 × 10.3 mm, same data as A, ZRC 2018.0445:D, thoracic sternum with pleon; E, without pleon, G1, press-buttons. F, ♀ 11.2 × 11.5 mm, same data as A, D, E, ZRC 2018.0445: anterior view. G, ♀ 11.2 × 11.5 mm, sama data as B, C, MNHN-IU-2016-10754: vulvae, press-buttons. H, ♀ 11.2 × 11.5 mm, same data as A, D, E, F, ZRC 2018.0445: vulvae.

FIG. 21. — Heikeopsinae n. subfam.Nobilum histrio (Nobili,1903), Malaysia, Johore,Pontian, ZRC 2002.0491:A-D, ♂ 21.0 × 22.4 mm:habitus; B, anterior ventral view; C, thoracic sternum with pleon; D, thoracic sternum without pleon, penis and G1. E, F, ovigerous ♀ 22.1 × 24.7 mm: thoracic sternum, pleon and vulvae.

FIG. 31. — Diversity of G1s in the seven dorippid subfamilies (schematic drawings): A, Dorippinae n. stat. (Dorippe quadridens); B, Dorippoidinae n. subfam. (Dorippoides facchino); C, Medorippinae n. subfam.(Medorippe lanata); D-F, Heikeopsinae n.subfam.:D, Heikeopsis?japonica; E, Neodorippe callida; F, Nobilum histrio; G, Paradorippinae n. subfam. (Paradorippe cathayana); H, Philippidorippinae n. subfam. (Philippidorippe philippinensis); I, Phyllodorippinae n. subfam. (Phyllodorippe armata). (A-H, after Holthuis & Manning 1990; I, after Manning & Holthuis 1981). From Sin et al. (2009: fig. 4). Setae not always figured.

FIG. 35. — Schematic illustrations of female reproductive systems in representatives of four dorippid subfamilies:A, B, Dorippinae n. stat.: A, Dorippe sinica Chen, 1980, as interpreted by Hayer et al. (2016a: fig. 2); B, Dorippe quadridens (Fabricius, 1793) and D. sinica, as interpreted by Vehof et al. (2017: fig. 2A); C, Medorippinae n. subfam.: Medorippe lanata (Linnaeus, 1767), as interpreted by Vehof et al. (2017: fig. 2B); D, Paradorippinae n. subfam.: Paradorippe granulata (De Haan, 1841), as interpreted by Vehof et al. (2018b: fig. 3). E, Heikeopsinae n. subfam.: Heikeopsis japonica (von Siebold, 1824), with the same pattern shared by Neodorippe callida (Fabricius, 1798) and Nobilum histrio (Nobili, 1903), as interpreted by Vehof (2020: fig. 4). Abbreviations: a, apodeme; amb, anteromedian bursa; bu, bursa;cu, cuticle;cv, cuticular valves;bu, bursa; ev, extension of vulva;ge, glandular epithelium; mu, musculature;oc, oocyte; od, oviduct; ov, ovary; plb, posterolateral bursa; sr, seminal receptacle; vg, vagina; v, vulva.

FIG. 37. — Schematic representation of character mapping of sperm storage organs in the different dorippid subfamilies recognised here (except Phyllodorippinae n.subfam.not studied) and in a typical eubrachyuran:ovary with oocytes; oviduct; cuticular bursae (thin black line), of equal or unequal size; seminal receptacle either bilateral twin- or bilateral single,and either completely cuticular (thin black line) or partially glandular (thick black line). The twin system occurs in Dorippinae n. stat., Dorippoidinae n. subfam., Paradorippinae n. subfam. and Philippidorippinae n. subfam.; the single system occurs in Heikeopsinae n. subfam.,Medorippinae n. subfam.and in the typical Eubrachyura (most, see e.g. Ethusidae). Modified from Vehof 2020: figs 20-22).

FIG. 2. — Colour print by Utagawa Kuniyoshi in 1851: The ghost of Taira Tomomori along with the anchor he drowned with, and heikegani with faces of fallen soldiers; A, Heikeopsis japonica (von Siebold, 1824), the ‘heike-gani’ or ‘samurai crab’, during the naval battle at Dan-no-ura (1185) in Japan’s Inland Sea; B, closeup view of the crabs, easily recognisable by their carapaces bearing like a human face, their last two legs, reduced and carried dorsally, and the dorsally visible pleon (See also Fig. 39).

FIG. 39. — The ghost of Taira Tomomori along with the anchor he drowned with, and heikegani with faces of fallen soldiers, colour print by Utagawa Kuniyoshi illustrating the legend of the iconic ‘samurai crab’ known in Japan as ’heike-gani’,a dorippid whose current scientific name is Heikeopsis japonica (von Siebold, 1824).It depicts the naval battle of Dan-no-ura in the Japanese Inland Sea in 1185 between the two clans Heike and Gengi. Members of the Heike clan and generals tie themselves to the anchor of the ship to sink to the bottom of the sea and to rejoin the drowned. The souls of deceased Heike warriors were passed on to the crabs, and their faces were etched forever on the carapaces of the crabs. In Japan, Heike-gani crabs are considered to be the reincarnations of the samurai who died at Dan-no-ura.