Two new species and the molecular phylogeography of the freshwater crab genus Bottapotamon (Crustacea: Decapoda: Brachyura: Potamidae).

Ning Gao,Song-Bo Wang,Ying-Yi Cui,Jie-Xin Zou

doi:10.7717/peerj.7980

Abstract

Bottapotamon chenzhouense sp. n. and B. luxiense sp. n. are described from Hunan Province and Jiangxi Province, respectively. These species both have diagnostic features of the genus Bottapotamon and discernible characteristics as new species. B. chenzhouense sp. n. can be distinguished from co-geners by features such as the G1, which has a fold covering the surface of the entire subterminal article with a distal region. B. luxiense sp. n. has an elliptical carapace, and a sturdy and blunt terminal article of G1. The molecular phylogeny and biogeography of the genus Bottapotamon (Decapoda: Brachyura: Potamidae) were studied, using mitochondrial cytochrome oxidase I (mtDNA COI), 16S rRNA and nuclear histone H3 gene fragments. The results support the assignment of the two new species to the genus Bottapotamon. In addition, the divergence time of the genus Bottapotamon was estimated to be 3.49–1.08 Ma, which coincided with various vicariant and dispersal events that occurred in the geological area where the genus Bottapotamon is commonly distributed. Mountains appear to have played an important role in the distribution of this genus. The Wuyi Mountains gradually formed offshore and inland of southeastern China by the compression of the Pacific plate and the Indian plate in the Neogene-Quaternary, and the Luoxiao Mountains formed continuously in the continued forming in the north-south direction because of neotectonic movement, have resulted in the geographical distribution pattern of the genus Bottapotamon, which was also established gradually.

Highlights

The genus Bottapotamon is a unique genus of freshwater crabs from the China mainland
In mainland China, the genus Bottapotamon is primarily distributed in the Wuyi Mountain Range area; B. luxiense sp. n., B. youxiense, B. nanan, B. engelhardti and B. yonganense are restricted within an area east of the Wuyi Mountain Range (Fig. 1)
This study reports two new species of genus Bottapotamon, B. chenzhouense sp. n., which was first discovered in Chenzhou City, Hunan Province, in south of Luoxiao Mountains, and B.luxiense sp. n., which is distributed in north of the Luoxiao Mountains (Fig. 1)

Summary

Introduction

The genus Bottapotamon is a unique genus of freshwater crabs from the China mainland. In 1997, three species of the genus Malayopotamon on (Bott, 1967; Cheng, Lin & Luo, 1993; Dai et al, 1979) and one new species were identified as Bottapotamon on the basis of its morphological characteristics, such as the form of carapace and first gonopod (G1) (Türkay & Dai, 1997). The genus Bottapotamon contained B. fukiense (Dai et al, 1979), B. engelhardti (Bott, 1967), B. yonganense Two new species and the molecular phylogeography of the freshwater crab genus Bottapotamon (Crustacea: Decapoda: Brachyura: Potamidae).

Methods

Results

Discussion

Conclusion