Semicirculara lincangensis Chu & Wang & Sun 2018, sp. nov.
Creators: name: Chu, Kelin
name: Wang, Pengfei
name: Sun, Hongying
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Potamidae
Semicirculara
Semicirculara lincangensis

description: Semicirculara lincangensis sp. nov.
(Figs. 2–5)
Material examined. Holotype, male (adult), 18.8 × 14.4 mm, NNU 160562, Daogeng village (23°12’52’’N 99°24’42’’E, 1676 m asl), Danjia Town, Cangyuan County, Lincang City, Yunnan Province, coll. Kelin Chu, Pengfei Wang & Hongying Sun, 10 May 2016. Paratypes: 1 female (adult), 20.2 × 15.9 mm, NNU 160567, same data as holotype (allotype); 2 males (adult), 18.4 × 14.2 mm, NNU 160561; 21.1 × 15.8 mm, NNU 160563, same data as holotype; 1 male (adult), 16.3 × 13.3 mm, NNU 160566, 1 female (adult), 15.9 × 12.6 mm, NNU 160568, same data as holotype (to be deposited in IZCAS).
Comparative material. Pararanguna semilunatum (Dai & Chen, 1985): 1 male (16.9 × 13.3 mm), NNU 151005; 1 female (22.3 × 17.1 mm), NNU 151103; Baoshan, Yunnan, coll. Oct 2015. Aparapotamon inflomanum Dai & Chen, 1985: 1 male (16.8 × 13.6 mm), NNU 142201, Xianggelila, Yunnan, coll. Sep 2015; 1 female (21.6 × 17.9 mm), NNU 142202; Xianggelila, Yunnan, coll. Sep 2015.
Diagnosis. As for genus.
Description. Carapace about 1.3 times broader than long (n=4), punctate, glabrous, dorsal surface strongly convex longitudinally and transversely, regions distinctly defined; epibranchial region rugose, mesobranchial and metabranchial region glabrous (Fig. 2A). Cervical groove indistinct; H-shaped groove between gastric and cardiac regions distinct; postfrontal lobe convex, separated medially by a “Y” shaped groove extending to the frontal region; postorbital cristae distinct, not sharp, postorbital region concave (Fig. 2A, B). Front deflexed downwards, anterior border emarginated medially (Fig. 2A, B). Anterior margin of epistome slightly sinuous; triangular median lobe of posterior margin with granules. Dorsal orbital margin ridged, external orbital angle triangular, outer margin lined with six small granules (Fig. 2A, B). Eyes, orbits large, tip of cornea nearly reaching tip of external orbital tooth (Fig. 2B). Epibranchial tooth small, granular, distinct, clearly demarcated from external orbital tooth by Vshaped notch (Fig. 2A). Anterolateral margin cristate, lined with granules (Fig. 2A).
Third maxilliped merus about 1.1–1.2 times as broad as long (n=4), trapezoidal, with median depression; ischium about 1.3–1.5 times as long as broad (n=4), rectangular, with distinct median sulcus; exopod reaching proximal 1/3 of merus length, without flagellum (Fig. 3B).
Male thoracic sternum generally smooth (Fig. 2C); sternites 1, 2 completely fused to form triangular structure; sternites 2, 3 separated by continuous suture; groove between sternites 3, 4 present; sterno-pleonal cavity deep and broad; within, inter-sternite sutures interrupted medially (i.e. sutures 4/5, 5/6, and 6/7); median line between sternites 7, 8 moderately long (Fig. 4A).
Chelipeds slightly unequal, right cheliped large in holotype (Fig. 2A); merus trigonal in cross-section; margins crenulated; carpus with sharp spine on inner distal angle, with granules at base; outer surfaces of larger manus glabrous, larger manus about 1.2–1.4 times as long as high (n=4), about as long as movable finger, fingers claw shaped distally, gape narrow when fingers closed, cutting edge lined with low teeth (Fig. 3A). Ambulatory legs slender, unarmed; dactylus slender, with stiff, spine-like setae (Fig. 2A); second ambulatory leg merus about 1.4– 1.6 times as long as dactylus (n=4).
Male pleon triangular; somites 1 and 2 longitudinally short; third somite widest; somites 4 and 5 progressively trapezoidal; sixth somite width 2.2 times length (n=4); telson triangular, tip rounded, with proximal width about 1.1–1.2 times length (n=4; Fig. 2C, 4B).
G1 long, tip of terminal segment reaching suture between thoracic sternites 4, 5 in situ (Fig. 4A); subterminal segment about 1.7 times as long as terminal segment; terminal segment slightly elongated inward (Fig. 3D; 5A), distal part of terminal segment elongated with ventrally directed semicircular lobe (Fig. 3C, D; 5A; 10A, B); G2 slightly shorter than G1, subterminal segment about 1.8 times as long as terminal segment (Fig. 3E).
Female pleon longitudinally elongated, ovate; sixth somite about 3.0 times as broad as long (n=2), telson semicircular, tip slightly acute, about 1.9–2.0 times as broad as long (n=2; Fig. 4C). Female vulvae appearing to be
situated between thoracic sternites 5 and 6 in situ, ovate, deep, posteromesial margin with barely raised, nearly flat, rim, opening inward (Fig. 4D).
Distribution and habitat. Semicirculara lincangensis gen. & sp. nov. was found in moist burrows near a small mountain stream in Daogeng Village (23°12’52’’N 99°24’42’’E), Danjia Town, Cangyuan County, Lincang City in Yunnan Province, China (Fig. 1); at an altitude of 1676 m. They are residing in burrows under bushed ground during the day.
Live coloration. Carapace is usually dark brown, while chelipeds and ambulatory legs are usually brown in life.
Etymology. Semicirculara lincangensis sp. nov. is named after the type locality, Lincang City in Yunnan Province, China.
description: Published as part of Chu, Kelin, Wang, Pengfei & Sun, Hongying, 2018, A new genus and species of primary freshwater crab and a new species of Artopotamon Dai & Chen, 1985 (Crustacea, Brachyura, Potamidae) from western Yunnan, China, pp. 115-131 in Zootaxa 4422 (1) on pages 118-121, DOI: 10.11646/zootaxa.4422.1.7, http://zenodo.org/record/1455529