Phylogenetic relationships and genetic diversity of thePolypedates leucomystaxcomplex in Thailand

Abstract

Taxonomic uncertainty of the Asian tree frog Polypedates leucomystax complex presents the challenging task of inferring its biogeographical history. Here, we describe its dispersion and the genetic relationships among different populations in Thailand, where we connect the population of the P. leucomystax complex of the Sunda Islands to the Indochina (mainland) population based on analyses of 266 sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Our maternal genealogy implies that there are four well-supported lineages in Thailand, consisting of Northern A (clade A: Polypedates sp.), Nan (clade B: P. cf. impresus), Southern (clade C: P. cf. leucomystax) and Northern D (clade D: P. cf. megacephalus), with Bayesian posterior probability >0.9. Phylogeny and haplotype networks indicate that clades A, B and D are sympatric. In contrast, clade C (P. cf. leucomystax) and clade D (P. cf. megacephalus) are genetically divergent due to the geographical barrier of the Isthmus of Kra, resulting in an allopatric distribution. Climatic conditions, in particular differences in rainfall on each side of the Isthmus of Kra, may play an important role in limiting the immigration of both clades. For the within-populations of either clades C or D, there was no significant correlation between geographic and genetic distance by the isolation-by-distance test, indicating intraspecific-dispersal of each clade. Population expansion occurred in clade C, whereas clade D showed a constant population. Taken together, the P. leucomystax complex in South East Asia may have diversified under climatic pressure, leading to allopatric and/or sympatric speciation.

Geographical differentiation and cryptic diversity in the monocled cobra, Naja kaouthia (Elapidae), from Thailand

“…This region is also known as a transition zone and plays an important role in diversity in other species (Hughes et al, 2003;Woodruff, 2003). Based on genetic data, comparisons among populations of the mainland Asian tree frog, Polypedates leucomystax (Buddhachat & Suwannapoom, 2018), gave similar results to our study in that the frogs were also divided into north-central, north-eastern and southern populations. The differentiation between northern and southern populations has also been reported in the king cobra (O. hannah) using phylogenetic analyses of ND2 and CR (Suntrarachun, Chanhome, & Sumontha, 2014), and other amphibian and reptile species (Inger & Voris, 2001).…”

“…Moreover, the distance between the island and the mainland could be important. Studies of N. kaouthia on Phuket Island (distance: ~0.5 km only) did not reveal any phenotypic difference between the island and mainland samples (Wüster & Thorpe, 1989, 1992Wüster et al, 1995), and the tree frog species, P. leucomystax, on Phuket Island displayed haplotypes shared with mainland populations (Buddhachat & Suwannapoom, 2018). However, no haplotypes of the Pha-ngan Island cobras were found to be shared with the mainland populations in this study ( Figure 3).…”

“…These features greatly restrict animal movement between regions, particularly for species with typically low vagility such as terrestrial snakes (Breininger, Bolt, Legare, Drese, & Stolen, 2011;Brito, 2003;Pyron & Burbrink, 2009). Similar findings of diversification within species have been reported for various taxa including the fighting fish, Betta smaragdina (Sriwattanarothai, Steinke, Ruenwongsa, Hanner, & Panijpan, 2010), the cardamom mountain horned agamid Acanthosaura cardamomensis (Wood et al, 2010), the bamboo pit viper, Trimeresurus macrops sensu stricto (Mrinalini et al, 2015), and species of the Asian tree frog, P. leucomystax (Buddhachat & Suwannapoom, 2018).…”

“…As shown for N. atra (Lin et al, 2014), our prediction was that geographically separated regions (Hughes, Round, & Woodruff, 2003;Woodruff, 2003) and temporal geological changes had the potential to facilitate divergence of N. kaouthia in Thailand (Buddhachat & Suwannapoom, 2018). The northern region is a mountainous area covered by many high, parallel mountain ranges that extend from the north, alternating with many deep valleys and steep rivers.…”

New freshwater mussel taxa discoveries clarify biogeographic division of Southeast Asia

“…This isthmus is a major biogeographic barrier corresponding to a putative ancient seaway 36,37 that influenced distribution ranges of a plethora of animal and plant taxa 38 and corresponds to the separation of the Oriental (Indo-Burmese) and Sundaland biotas 39 . A growing body of phylogeographic and phylogenetic research indicates that this barrier is reflected through abrupt changes in bird 40 , frog 41 , snake 42 , lizard 43 , giant centipede 44 and spider 45 assemblages around the Isthmus of Kra area. However, such examples are still poorly known among freshwater animals.…”