Scopimera sheni Wong, Shih & Chan, 2011, sp. nov.
Creators: name: Wong, Kingsley J. H.
name: Shih, Hsi-Te
name: Chan, Benny K. K.
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Dotillidae
Scopimera
Scopimera sheni

description: Scopimera sheni sp. nov.
(Figs. 1 a–e, 2a–b, 3a–b, 4)
Material examined. HOLOTYPE: 3 (IOASQ-MBM-188711), 36°26' 18.565N 120°43' 44.186E, “Tai Hu Bay”, Qingdao, China, 19 Jun 2010, coll. H.-T. Shih. PARATYPES: 131Ƥ (IOASQ-MBM-188712), data same as holotype; 132ƤƤ (NMNS-6496-001), data same as holotype; 132ƤƤ (ZRC 2010.0367), data same as holotype; 23 2ƤƤ (NCHUZOOL 13385), data same as holotype; 53 6ƤƤ (CEL-Sco-Qingdao-003), data same as holotype.
Comparative material. Scopimera globosa: 39 individuals (ZRC 2002.0498), Qingdao, China, 22 Aug 2002, coll. P.K.L. Ng & H.-L. Chen; 103 2ƤƤ (CEL-Sco-Japan-001), Wakayama, Japan, 7 Aug 2008, coll. B.K.K. Chan; 93 9ƤƤ (CEL-Sco-Qingdao-001), Yellow Island (= Huangdao), Qingdao, China, Jun 2010, coll. B.K.K. Chan.
Diagnosis. Carapace globular, broader than long, surface generally smooth (Figs. 1 a, 4); external maxilliped merus slightly smaller than ischium, joint oblique (Fig. 1 b); molar along cutting edge of cheliped dactylus absent (Fig. 1 c). G1 slender, distal end bent conspicuously into right angle, densely covered by brush of long setae (Fig. 2 a–d).
Description. Carapace thick, globular, broader than long, surface generally smooth except for sparsely spaced, rounded tubercles on expanded branchial regions, faintly along lateral margin of front near base of orbits; regions faintly defined (Figs. 1 a, 4). External orbital angle triangular, pointed; notch behind external orbital angle comparatively obtuse, followed by posteriorly diverging ridges on both sides, extending approximately 2/3 of carapace length, fringed with soft, plumose setae (Fig. 1 a). Sub-orbital ridge lined with about 20 rounded, equal-sized granules, pterygostomian region densely covered with granules of same size. External maxillipeds bulging, merus slightly smaller than ischium, joint oblique; surface generally smooth except for rounded granules along groove running along upper external margin of merus (Fig. 1 b).
Chelipeds roughly equal in size, covered with rounded, flattened granules; merus triangular in cross-section, with single longitudinal tympanum each on internal, external surfaces, upper margin sparsely fringed with darkcolored bristles; carpus elongated, rhomboidal; palm as long as fingers; fingers compressed, tapering into pointed tips, soft, dark-colored bristles lined along weak median ridge on outer surface of fingers, internal edges weakly serrated, tooth along inner margin of dactylus very inconspicuous or absent (Fig. 1 c).
Ambulatory legs slender; first, second longest, subequal in length, fourth shortest; meri extremely compressed, single tympanum occupying most of the segment; propodi, respective dactyli similar in length; dactyli taper to sharp tips, first to third curved inwards, fourth outwards (Fig. 4). Dark bristles along both margins of ambulatory meri, carpi, propodi, dactyli, denser along margins of meri, carpi, propodi of first to third (Fig. 4).
Male abdomen slender, elongated; telson semi-circular, slightly broader than long; sixth somite longer than broad, distal margin slightly broader; fifth somite longer than broad, base constricted, proximal margin concavely rounded; fourth somite much broader than long (Fig. 1 d). Female abdomen broad, circular; telson as small semicircle, somites 6–3 broad, fifth broadest (Fig. 1 e). Male G1 slender, recurved upwards (Fig. 2 a), tapering to fine tip, distal portion conspicuously bent inwards and slightly upwards almost at right angle, upper and outer margin lined with brush of light-colored setae, longer along distal portion and around opening (Fig. 2 a–d).
