Molecular evidence to support the transfer of Enteromorpha ovata to genus Ulva and evaluate its divergence using multi-locus time-calibrated phylogeny

Ulva has received considerable attention since its merger with tubular Enteromorpha (Linnaeus) Nees based on molecular evidence. Nevertheless, several nomenclatural and taxonomic proposals concerning tropical and subtropical species are still pending in want of investigations based on the altered circumscription and criteria of genetic diversity. Enteromorpha ovata Thivy et Visalakshmi ex H. Joshi et V. Krishnamurthy has a restricted geographical distribution only at Gopnath, India. In the present study, we for the first time provide a polyphasic approach to ascertain its taxonomic position, using morpho-anatomy, ecology and molecular taxonomy with multigene markers (rbcL, tufA and ITS rDNA). Phylogenetic analysis based on rbcL, tufA and ITS rDNA gene sequences supported the recognition of this species within the genus Ulva. The recent revision by Kumar and Palanisamy proposed the new nomenclatural combinaton Ulva ovata (Thivy et Visalakshmi ex Joshi et Krishnamurthy) Aron Santhosh Kumar and Palanisamy, but they did not give molecular evidence while doing so, which we accomplished. Our time-calibrated phylogeny suggested that U. ovata diverged from its respective sister lineages similar to 4.46 Mya in the Neogene period of the Cenozoic Era.