Phylogeography of Two Drepaneid Fishes (Drepane punctata and Drepane longimana) in the Indo-West Pacific

Articles in Press

Document Type : Original Article

Author

Mehdi Ghanbarifardi

Department of Biology, Faculty of Science, University of Sistan and Baluchestan, Zahedan, Iran

10.22067/ijab.2026.97180.1118

Abstract

This study provides the first comprehensive phylogeographic analysis of two morphologically similar species of the family Drepaneidae, Drepane punctata and D. longimana, across their distribution in the Indo-West Pacific (IWP). Utilizing mitochondrial DNA sequences of the cytochrome c oxidase I (COI) gene, we assessed genetic distinctness and population structure across diverse geographic regions. A total of 59 sequences of D. punctata and 20 sequences of D. longimana were analyzed, revealing significant contrasts in genetic diversity and demographic histories. D. punctata exhibited low nucleotide diversity (π = 0.0041) and moderate haplotype diversity (Hd = 0.788), indicative of a recent population expansion characterized by a star-like haplotype network. In contrast, D. longimana displayed much higher nucleotide diversity (π = 0.0627) and high haplotype diversity (Hd = 0.874), reflecting older lineage diversification and a stable demographic history, as evidenced by non-significant neutrality tests. Analysis of molecular variance (AMOVA) indicated significant population structure in both species, with D. punctata showing high gene flow among proximate populations in Southeast Asia, while D. longimana exhibited profound genetic isolation among most sampled regions. These findings suggest that D. longimana may represent a complex of cryptic species, akin to the pattern observed in the squaretail mullet, Ellochelon vaigiensis, and emphasize the need for further taxonomic investigation. This study enhances our understanding of marine speciation and population dynamics within the IWP, revealing complex evolutionary histories shaped by past and present environmental factors.

Keywords

Cryptic speciation

genetic diversity

demographic history

haplotype network

biogeography

Subjects

• Biochemical and Molecular Population Genetics

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