Phylogenetic analysis of Aciagrion Selys (Odonata: Coenagrionidae)

Abstract

ABSTRACT Odonates are useful biological indicators of environmental health because of their pollution-free habitat requirements and amphibiotic life cycle. Due to habitat destruction by industrial development, there is a need to name these odonates and obtain their genetic data to be used in understanding their evolutionary history for biodiversity conservation. Aciagrion is a poorly known and taxonomically difficult genus of oriental damselflies. Species of this genus cannot be distinguished on the basis of morphological characters alone as they are morphologically similar to the damselflies of other genera (Ischnura and Amphiallagma) and may also be referred to as cryptic species. Here, therefore, molecular studies are carried out to distinguish the species of this genus. The phylogenetic relationships of five species of genus Aciagrion have been explored using molecular (based on concatenated sequences of mitochondrial genes- COI, ND1 and 16S rRNA genes) as well as external morphological characters. Single-linkage cluster analysis of morphological data sets did not explain the relationships appropriately among the species of this genus as outgroup species were also retrieved within ingroup species. Interspecific genetic divergence, conserved, variable, parsimony-informative sites, nucleotide base composition and transition/transversion bias based on concatenated gene sequences have been calculated for these species. It is found that a multigene concatenation approach interprets phylogeny more appropriately than the morphological data alone. Presently, a COI gene fragment sequence for one species (the endemic Aciagrion hisopa), 16S rRNA gene fragments for four species and ND1 gene fragments for five species have been submitted for the first time to GenBank, and phylogenetic relationships based on three genes have also been determined for the first time. Aciagrion migratum is a new record from India.