Molecular phylogeny and genetic diversity of some <i>Lepidagathis</i> species (Acanthaceae) based on nuclear and chloroplast regions

<i>Lepidagathis</i> Wild., a pantropical genus belonging to the tribe Barlerieae, contains ∼147 species. Considerable morphological work has been done on <i>Lepidagathis</i>, but some taxonomical doubts and contrasting interpretations still persist. Molecular analysis is the best tool to resolve the taxonomic doubts, but few nucleotide sequence data are available to date on <i>Lepidagathis</i>. Recently, some phylogenetic and morphological studies have proposed the inclusion of <i>Teliostachya</i> and <i>Lophostachys</i> in <i>Lepidagathis</i>. This work constitutes the first phylogenetic analysis of some <i>Lepidagathis</i> species based on chloroplast and nuclear regions. Both Bayesian and Maximum Likelihood phylogenetic analyses divide studied <i>Lepidagathis</i> species into two main clades, i.e. Clade A and B and place the Indian endemic <i>Lepidagathis</i> in Clade A with strong support. Phylogeny based on combined data resolve <i>Lepidagathis</i>, <i>Barleria</i>, and <i>Crabbea</i> lineages with stronger support than nrITS and cpDNA phylogenies. This phylogenetic study supports previous systematic revisions about the inclusion of <i>Lophostachys</i> and <i>Acanthura</i> species in <i>Lepidagathis</i> as well as the inclusion of <i>Golaea</i> and <i>Acanthostelma</i> into <i>Crabbea</i> species. In conclusion, this study constitutes a baseline molecular phylogeny for <i>Lepidagathis</i> and, in particular, contributes to the knowledge of the genetic diversity of Indian representatives of the genus.