Historical abiotic events or human‐aided dispersal: inferring the evolutionary history of a newly discovered galaxiid fish

Ecology and Evolution

Gamuchirai Chakona²  Ernst R. Swartz¹ 

[1] South African Institute for Aquatic Biodiversity, Grahamstown, South Africa;Department of Ichthyology and Fisheries Science, Rhodes University, Grahamstown, South Africa

关键词: Cape Floristic Region;    Galaxias;    interbasin dispersal;    mitochondrial DNA;    nuclear DNA;    phylogeography;   

DOI  :  10.1002/ece3.1409

来源: Wiley

【 摘 要 】

Abstract

Range expansion of obligate freshwater fishes in the Cape Floristic Region (CFR) of South Africa has mostly been attributed to river capture events and confluence of rivers following sea-level regression. The role of low drainage divides and interbasin water transfers has received less attention. This study analyzed mitochondrial and nuclear DNA sequences to assess the processes that could have influenced the phylogeographic patterns of a newly discovered lineage of Galaxias zebratus (hereafter Galaxias zebratus “Joubertina”) that occurs across two currently isolated river systems close to the Joubertina area in the eastern CFR. Results from both analyses revealed that observed genetic differentiation cannot be explained by isolation between the two river systems. No genetic differentiation was found between the Krom River system and a population from one of the Gamtoos tributaries. Shallow genetic differentiation was found between the Krom and the other Gamtoos populations. Historical river capture events and sea-level changes do not explain the present distribution of Galaxias zebratus “Joubertina” across the Krom and Gamtoos River systems. Interbasin dispersal during pluvial periods, recent river capture, or recent human-mediated translocation seems to be the most plausible explanations.

【 授权许可】

CC BY   
© 2015 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.