Calcipotamon puglabrum, Huang & Huang & Shen, 2020

Huang, Chao, Huang, Sheng-Zhuo & Shen, Zhi-Xin, 2020, A new long-legged terrestrial freshwater crab, Calcipotamon puglabrum gen. nov et sp. nov. (Crustacea: Decapoda: Potamidae), from Hainan Island, China, Zootaxa 4766 (3), pp. 447-456 : 452-454

publication ID	https://doi.org/ 10.11646/zootaxa.4766.3.4
publication LSID	urn:lsid:zoobank.org:pub:739BB73C-0A2B-45C6-852A-A2596F897647
DOI	https://doi.org/10.5281/zenodo.3803448
persistent identifier	https://treatment.plazi.org/id/039C8784-FFAB-5C3C-FF70-868ED76CF8C4
treatment provided by	Carolina
scientific name	Calcipotamon puglabrum
status	gen. nov. et sp. nov.

Treatment

Calcipotamon puglabrum View in CoL gen. nov. et sp. nov.

urn:lsid:zoobank.org:act:48E1B266-D473-4754-ABE1-BF56FCEDBDC

[Chinese name: ÄẌṘĀae]

( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 , 5 View FIGURE 5 )

Type material. Holotype: SYSBM 001961 , male (31.6 × 24.5 mm), Wangxia Village (19.00°N, 109.15°E), Changjiang Li Autonomous County, Hainan Province, China, rock crevice in karst forest, 600-900 m a.s.l., coll. C. Huang, June, 2019 GoogleMaps . Paratypes: SYSBM 001962, male (30.3 × 23.8 mm), same data as holotype. SYSBM 001963-001964, 2 females (39.7 × 30.9 mm, 31.5 × 24.6 mm), same data as holotype. AM P.104569, male (29.3 × 22.6 mm), same data as holotype. AM P.104570, female (30.4 × 23.7 mm), same data as holotype.

Description. Carapace broader than long, width 1.3 × length (n = 6), regions indistinct. Dorsal surface smooth, finely pitted, convex ( Fig. 1 View FIGURE 1 ). Front deflexed, margin slightly ridged in dorsal view ( Fig. 1 View FIGURE 1 ). Epigastric cristae low, blunt, divided by a narrow gap ( Figs. 1 View FIGURE 1 , 2A View FIGURE 2 ). Postorbital cristae smooth, very low ( Fig. 1 View FIGURE 1 ). Branchial regions swollen; cervical groove very shallow; mesogastric region convex ( Fig. 1 View FIGURE 1 ). External orbital tooth prominent, sharp, triangular with almost straight outer margins, separated from anterolateral margin by gap ( Figs. 1 View FIGURE 1 , 2A View FIGURE 2 ). Epibranchial tooth blunt ( Figs. 1 View FIGURE 1 , 2A View FIGURE 2 ). Anterolateral margin cristate, lined with smoothly fused granules. Posterolateral surface smooth ( Fig. 1 View FIGURE 1 ). Orbits large, supraorbital and infraorbital margins ridged, smooth ( Figs. 1 View FIGURE 1 , 2A View FIGURE 2 ). Sub-orbital, subhepatic and pterygostomial regions divided by sutures; surfaces smooth ( Fig. 2A View FIGURE 2 ). Epistome median lobe broadly triangular, lateral margins sinuous ( Fig. 2A View FIGURE 2 ).

Maxilliped III merus width about 1.1 × length; ischium width about 0.7 × length; merus subtrapezoidal with median depression; ischium subtrapezoidal, with distinct median sulcus, mesial margin rounded; exopod reaching to proximal one-fifth of merus height, flagellum very short to absent ( Fig. 3A View FIGURE 3 ).

