Wednesday, November 3, 2021

[Crustacea • 2021] Geothelphusa boreas • A New Montane Freshwater Crab (Decapoda: Potamidae: Potamiscinae) from northeastern Taiwan, and the Identity of G. hirsuta Tan & Liu, 1998


Geothelphusa boreas  
 Shy, Shih & Mao, 2021

 
Abstract
A new freshwater crab is described from the montane area in northeastern Taiwan based on morphological and molecular evidence. Geothelphusa boreas sp. nov., from the Fushan Botanical Garden situated around New Taipei City and Yilan County, is distinct from similar congeners by the structure of the male first gonopod and the proportions of the male thoracic sternites. In addition, after comparing the holotypes of G. takuan and G. hirsuta Tan & Liu, 1998, no substantial difference could be found. Molecular evidence from mitochondrial cytochrome oxidase subunit I also supports the recognition of the new species and the conspecificity of G. hirsuta with G. takuan.
 
Key words: Crustacea, Potamidae, freshwater crab, new species, Geothelphusa boreasGeothelphusa hirsutaGeothelphusa takuan, Taiwan, mitochondrial. DNA, cytochrome oxidase subunit



   

Figure 2. Geothelphusa boreas sp. nov.
A, B, C, dorsal, frontal and ventral views of the holotype (NCHUZOOL 13615);
D, habitat in Dakeng Bridge, Suao, Yilan;
E, F, habitat in Shenmihu, Nan-ao, Yilan;
G, H, habitat in Tongshan, Nan-ao, Yilan.
 The arrows in E and G indicated the localities with crabs observed. The two rulers in H were used for a separate ecological study of the habitat.

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

Genus Geothelphusa Stimpson, 1858

Geothelphusa boreas sp. nov.

Diagnosis. Carapace length, width 1.7-, 2.3-times carapace height, respectively. Anterolateral margins distinct, lined with inconspicuous granules, without epibranchial tooth. Subterminal segment of G1 (Fig. 3A–C) curving inwards, outer proximal margin without tooth; terminal segment slightly curving outwards to almost straight; total length of G1 5.8 times terminal segment.  

Etymology. The species is derived from the Greek “boreas” (for north), alluding to the northernmost distribution of this species in the Central Range.


Jhy-Yun Shy, Hsi-Te Shih and Jean-Jay Mao. 2021. Geothelphusa boreas, A New Montane Freshwater Crab (Crustacea: Potamidae: Geothelphusa) from northeastern Taiwan, and the Identity of G. hirsuta Tan & Liu, 1998. Zootaxa. 5060(1); 93-104. DOI: 10.11646/zootaxa.5060.1.4