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ESR prepress abstract   -  DOI: https://doi.org/10.3354/esr01152

Pleistocene paleodrainages explain the phylogeographic structure of Malaysian populations of Asian arowana better than their chromatic variation

Norli Fauzani Mohd Abu Hassan Alshari, Sébastien Lavoué*, Mohamad Asyraf Mohamad Sulaiman, Md. Zain Khaironizam, Mohd Nor Siti-Azizah, Fazimah Aziz

*Corresponding author:

ABSTRACT: Little is known about the genetic structure and phylogeography of Asian arowana. Natural variation in body color has been noticed for a long time, leading to the informal distinction of chromatic varieties. Previous studies that attempted to genetically characterize these varieties did not comprehensively cover their geographical distribution. In Malaysia, about 10 drainage-restricted populations of Asian arowana are known that are currently classified into 2 species and 3 color-varieties. In this study, we used three molecular markers to test 2 hypotheses explaining the relationships among 9 of these populations. The first hypothesis postulates that each color variety forms a monophyletic group, whereas the second hypothesis assumes that Pleistocene paleodrainages shaped the distribution of these populations. We found that the overall genetic variability is low within Asian arowana and the green variety is non-monophyletic with other varieties nested within. Instead, the populations of Malaysia belong to 3 genetic lineages that are allopatrically distributed. The ages and distribution of 2 of these lineages are rather consistent with past connections through paleodrainages, whereas the last lineage is restricted to Central Sarawak. Overall, our results reject the first hypothesis, demonstrating that the geographic origin of specimens is a better phylogenetic indicator than their body color. This study highlights the importance of Malaysia in the conservation of Asian arowana because it is the only country that embraces populations of all 3 main genetic lineages.