Chelipeds (pereiopod I) unequal ( Figs. 1 View FIGURE 1 , 3 View FIGURE 3 F–G). Merus trigonal in cross section, margins weakly crenulated, surfaces generally smooth ( Figs. 1 View FIGURE 1 , 2A View FIGURE 2 ). Carpus with sharp spine at inner-distal angle, spinule at base, surfaces smooth ( Fig. 1 View FIGURE 1 ). Major cheliped palm length about 1.5–1.6 × height in males (n = 2), 1.5–1.7 × in females (n = 3); dactylus 0.9–1.0 × palm length in both males (n = 2) and females (n = 3) ( Fig. 3 View FIGURE 3 F–G). Palm surface smooth, pitted. Occlusal margin of fingers lined with large and small blunt, round teeth; small gape when closed ( Fig. 3 View FIGURE 3 F–G).

Pereiopods II–V (first to fourth ambulatory legs) slender, smooth. Pereiopod III merus 0.9 × carapace length in males (n = 3) and females (n = 2). Pereiopods V propodus 3.8–4.0 × as long as broad in males (n = 3), and 4.0–4.1 × in females (n = 3), shorter than dactylus ( Fig. 1 View FIGURE 1 ). Male thoracic sternum generally smooth, pitted; sternites I–IV relatively narrow, width 1.5 × as length. Sternites I, II fused, forming a subtriangular structure; sternites II, III fused, separated by a deep transverse sulcus; sternites III, IV fused, with inconspicuous sulcus ( Fig. 2B View FIGURE 2 ). Male sterno-pleonal cavity reaching anteriorly to level of midlength of chelipeds coxae base ( Fig. 2B View FIGURE 2 ); median longtitudinal groove separating sternites VII, VIII deep ( Fig. 2D View FIGURE 2 ). Male pleonal locking tubercle positioned posterior to mid-length of sternites V ( Fig. 2D View FIGURE 2 ). Female vulva ovate, medium-sized, with relatively wide outer rim, reaching sternite suture V/VI but not VI/VII; positioned closely to one another, orientation slightly oblique to the longitudinal axis of pleon ( Fig. 2F View FIGURE 2 ).

Pleon narrowly triangular in males ( Fig. 2C View FIGURE 2 ) and broadly ovate in females ( Fig. 2E View FIGURE 2 ). Male pleonites III–VI progressively narrower, lateral margins almost straight; pleonite VI 2.1 × as broad as long; telson 1.4 × as broad as long, with blunt apex ( Fig. 2C View FIGURE 2 ).

G1 generally slender, reaching beyond the pleonal locking tubercle but not to sternites IV/V suture in situ ( Fig. 2D View FIGURE 2 ). Subterminal segment 2.7–2.9 × as long as terminal segment (n=3), tapering anteriorly, inner margin slightly convex to convex, outer margin slightly concave. Terminal segment elongated, basal region curved anterolaterally, apex pointed anteriorly, with large rounded basal flap and sharp tip ( Fig. 3 View FIGURE 3 C–E, H–I). G2 subterminal segment 1.7–1.9 × as long as the flagellum-like terminal segment (n=3) ( Fig. 3B View FIGURE 3 ).

Etymology. The species name is an arbitrary combination of Latin “purpura” and “glaber”, which means purple and smooth. The name is used as a noun in apposition.

Colour in life. Generally dark purple. Joints of chelipeds and ambulatory legs, orbit margins, posterior margin of epistome and upper inner margins of pterygostomial regions orange ( Fig. 5A View FIGURE 5 ).

Habitat. This terrestrial species is found from a karstic mountain where they hide in the water-filled crevices of limestone outcrop formed by weathering ( Fig. 5B View FIGURE 5 ). Suitable crevices were almost all occupied by at least one crab at the type locality. The new species possesses slender legs which give it increased climbing abilities and mobility on land, which is likely an adaptation to the volatile nature of their preferred habitat and their predatory nature. One specimen was found residing inside a water-filled tree hole, suggesting some plasticity in habitat choice. Several ovigerous females were found during our collection in June but were released after inspection. No other potamids were observed at the type locality.

Remarks. See remarks for genus.

Distribution. Wangxia Village, Changjiang Li Autonomous County, Hainan, China.