Latopotamon xuanweiense 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
Latopotamon
Latopotamon xuanweiense

description: Latopotamon xuanweiense spec. nov.
(Figs. 1–3)
Material examined. Holotype: male, 20.2× 25.4 mm, NCU MCP 2008.0001, Xuanwei City (ca. 26°12’47’’N 104°06’40’’E), Yunnan Province, coll. Haiyan Yang & Xianmin Zhou, 18 Aug. 2005.
Paratypes: 2 males, 18.2×22.6, 21.0× 26.2 mm, 3 females, 19.8×26.0–20.8× 27.1 mm, NCU MCP 2008.0002, data same as holotype; 3 males, 14.8×18.4–19.4×25.0 mm, 2 ovigerous females, 19.4×24.5, 21.0× 27.3 mm, 2 females, 12.8×16.1, 20.8× 26.8 mm, ZRC 2008.0013, data same as holotype; 3 males, 15.6×19.4–18.8× 23.9 mm, 3 females, 18.7×23.4–21.0× 27.8 mm, NMNS-5751-001, data same as holotype.
Description. Carapace (Fig. 1 a) broader than long, widest across posterior parts of anterolateral margins, CW 1.24–1.32 times (mean = 1.27, n = 15) CL; dorsal surface flat, smooth; epigastric crista slightly raised, postorbital crista slightly raised, not connected to epibranchial tooth, cervical groove indistinct, H-shaped gastric groove shallow but distinct. Front distally deflexed, concave medially. Supra-, infraorbital margins (Fig. 1 b) cristate, not granulated; suborbital, pterygostomial regions smooth. External orbital angle low, directed anterior-inward, outer margin about 4 times longer than inner margin; epibranchial tooth small, anterolateral margin shorter than posterolateral margin, lined with granules. Antennular fossa oblong; epistome with posterior margin cristate, not granulated, with 5 lobes, median longest, triangular, submedian shortest, rounded.
Palp of mandible three-segmented, with terminal segment simple. Third maxilliped (Figs. 1 b, 2) rectangular, midlength of ischium less than 2 times that of merus, exopod reaching proximal third of outer margin of merus, flagellum short.
Thoracic sternites 2, 3 (Fig. 2) demarcated by distinct suture, suture between sternites 3, 4 indiscernible. Abdominal cavity reaching imaginary line joining posterior margins of cheliped coxae, cavity relatively narrow, distance between inner ends of sutures between thoracic sternites 4, 5 wider than half length of distance between sternal condyles; sternal condyle positioned slightly proximal to middle of thoracic sternite 5; single line of long brown setae along posterior parts of sutures between sternites 4, 7, lines reaching inner ends of sutures; thoracic sternite 8 demarcated medially by uninterrupted longitudinal median line, without transverse ridge at inner ends of sutures between thoracic sternites 7, 8.
Chelipeds subequal in males (Fig. 1 a), major cheliped slightly stouter than minor; merus granulated on dorsal, ventral margins, granules larger on dorsal margin, subdistal tooth on ventral surface small; carpus with long, sharp inner angle, small protuberance below base of inner angle; palm with moderately convex outer surface, smooth, height two-thirds of length; fingers shorter than palm, gape narrow when chela closed, cutting edge lined with low teeth.
Ambulatory legs (Fig. 1 a) short, almost glabrous, second, third legs longest when stretched laterally, surfaces rough, merus with acute subdistal angle on anterior margin; dactyli longer than respective propodi.
Male first abdominal segment with transverse ridge; third segment widest, lateral margins of third to six segments not strongly convergent distally; telson triangular, width 1.82–2.00 times length (mean = 1.90, n = 3), 1.08–1.26 times (mean = 1.16, n = 3) longer than sixth segment, sixth segment width 2.55–2.67 times length (mean = 2.61, n = 3). G1 (Figs. 3 a–c) short, stout, subdistal segment swollen proximal-outwards, dorsal layer expanded inwards, outer ventral layer with longitudinal suture along inner margin; boundary between subterminal, distal segment membrane-like; distal segment bent dorsal-outward almost perpendicularly; proximal-outer part distinctly swollen, opening on distal end, directed posterior-outward. G2 (Fig. 3 d) longer than G1, flagellum about 2 times length of narrowed part of basal segment.
Etymology. The species is named after the type locality, Xuanwei City, Yunnan Province, China.
Distribution and habitat. Latopotamon xuanweiense spec. nov. is known only from the type locality (Xuanwei City, Yunnan Province, China; 1,949 m asl.). The species was found from under stones in the water with depth of about 25 cm. The water temperature was 17 and the pH was 6.0.
Remarks. Dai & Türkay (1997) established a monotypic genus Latopotamon for Isolapotamon obtortum Dai, Song, Li, Chen, Wang & Hu, 1984, with the diagnostic characters of a broad and shallow median groove of the thoracic sternum and short, stout and strongly bent G1. The G1 of Latopotamon xuanweiense spec. nov. is similar to that of L. obtortum. However, it can be differentiated from that of L. obtortum by having a rounded tip (vs. tip pointed medially), the inner margin of the subterminal segment being strongly expanded proximally (vs. inner margin of the subterminal segment slightly expanded submedially), and a large hump on the outer proximal part of the terminal segment (vs. hump smaller) [Figs. 3 a–c; Dai et al. 1984: Fig. 12; Dai & Türkay 1997: Fig. 11 (4, 5); Dai 1999: Fig. 235 (6, 7)].
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 50-51, DOI: 10.5281/zenodo.182785