Calcipotamon Huang & Huang & Shen 2020, gen. nov.
Creators: name: Huang, Chao
name: Huang, Sheng-Zhuo
name: Shen, Zhi-Xin
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Potamidae
Calcipotamon

description: Genus Calcipotamon gen. nov.
urn:lsid:zoobank.org:act: D878905F-653F-48BC-A4B1-0568766AC8C8
(Chinese name: ḂĪäǟ]
(Figs. 1–3, 5)
Type species. Calcipotamon puglabrum gen. nov. et sp. nov., by current designation.
Diagnosis. Carapace broader than long, smooth allover, generally convex (Fig. 1); epigastric cristae smooth, low (Fig. 1); external orbital tooth prominent, sharp, separated from anterolateral margin by gap (Fig. 1). Median lobe of epistome broadly triangular (Fig. 2A). Maxilliped III with relatively broad ischium, exopod reaching beyond anterior edge of ischium, flagellum very short to absent (Fig. 3A). Cheliped palm surface smooth (Figs. 1, 3 F–G). Ambulatory legs very slender (Fig. 1). Male anterior thoracic sternum relatively narrow, width 1.5 × length (Fig. 2B). Male pleon narrowly triangular (Fig. 2C). Female pleon ovate (Fig. 4E). G1 generally slender, terminal segment elongated with basal flap (Fig. 3 C–E, H–I). G2 with long flagellum-like terminal segment (Fig. 3B). Female vulva positioned closely to one another, ovate, medium-sized, with relatively wide outer rim, reaching sternite suture V/VI but not VI/VII (Fig. 2F).
Etymology. The genus name is an arbitrary combination of Latin calcium and the type genus of Potamidae, Potamon. It alludes to the limestone habitat of the type species. Gender: neuter.
Distribution. Changjiang Li Autonomous County, Hainan Island, China.
Remarks. Calcipotamon gen. nov. is included in Potamiscinae sensu Yeo & Ng (2004). Although superficially similar to Neotiwaripotamon, the new genus can be separated by the smooth carapace (Fig. 1) (versus anterolateral and sub-orbital regions rugose, sub-hepatic and posterolateral striated in Neotiwaripotamon), low and smooth postorbital cristate (Fig. 1) (versus sharp in Neotiwaripotamon; Dai 1999: plate IV. figs. 2, 3), very short or absent flagellum of the maxilliped III exopod (Fig. 3A) (versus medium-length flagellum in Neotiwaripotamon; Dai 1999: fig. 40 (1), fig. 41 (1)), smooth cheliped palm surface (Fig. 1) (versus granulated in Neotiwaripotamon), very slender ambulatory legs (Fig. 1) (versus relatively stouter in Neotiwaripotamon; Dai 1999: plate IV. fig. 2, 3) and terminal segment of G1 with large basal flap (Figs. 3 C–E, H–I) (versus absent in Neotiwaripotamon; Dai 1999: figs. 40 (4), (5), 41 (4), (5)).
Calcipotamon gen. nov. is similar to Hainanpotamon in terms of G1 morphology, but can be immediately separated by its less swollen carapace (Fig. 1) (very convex in Hainanpotamon; Yeo & Naruse 2007: fig. 1), smooth carapace (Fig. 1, 2A) (Sub-orbital, sub-hepatic and pterygostomial granulated in Hainanpotamon; Yeo & Naruse 2007: fig. 1B), very short or absent flagellum of the maxilliped III exopod (Fig. 3A) (versus long flagellum in Hainanpotamon; Yeo & Naruse 2007: fig. 2A), epistome median lobe broadly triangular (Fig. 2A) (versus very broadly rounded in Hainanpotamon; Yeo & Naruse 2007: fig. 1B), relatively wider anterior thoracic sternum, width around 1.5 × length (Fig. 2B) (versus anterior thoracic sternites narrow in Hainanpotamon, width around 1.3 × length; Yeo & Naruse 2007: fig. 2D), slender legs (Fig. 1) (versus stout in Hainanpotamon; Yeo & Naruse 2007: fig. 1A).
Calcipotamon gen. nov. is also morphologically similar to Tiwaripotamon, but can be separated by the broadly triangular epistome median lobe (Fig. 2A) (versus very broadly rounded in Tiwaripotamon; Do et al. 2016: fig. 3B, 4B, 5B), narrowly triangular pleon (Fig. 2C) (versus broadly triangular in Tiwaripotamon; Dai 1999: fig. 184 (2), fig. 185 (2)) and terminal segment of G1 with large basal flap (versus small to no flap in Tiwaripotamon; Do et al. 2016: fig. 2A–F; Dai 1999: figs. 184 (4), (5), 185 (4), (5)).
description: Published as part of 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, pp. 447-456 in Zootaxa 4766 (3) on pages 448-452, DOI: 10.11646/zootaxa.4766.3.4, http://zenodo.org/record/3765589