Tortomon puer, Ng & Tri, 2023

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, Zoological Studies 59 (24), pp. 1-14 : 5-6

publication ID	https://doi.org/ 10.6620/ZS.2020.59-24
DOI	https://doi.org/10.5281/zenodo.8055868
persistent identifier	https://treatment.plazi.org/id/4E0587D6-FF9A-2A0F-FC52-FEB9E4B5FEC1
treatment provided by	Valdenar
scientific name	Tortomon puer
status	gen. nov.

Treatment

Tortomon puer View in CoL View at ENA n. gen. n. sp.

( Figs. 1–3 View Fig View Fig View Fig , 7A, B View Fig , 8A View Fig ) 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 GoogleMaps . 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.

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 View Fig ). Front deflexed, margin almost straight in dorsal view ( Fig. 1 View Fig ). Epigastric cristae and postfrontal cristae smooth, low, inconspicuous ( Fig. 1 View Fig ). Branchial regions swollen; cervical groove indiscernible; mesogastric region convex ( Fig. 1 View Fig ). External orbital tooth inconspicuous; external orbital angle fused with anterolateral margin ( Figs. 1 View Fig , 2A View Fig ). Epibranchial tooth indiscernible ( Figs. 1 View Fig , 2A View Fig ). Anterolateral margin slightly cristate, lined with numerous fused granules ( Figs. 1 View Fig , 2A View Fig ). Posterolateral surface smooth ( Fig. 1 View Fig ). Orbits small, supraorbital and infraorbital margins ridged, smooth ( Figs. 1 View Fig , 2A View Fig ). Sub-orbital, sub-hepatic and pterygostomial regions divided by sutures; surfaces smooth ( Fig. 2A View Fig ). Epistome median lobe broadly triangular, posterior margin slightly sinuous ( Fig. 2A View Fig ).

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 View Fig ).

Chelipeds unequal ( Figs. 1 View Fig , 3F–G View Fig ). Merus trigonal in cross section, surfaces and margins smooth ( Figs. 1 View Fig , 2A View Fig ). Carpus with blunt spine at inner-distal angle, spinule at base barely discernible, surfaces smooth ( Fig. 1 View Fig ). Major cheliped palm length about 1.2–1.3 times height (n = 4); dactylus 1.1 times palm length (n = 4) ( Fig. 3F, G View Fig ). 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 View Fig ).

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 View Fig ).

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 View Fig ). Sternopleonal cavity reaching anteriorly to level of midlength of chelipeds coxae base ( Fig. 2B View Fig ); median longitudinal groove separating sternites 7, 8 deep ( Fig. 2D View Fig ). Pleonal locking tubercle positioned at mid-length of sternites 5 ( Fig. 2D View Fig ).

Pleon narrowly triangular ( Fig. 2C View Fig ). 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 View Fig ).

G1 generally straight and slender, reaching beyond pleonal locking tubercle in situ ( Fig. 2D View Fig ). 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 View Fig , 7A, B View Fig ). G2 subterminal segment 2.3 times as long as terminal segment; terminal segment with thin coiled tip ( Fig. 3B View Fig ).

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 View Fig ). 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 View Fig ). 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 View Fig ). Pleon broadly ovate ( Fig. 2E View Fig ).

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 View Fig ).

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 View Fig , 7A, B View Fig ) (versus G1 terminal segment stouter, points upwards in Tortomon gejiu ; Figs. 6C–E View Fig , 7C, D View Fig ), and the G2 terminal segment is more slender, with the subterminal segment 2.3 times as long as the terminal segment ( Fig. 3B View Fig ) (versus G2 terminal segment stouter, subterminal segment 2.1 times as long as terminal segment in Tortomon gejiu ; Fig. 6B View Fig , 7E View Fig ). The two species can also be separated by their life colours in the field, with Tortomon puer sp. nov. being dark purple ( Fig. 8A View Fig ) and Tortomon gejiu being generally light brown to a light turquoise ( Fig. 8B View Fig ).