# Phylogenetic Variation of Periophthalmus Species Living in the Mekong Delta, Vietnam, Using Cytb Sequence

## TL;DR

This study uses genetic analysis to explore the evolutionary relationships of three mudskipper species in Vietnam's Mekong Delta.

## Contribution

The study reveals distinct genetic divergence and phylogenetic sub-clades among Periophthalmus species using Cytb gene analysis.

## Key findings

- Three Periophthalmus species formed distinct sub-clades with high genetic divergence (15%–18%).
- Phylogenetic sub-clades were supported by 100% bootstrap values and morphological differences.
- The study enhances understanding of the evolutionary history of amphibious fish in the Mekong Delta.

## Abstract

Mudskippers are amphibious fish that breathe air and have adapted to living on mudflats. They possess unique morphological, physiological, and behavioral features that set them aside from fish that live entirely in water. These characteristics may also have an impact on their phylogenetic and phylogeographical aspects. A study investigated the genetic relationships of mudskippers of the genus Periophthalmus found in four mudflat areas in the Mekong Delta. The outcomes of the Cytb phylogenetic tree analysis of the genus Periophthalmus revealed that the three species of Periophthalmus, namely
Periophthalmus chrysospilos
,
Periophthalmus gracilis
, and
Periophthalmus variabilis
, separated into three sub‐clades. The sub‐clades showed a high degree of genetic divergence and were supported by a bootstrap value of 100%. Thus, the Cytb gene analysis technique helped to reconstruct the genetic relationship of these three mudskipper species of the genus Periophthalmus. This study provided an essential understanding of the evolutionary history of mudskippers and shed light on the phylogenetic and phylogeographical characteristics of this unique group of amphibious fish.

This study investigates the genetic relationships of three Periophthalmus mudskipper species (
P. chrysospilos
,
P. gracilis

, and
P. variabilis
) from the Mekong Delta using mitochondrial cytochrome b (Cytb) gene analysis. The findings reveal significant interspecific genetic divergence (15%–18%) and distinct phylogenetic sub‐clades supported by morphological differences and high bootstrap values. These results provide valuable insights into the evolutionary history and genetic diversity of amphibious fish in this region.