Two deep evolutionary lineages in the circumtropical glasseye Heteropriacanthus cruentatus (Teleostei, Priacanthidae) with admixture in the south-western Indian Ocean.

A phylogeographic study of the circumtropical glasseye Heteropriacanthus cruentatus was conducted. Molecular analyses indicate two mitochondrial cytochrome c oxidase subunit I (coI) lineages that are 10·4% divergent: one in the western Atlantic (Caribbean) and another that was detected across the Indo-Pacific. A fixed single nucleotide polymorphism (SNP) was detected at a nuclear locus (S7 ribosomal protein) and is consistent with this finding. There is evidence of recent dispersal from the Atlantic to the Indian Ocean with individuals of mixed lineages detected in South Africa and the Mozambique Channel. Using coalescent analyses of the mitochondrial dataset, time of divergence between lineages was estimated to be c. 15·3 million years. The deep divergence between these two lineages indicates distinct evolutionary units, however, due to the lack of morphological differences and evidence of hybridization between lineages, taxonomic revision is not suggested at this time.