Phylogenetic relationships within the tribe Janieae (Corallinales, Rhodophyta) based on molecular and morphological data: a reappraisal of Jania

Abstract

Generic boundaries among the genera Cheilosporum, Haliptilon, and Jania - currently referred to the tribe Janieae (Corallinaceae, Corallinales, Rhodophyta) - were reassessed. Phylogenetic relationships among 42 corallinoidean taxa were determined based on 26 anatomical characters and nuclear small subunit (SSU) rDNA sequence data for 11 species (with two duplicate plants) referred to the tribe Corallineae and 15 species referred to the tribe Janieae (two species of Cheilosporum, seven of Haliptilon, and six of Jania, with five duplicate plants). Results from our 'total evidence' approach were consistent with the hypothesis that the tribe Janieae is monophyletic. Our data indicate, however, that Jania and Haliptilon as currently delimited are not monophyletic, and that Cheilosporum should not be recognized as an independent genus within the Janieae. Our data resolved two well-supported biogeographic clades for the included Janieae, an Indian-Pacific Janieae clade and a temperate North Atlantic Janieae clade. Among anatomical characters, reproductive structures well reflected evolution of the Janieae. Based on our results, three genera, Cheilosporum, Haliptilon and Jania should be merged into a single genus, with Jania having nomenclatural priority. We therefore propose new combinations where necessary of some species previously included in Cheilosporum and Haliptilon.