Saturday, September 16, 2017

[Crustacea • 2016] Rathbunamon chumomrayense • A New Species of Semi-Terrestrial Freshwater Crab (Decapoda: Brachyura: Potamidae) from the Central Highlands of Vietnam

Rathbunamon chumomrayense
Do, Dang, Cao & Hoang, 2016

A new species of semi-terrestrial crab of the family Potamidae, Rathbunamon chumomrayense sp. nov. is described from Chu Mom Ray National Park, the Central Highlands of Vietnam. The new species can be distinguished from R. lacunifer (Rathbun, 1904), the only other species in the genus, by a suite of characters, including the slightly more rugose anterolateral regions, confluent epigastric and postorbital cristae that are sinuous, less convex anterolateral margins, relatively shorter fingers of the chelipeds, and the terminal segment of the male first gonopod being slightly curved outwards, with narrower dorsal flap.

Keywords: Crustacea, semi-terrestrial crabs, taxonomy

 The freshwater crabs of Vietnam are currently represented by 52 species, belonging to two families, Potamidae Ortmann, 1896 and Gecarcinucidae Rathbun, 1904 (Dang & Ho, 2012; Dang, Thai, & Pham, 1980; V.T. Do, 2014; V. T. Do, Le, & Nguyen, 2016; V. T. Do, Le, & Phan, 2015; V. T. Do, Shih, & Huang, 2016; Naruse, Nguyen Xuan, & Yeo, 2011; Ng & Yeo, 2001; Yeo & Ng, 1998; Yeo & Ng, 2007)Rathbunamon is a monotypic genus established by Ng (1996) with R. lacunifer (Rathbun, 1904) as the type species. A recent survey in the Central Highlands of Vietnam obtained two specimens which are here identified as a second species from this genus. The new species possesses the main generic characteristics of Rathbunamon. It appears to have a highly localized distribution and can be distinguished from its congener by a suite of morphological characteristics.

FIGURE 5. Rathbunamon chumomrayense sp. nov., on the forest ground in Chu Mom Ray National Park, Kon Tum Province, Vietnam.


Family Potamidae Ortmann, 1896
Subfamily Potamiscinae Ortmann, 1896 (sensu Yeo & Ng 2003)

Rathbunamon Ng, 1996

Rathbunamon chumomrayense sp. nov.

Etymology. The new species is named after the type locality, Chu Mom Ray.

Ecological notes. This species inhabits forested mountain areas. The larger specimen was found running around on the forest floor, far from the stream; however, the smaller specimen was found near the stream. It is believed that this species spends most of their time in the terrestrial environment

 Van Tu Do, Van Dong Dang, Thi Kim T. Cao and Ngoc Khac Hoang. 2016.  A New Species of Semi-Terrestrial Freshwater Crab (Crustacea: Decapoda: Brachyura: Potamidae) from the Central Highlands of Vietnam.   Zootaxa. 4179(2); 279–287.  DOI: 10.11646/zootaxa.4179.2.8