Tortomon puer Ng & Tri 2023, n. gen.
Creators: name: Huang, Chao
name: Wang, Jian
name: Shih, Hsi-Te
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Potamidae
Tortomon
Tortomon puer

description: Tortomon puer n. gen. n. sp.
(Figs. 1–3, 7A, B, 8A) urn:lsid:zoobank.org:act: A640B2B4-40C2-4EB8-8F92- 41311FF8B9BE
Material examined: Holotype: SYSBM 001836, male (21.8 × 16.1 mm), Simao District (22.66°N, 101.08°E), Pu’er City, Yunnan, China, mud burrow next to small hillstream, 1,500 m a.s.l., coll. C. Huang, July, 2018. Paratypes: SYSBM 001837-001838, 2 males (19.8 × 15.0 mm, 15.3 × 11.8 mm), same data as holotype. SYSBM 001839-001840, female (19.5 × 14.6 mm, 18.3 × 14.3 mm), same data as holotype. AM P.104575, male (19.5 × 14.8 mm), same data as holotype. NCHUZOOL 16431, 2 males (22.2 × 17.0 mm, 12.6 × 9.6 mm), same data as holotype.
© 2020 Academia Sinica, Taiwan
Description: Male: Small sized (CW <23 mm). Carapace broader than long, width 1.3 times length (n = 7), regions indistinct; dorsal surface smooth, finely pitted, convex (Fig. 1). Front deflexed, margin almost straight in dorsal view (Fig. 1). Epigastric cristae and postfrontal cristae smooth, low, inconspicuous (Fig. 1). Branchial regions swollen; cervical groove indiscernible; mesogastric region convex (Fig. 1). External orbital tooth inconspicuous; external orbital angle fused with anterolateral margin (Figs. 1, 2A). Epibranchial tooth indiscernible (Figs. 1, 2A). Anterolateral margin slightly cristate, lined with numerous fused granules (Figs. 1, 2A). Posterolateral surface smooth (Fig. 1). Orbits small, supraorbital and infraorbital margins ridged, smooth (Figs. 1, 2A). Sub-orbital, sub-hepatic and pterygostomial regions divided by sutures; surfaces smooth (Fig. 2A). Epistome median lobe broadly triangular, posterior margin slightly sinuous (Fig. 2A).
Maxilliped 3 merus width about 1.1 times length; ischium width about 0.7 times length; merus subtrapezoidal with median depression; ischium subtrapezoidal, with distinct median sulcus, mesial margin rounded; exopod strongly tapering, reaching to proximal quarter of merus height, flagellum absent (Fig. 3A).
Chelipeds unequal (Figs. 1, 3F–G). Merus trigonal in cross section, surfaces and margins smooth (Figs. 1, 2A). Carpus with blunt spine at inner-distal angle, spinule at base barely discernible, surfaces smooth (Fig. 1). Major cheliped palm length about 1.2–1.3 times height (n = 4); dactylus 1.1 times palm length (n = 4) (Fig. 3F, G). Palm surface smooth, pitted. Occlusal margin of fingers lined with triangular teeth of different size; small gape when closed, large gape in large males (Fig. 3F, G).
Ambulatory legs (P2–5) slender, with sparse short setae. P3 merus 0.6 times carapace length (n = 5). P5 propodus 2.2–2.4 times as long as broad (n = 5), shorter than dactylus (Fig. 1A).
Thoracic sternum generally smooth, pitted; sternites 1–4 wide, width 1.7 times length; sternites 1, 2 fused, forming a subtriangular structure; sternites 2, 3 fused, separated by a deep transverse sulcus; sternites 3, 4 fused, with deep “v” shaped sulcus (Fig. 2B). Sternopleonal cavity reaching anteriorly to level of midlength of chelipeds coxae base (Fig. 2B); median longitudinal groove separating sternites 7, 8 deep (Fig. 2D). Pleonal locking tubercle positioned at mid-length of sternites 5 (Fig. 2D).
Pleon narrowly triangular (Fig. 2C). Pleonites 3–6 progressively narrower, lateral margins almost straight; pleonite 6 1.8 times as broad as long; telson 1.3 times as broad as long, with blunt apex and concave lateral margins (Fig. 2C).
G1 generally straight and slender, reaching beyond pleonal locking tubercle in situ (Fig. 2D). Subterminal segment 2.8–2.9 times as long as terminal segment (n = 3), inner mesial margin slightly concave, outer mesial margin slightly convex. Terminal segment short, tapering, with blunt tip, pointed slightly outwards (Figs. 3C–E, 7A, B). G2 subterminal segment 2.3 times as long as terminal segment; terminal segment with thin coiled tip (Fig. 3B).
Female: Nonsexual characters similar to males. Major cheliped palm length about 1.3–1.4 times height (n = 2); dactylus 1.1 times palm length (n = 2) (Fig. 1B). P3 merus 0.6 times carapace length (n = 2). P5 propodus 2.2–2.3 times as long as broad (n = 2), shorter than dactylus (Fig. 1B). Vulva ovate, with relatively wide space between one another; medium-sized, mainly situated on sternite 6, reaching to sternite 5 but not sternite 7 (Fig. 2F). Pleon broadly ovate (Fig. 2E).
Etymology: The new species is named as a noun after the type locality, which is in Pu’er City, Yunnan.
Colour in life: Generally dark purple on dorsal surfaces with orbital margins, cheliped tips, joints of chelipeds and joints of ambulatory legs brightly orange (Fig. 8A).
Habitat: This species was collected from a small hillstream in a tea tree plantation at around 1,500 m a.s.l. In the initial sightings of this species by Z.-C. Zhou and J.-J. Zhou, they were found in the hillstream, underwater. All the specimens collected by the first author, however, were found in burrows in high density from a patch of wet ground at the hillstream bank. Therefore, it is likely that the new species is a semi-terrestrial burrower that prefers living in soft wet mud but also sometimes visits the stream.
Remarks: Tortomon puer n. sp. is very similar to Tortomon gejiu n. sp. in overall external morphology, but can be separated by its relatively narrower carapace (width of carapace 1.3 times the length versus width 1.4 times the length in Tortomon gejiu), the G1 terminal segment more is proportionately slender and points slightly outwards (Figs. 3C–E, 7A, B) (versus G1 terminal segment stouter, points upwards in Tortomon gejiu; Figs. 6C–E, 7C, D), and the G2 terminal segment is more slender, with the subterminal segment 2.3 times as long as the terminal segment (Fig. 3B) (versus G2 terminal segment stouter, subterminal segment 2.1 times as long as terminal segment in Tortomon gejiu; Fig. 6B, 7E). The two species can also be separated by their life colours in the field, with Tortomon puer sp. nov. being dark purple (Fig. 8A) and Tortomon gejiu being generally light brown to a light turquoise (Fig. 8B).
description: Published as part of Huang, Chao, Wang, Jian & Shih, Hsi-Te, 2020, A New Genus and Two New Species of Freshwater Crab (Crustacea: Brachyura: Potamidae) with Unusual Coiled Tip of Male Second Gonopods from Yunnan, Southwestern China, pp. 1-14 in Zoological Studies 59 (24) on pages 5-6, DOI: 10.6620/ZS.2020.59-24, http://zenodo.org/record/8069494