Sinopotamon mayangense Naruse, Yeo & Zhou, 2008, spec. nov.
Creators: name: Naruse, Tohru
name: Yeo, Darren C. J.
name: Zhou, Xianmin
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Potamidae
Sinopotamon
Sinopotamon mayangense

description: Sinopotamon mayangense spec. nov.
(Figs. 10–12)
Material examined. Holotype: male, 26.5× 33.4 mm, NCU MCP 2008.0006, Jinjiang River, Xueli Village (ca. 27°49’ 0 1’’N 109°48’ 0 3’’E), Gaocun Rural, Mayang Miao autonomous county, Hu’nan Province, China, coll. Huilin Duan & Xianmin Zhou, 26 Jul. 2005.
Paratypes: 1 male, 21.7× 26.7 mm, 7 females, 21.9×27.4–24.9× 31.5 mm, NCU MCP 2008.0007, data same as holotype; 2 males, 26.9×34.6, 26.9× 33.2 mm, 4 females, 23.8×29.4–28.6× 36.6 mm, ZRC 2008.0015, data same as holotype; 3 males, 22.9×28.0–24.5× 30.2 mm, 2 females, 21.6×28.1, 24.6× 31.4 mm, NMNS- 5752-001, data same as holotype.
Description. Carapace (Fig. 10 a) broader than long, widest across middle of anterolateral margins, CW 1.22–1.30 times (mean 1.26, n = 12) CL; dorsal surface flat, smooth; epigastric, postorbital cristae oblique; cervical, H-shaped gastric grooves shallow, indistinct; anterolateral region with elongated granules. Front gently directed downwards, anterior margin straight, frontal region granulated. Supra-, infraorbital margins (Fig. 10 b) cristate, lined with small granules, only inner part of suborbital region, anterior part of pterygostomial region with granules. External orbital angle directed anterior-inward, outer margin about 3 times longer than inner margin; epibranchital tooth distinct, anterolateral margin convex laterally, granules distinct. Antennular fossa rectangular; epistome with posterior margin cristate, lined with granules, with sharp triangular median tooth.
Palp of mandible three-segmented, with terminal segment simple. Third maxilliped (Figs. 10 b, 11) rectangular, midlength of ischium about 2 times that of merus, exopod reaching proximal two-fifths of outer margin of merus, flagellum long, slightly shorter than width of merus.
Thoracic sternites 2, 3 demarcated by unevenness, suture between sternites 3, 4 indiscernible. Abdominal cavity reaching imaginary line joining posterior quarter of cheliped coxae, cavity relatively wide, distance between inner ends of sutures between thoracic sternites 4, 5 longer than third length of distance between sternal condyles; sternal condyle on slightly below middle of thoracic sternite 5; thoracic sternite 8 demarcated medially by uninterrupted longitudinal median line, without transverse ridge at inner ends of sutures between thoracic sternites 7, 8.
Cheliped (Fig. 10 a) slightly asymmetrical, major cheliped stouter, longer than minor; merus granulated on dorsal, ventral margins; carpus with strong, sharp inner angle, small tooth below angle; palm smooth, height shorter than length; fingers as long as palm, gape narrow when closed, cutting edge lined with low teeth.
Ambulatory legs (Fig. 10 a) moderately long, surfaces rough, anterior margin of meri lined with obtuse low teeth, moderately long, second, third longest when stretched laterally; dactyli as long as respective propodi in P2–P4, slightly shorter in P5.
Abdomen (Fig. 11) with regularly divergent lateral margins, first abdominal segment with transverse ridge; third segment widest; telson with lateral margins concave proximally, width 1.26 times length (n = 1), 1.29 times (n = 1) longer than sixth segment, sixth segment width 2.21 times length (n = 1). G1 (Figs. 12 a, b) stout; proximal outer part of subterminal segment concave; outer ventral layer of subterminal segment with suture along inner margin, distal part of subterminal segment raised ventrally, distodorsal part concave medially, boundary between subterminal, terminal segments membrane-like; distal segment length quarter of total G1 length, strongly bent inwards, opening on subdistal part of anterior surface. G2 (Fig. 12 c) as long as G1, flagellum ribbon-like, about three-fifths length of narrowed part of basal segment.
Distribution and habitat. Sinopotamon mayangense spec. nov. is found from the type locality (Gaocun Rural, Mayang Miao autonomous county, Hu’nan Province, China;> 200m asl.) Hu’nan (mayang) The species was found from under screes in a rivulet.
Remarks. Sinopotamon mayangense spec. nov. is similar to S. bilobatum Dai & Jiang, 1991, and S. nanlingense Dai & Jiang, 1991, in the short, stout and bent distal segment of the G1 of the three species. Sinopotamon mayangense, however, can be distinguished from S. bilobatum by the strong bent (ca. 60°) of the terminal segment of the G1 [vs. blunt and less bent (ca. 45°)], a tapering tip of the terminal segment (vs. bilobate distal tips), and the subdistal opening of the terminal segment (vs. opening distal) [Figs. 12 a, b; Dai & Jiang 1991: Fig. 2 (3, 4); Dai 1999: Fig. 123 (4, 5)].
Sinopotamon mayangense can be differentiated from S. nanlingense by the strongly bent (ca. 60°) terminal segment of the G1 [vs. less bent (ca. 45°)] and rounded outer margin of the terminal segment of the G1 (vs. distal third narrowed, so that the lateral margin is angular) [Figs. 12 a, b; Dai & Jiang 1991: Fig. 3 (3, 4); Dai 1999: Fig. 173 (4, 5)].
description: Published as part of Naruse, Tohru, Yeo, Darren C. J. & Zhou, Xianmin, 2008, Five new species of freshwater crabs (Crustacea: Decapoda: Brachyura: Potamidae) from China, pp. 49-68 in Zootaxa 1812 on pages 60-62, DOI: 10.5281/zenodo.182785