Molecular phylogeny of tribe Myoporeae (Scrophulariaceae) using nuclear ribosomal DNA: Generic relationships and evidence for major clades

Abstract

AbstractEremophila is a significant component of the Australian arid zone flora, but its generic limits and relationships to the other six genera of tribe Myoporeae remain largely untested. In this study, we assembled a dataset of the nuclear ribosomal cistron (ca. 6000 bases including ITS1+2, ETS regions, non‐transcribed spacer and associated genes) for all genera in tribe Myoporeae with a particular focus on Eremophila (205 of total 233 formally described species of Eremophila, and 28 species of related genera sampled). Phylogenetic analyses were performed using maximum likelihood and Bayesian inference methods. These resolved four major clades that were well supported. Eremophila was paraphyletic, with all other genera of tribe Myoporeae nested in it. We discuss two taxonomic options for addressing the paraphyly of Eremophila. As an immediate step, we propose that the small genera, Calamphoreus and Diocirea, should be placed in synonymy under Eremophila, and herein make the necessary new nomenclatural combinations. Additional phylogenetic data are needed, ideally in the form of multiple independent nuclear loci, to clarify the positions of Bontia, Glycocystis and Myoporum relative to Eremophila before further taxonomic changes are proposed.