First Evidence of Cryptic Species Diversity and Population Structuring of Selaroides leptolepis in the Tropical Western Pacific

The yellowstripe scad, Selaroides leptolepis (Carangidae), is an important fish commodity in the Tropical Western Pacific (TWP). It has a latitudinal range from south of Japan down to northern Australia, with highest concentration Southeast Asia. However, its TWP fishing grounds have long been hotspot unsustainable exploitations, thus threatening remaining wild populations. Despite species’ commercial significance, there limited understanding genetic structure and diversity. Herein, S. was examined using mitochondrial COI CytB sequences. Both markers denoted significant structuring based on high overall F ST values. Hierarchical analysis molecular variance (AMOVA), maximum likelihood (ML) phylogenetic trees, median-joining (MJ) haplotype networks strongly supported occurrence two allopatrically distributed lineages. These comprised widespread Asian lineage isolated Australian lineage. Within-lineage distances were low (K2P < 1%) whereas across-lineage remarkably > 6%), already comparable that interspecific carangid divergences. Haplotype sequence memberships, variations, geographic correlation suggested putative cryptic species. Historical demographic inferences also revealed species experienced rapid expansion commencing late Pleistocene, most likely during end Last Glacial Maximum (?20,000 years ago). present study encouraged application lineage-specific management efforts, as lineages are experiencing different evolutionary pressures. Overall, accurate knowledge distribution fundamental protecting diversity assuring stock sustainability.