Phylogeny of long-legged flies genus phacaspis (Meuffels and grootaert, 1988) in peninsular Thailand

Abstract

The study of phylogenetic relationship of long-legged flies genus Phacaspis was focused on six coastal provinces along the Andaman and the Gulf of Thailand. The objective of this study was to determine phylogeny of long-legged flies genus Phacaspis in peninsular Thailand. Moreover, the specimens from Brunei and Singapore were used to resolve a phylogenetic relationship of genus Phacaspis in peninsular Thailand with adjacent areas. All specimens of Phacaspis mitis were collected using malaise trap, hand collection and net sweeping in the mangroves. The molecular phylogeny was analyzed based on COI, 12S rDNA, 16S rDNA and combined mitochondrial DNA genes. The phylogenetic tree of maximum likelihood analysis and Bayesian inference were congruent. The results revealed that P. mitis in peninsular Thailand was monophyletic group and also can be divided into two distinct clades. According to the haplotype network, 16 haplotype patterns of P. mitis were separated into two major haplotype networks. Furthermore, the result also showed that level of genetic distance (FST) between populations has influenced on geographical isolation (km). Moreover, the estimating of divergence time indicated that P. mitis in peninsular Thailand has arisen in late Eocene (35.55 Mya) and it was diverse during Plio- Pleistocene periods (3.14-0.51 Mya). The influence of the mangrove expansion and fragmentation plays an important role to the distribution of P. mitis in peninsular Thailand at that time. Likewise, the phylogenetic relationship of genus Phacaspis in peninsular Thailand, Singapore and Brunei was monophyletic group. The connectivity between patches of mangroves in Sundaland is suggested to be a major role to occurrence of genetic variation and gene flow in this genus.