Phylogeographic Structure Of Co-Distributed, Upland Lineages Of Frogs And Snakes Across Mountain Tops In Peninsular Malaysia
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Date
2016-04
Authors
Quah, Evan Seng Huat
Journal Title
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Publisher
Universiti Sains Malaysia
Abstract
Montane regions around the world are areas of high diversity and endemism and Peninsular Malaysia is no different. The phylogeographic structure of three species of montane frogs, Metaphrynella pollicaris, Philautus petersi and Philautus vermiculatus and three genera of largely montane snakes, Macrocalamus, Calamaria and Popeia were compared to ascertain the relationships of the different allopatric populations. Field work was conducted at various montane sites across the country and specimens were collected for genetic comparison. Following PCR amplification for the ND1 or CytB mitochondrial genes, sequences were aligned, analysed using Bayesian and Maximum likelihood analyses and included in an integrative taxonomic analysis using colour pattern and morphology. The results reveal no single overarching pattern in the phylogenies of these co-distributed species across their range. Instead, the analyses reveal two very opposing phylogeographic patterns in the frogs and the snakes. The populations of frogs on separated mountain tops are very closely related to each other with only weakly supported substructuring observed in amongst the Metaphrynella pollicaris populations and no substructuring observed among the two species of Philautus. This fairly homogeneous genetic makeup observed, despite their geographic isolation, indicates a rapid range expansion in the recent past and that these populations have not had sufficient time to diverge in isolation. In contrast, the snakes revealed marked levels substructuring in their molecular phylogenies with deep divergences amongst allopatric populations. This indicates a much longer history of separation in these groups which have given the populations ample time to evolve along their own individual trajectories leading to their genetic differentiation and subsequent speciation. A new species of reed snake Macrocalamus emas sp. nov is described and a number of genetically distinct lineages that correspond to cryptic candidate species in need of future taxonomic reappraisal were uncovered within the genera Macrocalamus, Calamaria and Popeia. Although the distributions of the various taxa have been influenced by continuous changes from glacioeustatic driven climatic processes that affected the geography of Sundaland, the different ecologies and natural histories of these lineages have affected how they have responded and lead to their present day distributions. Overall, diversity in the snake genera has been underestimated and many cryptic lineages abound that are putative species awaiting formal recognition by more thorough comparisons. These discoveries have implications for the conservation of these narrow range upland endemics as the threat of global warming threatens to eliminate some of these undescribed species even before they are given formal taxonomic recognition.
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Keywords
Frogs and snakes