Calcipotamon, 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 : 448-452

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.3803454
persistent identifier	https://treatment.plazi.org/id/D878905F-653F-48BC-A4B1-0568766AC8C8
taxon LSID	lsid:zoobank.org:act:D878905F-653F-48BC-A4B1-0568766AC8C8
treatment provided by	Carolina
scientific name	Calcipotamon
status	gen. nov.

Treatment

Genus Calcipotamon View in CoL gen. nov.

urn:lsid:zoobank.org:act:D878905F-653F-48BC-A4B1-0568766AC8C8

(Chinese name: ḂĪäǟ]

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

Type species. Calcipotamon puglabrum View in CoL gen. nov. et sp. nov., by current designation.

Diagnosis. Carapace broader than long, smooth allover, generally convex ( Fig. 1 View FIGURE 1 ); epigastric cristae smooth, low ( Fig. 1 View FIGURE 1 ); external orbital tooth prominent, sharp, separated from anterolateral margin by gap ( Fig. 1 View FIGURE 1 ). Median lobe of epistome broadly triangular ( Fig. 2A View FIGURE 2 ). Maxilliped III with relatively broad ischium, exopod reaching beyond anterior edge of ischium, flagellum very short to absent ( Fig. 3A View FIGURE 3 ). Cheliped palm surface smooth ( Figs. 1 View FIGURE 1 , 3 View FIGURE 3 F–G). Ambulatory legs very slender ( Fig. 1 View FIGURE 1 ). Male anterior thoracic sternum relatively narrow, width 1.5 × length ( Fig. 2B View FIGURE 2 ). Male pleon narrowly triangular ( Fig. 2C View FIGURE 2 ). Female pleon ovate ( Fig. 4E View FIGURE 4 ). G1 generally slender, terminal segment elongated with basal flap ( Fig. 3 View FIGURE 3 C–E, H–I). G2 with long flagellum-like terminal segment ( Fig. 3B View FIGURE 3 ). 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 View FIGURE 2 ).

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 View FIGURE 1 ) (versus anterolateral and sub-orbital regions rugose, sub-hepatic and posterolateral striated in Neotiwaripotamon ), low and smooth postorbital cristate ( Fig. 1 View FIGURE 1 ) (versus sharp in Neotiwaripotamon ; Dai 1999: plate IV. figs. 2, 3), very short or absent flagellum of the maxilliped III exopod ( Fig. 3A View FIGURE 3 ) (versus medium-length flagellum in Neotiwaripotamon ; Dai 1999: fig. 40 (1), fig. 41 (1)), smooth cheliped palm surface ( Fig. 1 View FIGURE 1 ) (versus granulated in Neotiwaripotamon ), very slender ambulatory legs ( Fig. 1 View FIGURE 1 ) (versus relatively stouter in Neotiwaripotamon ; Dai 1999: plate IV. fig. 2, 3) and terminal segment of G1 with large basal flap ( Figs. 3 View FIGURE 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 View FIGURE 1 ) (very convex in Hainanpotamon ; Yeo & Naruse 2007: fig. 1), smooth carapace ( Fig. 1 View FIGURE 1 , 2A View FIGURE 2 ) (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 View FIGURE 3 ) (versus long flagellum in Hainanpotamon ; Yeo & Naruse 2007: fig. 2A), epistome median lobe broadly triangular ( Fig. 2A View FIGURE 2 ) (versus very broadly rounded in Hainanpotamon ; Yeo & Naruse 2007: fig. 1B), relatively wider anterior thoracic sternum, width around 1.5 × length ( Fig. 2B View FIGURE 2 ) (versus anterior thoracic sternites narrow in Hainanpotamon , width around 1.3 × length; Yeo & Naruse 2007: fig. 2D), slender legs ( Fig. 1 View FIGURE 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 View FIGURE 2 ) (versus very broadly rounded in Tiwaripotamon ; Do et al. 2016: fig. 3B, 4B, 5B), narrowly triangular pleon ( Fig. 2C View FIGURE 2 ) (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)).