Taxonomic reappraisal of Monostromataceae (Ulvophyceae: Chlorophyta) based on multi-locus phylogeny

Abstract

Monostromataceae have been considered a morphologically discrete group of green algae having thalli made up of a single layer of cells; the family is ubiquitous in intertidal zones of marine and estuarine habitats across the world., However, this view blocks the real complexity of these algae. Using phylogeny reconstruction methods based on five independent molecular data sets (namely, ITS1, ITS2, 5.8S, nrDNA 18S, and rbcL), evolutionary history of this family was inferred for the first time. Results show that monostromatacean algae that have the typical Codiolum-stage sporophyte in the life cycle belong to three clades within Ulotrichales. The present study also suggests that both Ulotrichales and Ulvales are polyphyletic. This report demonstrates for the first time that the 5.8S gene, an often overlooked nucleoribosomal cistron, is a powerful locus for algal phylogeny reconstruction at higher taxonomic levels. ? 2015 ? 2015 Dipartimento di Biologia, Universit? di Firenze.