Size. CW 7.6 mm, CL 6.0 mm for the holotype male (Fig. 4).
Coloration. In general yellowish gray when alive, carapace mottled with cream blots; thoracic somites whitish; cheliped carpi somewhat yellow, chelae whitish; ambulatory legs faintly decorated with brownish bands (Fig. 3 a–b). Dark patch on external maxilliped meri also visible after at least 2 months of alcohol preservation.
Habitat. Burrows in the middle intertidal zone of open sandy flats.
Distribution. So far known only from the type locality (but see “Remarks” below).
Etymology. The new species is named after the late Dr. Jia-Rui Shen (Chia-Jui Shen), for his remarkable pioneering studies of the brachyuran fauna of China. His life-long contribution to crustacean taxonomy was undertaken during the most politically turbulent era of modern Chinese history (Dai 1997). The specific epithet is used as a noun in the genitive case.
Remarks. Scopimera sheni sp. nov. most closely resembles S. globosa, which is also present in North China. The two can be different carapace ornamentation, with the surface of S. sheni sp. nov. being smooth (more apparent in preserved specimens; Fig. 4) whereas that of S. globosa being covered with tubercles (Fig. 1 a, f). The G1 is also clearly different from that of S. globosa: that of S. globosa tapers to a fine tip, the distal end is not bent, and the setae forming the brush on the inner surface are of similar length (see Shen 1932: text-fig. 157b; Sakai 1939: textfig 106b; Dai & Yang 1991: fig. 253(2); Wong et al. 2010: fig. 3a–c). In S. sheni sp. nov., the G1 is bent inward almost at a right-angle, and bears a dense brush of setae on the outer surface (Fig. 2 a–d).
The brachyuran fauna of North China was extensively studied and reviewed by Shen (1932), who reported 3 species: S. globosa, S. bitympana and S. longidactyla. A record of “ S. tuberculata ” was also added to Shen’s (1937) checklist of North China Brachyura, apparently following his recognition of nine male specimens from Peichihli (= Bohai) Bay, and a large number of specimens from South China as “ S. tuberculata ” (see Shen 1935). Shen’s South China “ S. tuberculata ” have subsequently been correctly identified as S. intermedia Balss, 1934 (see Wong et al. 2010); S. tuberculata Stimpson, 1858 was also therein regarded as a subjective junior synonym of S. globosa. Shen’s (1935, 1937) “ S. tuberculata ” material from North China has so far not been found, and therefore its identity is still uncertain
Material examined from Qingdao, also contains specimens of S. globosa, S. bitympana and S. longidactyla; however, none of these three species are endemic to North China: S. globosa is found from Japan to Korea and North China; S. longidactyla from North China, and the coasts of Korea and Taiwan; and S. bitympana from Korea, along the Chinese coast from Shandong to Hainan, and also from Taiwan (Shen 1932; Sakai 1939, 1976; Kamita 1941; Kim 1973; Dai & Yang 1991). Despite examining large Scopimera collections from Japanese waters in NMST and the National History Museum and Institute, Chiba (CBM), Japan, the present S. sheni sp. nov. has not been found, suggesting that it is absent from Japanese shores. Further studies are needed to better define the distribution of S. sheni sp. nov. along the coasts of North China and adjacent regions.
description: Published as part of Wong, Kingsley J. H., Shih, Hsi-Te & Chan, Benny K. K., 2011, Two new species of sand-bubbler crabs, Scopimera, from North China and the Philippines (Crustacea: Decapoda: Dotillidae), pp. 21-35 in Zootaxa 2962 on pages 22-26, DOI: 10.5281/zenodo.207150