Molecular phylogeny of the Cladophoraceae (Cladophorales, Ulvophyceae), with the resurrection of Acrocladus Nägeli and Willeella Børgesen, and the description of Lurbica gen. nov. and Pseudorhizoclonium gen. nov.

Abstract

The taxonomy of the Cladophoraceae, a large family of filamentous green algae, has been problematic for a long time due to morphological simplicity, parallel evolution, phenotypic plasticity, and unknown distribution ranges. Partial large subunit (LSU) rDNA sequences were generated for 362 isolates, and the analyses of a concatenated dataset consisting of unique LSU and small subunit (SSU) rDNA sequences of 95 specimens greatly clarified the phylogeny of the Cladophoraceae. The phylogenetic reconstructions showed that the three currently accepted genera Chaetomorpha, Cladophora, and Rhizoclonium are polyphyletic. The backbone of the phylogeny is robust and the relationships of the main lineages were inferred with high support, only the phylogenetic position of both Chaetomorpha melagonium and Cladophora rupestris could not be inferred unambiguously. There have been at least three independent switches between branched and unbranched morphologies within the Cladophoraceae. Freshwater environments have been colonized twice independently, namely by the freshwater Cladophora species as well as by several lineages of the Rhizoclonium riparium clade. In an effort to establish monophyletic genera, the genera Acrocladus and Willeella are resurrected and two new genera are described: Pseudorhizoclonium and Lurbica.

Taxonomic Reshuffling of the Cladophoraceae

“…2 in Boedeker et al. ()). It was this well‐supported backbone that allowed the new classification to be built, but in many other algal taxa two markers will not be sufficient to obtain an equally robust phylogeny, especially in poorly known groups for which taxon sampling is sparse (see, for example, a similarly well‐designed study by Fučíková et al.…”

“…The paper of Boedeker et al. () published in this issue represents a milestone in the systematic biology of this widespread group of chlorophytes. The authors propose a new classification of the Cladophoraceae based on a robust molecular phylogeny.…”

“…The study by Boedeker et al. () is an example of good practice in the establishment of a natural classification of a taxonomically difficult group of algae. The authors use sequences of the LSU and SSU rDNA genes obtained from a large number of species to infer a robust molecular phylogeny that is then used to update the classification of the family.…”

“…This is the approach adopted by Boedeker et al. (), and we praise them for being decisive in the face of uncertainty and assigning names to seven monophyletic genera: in addition to redefining Cladophora , Chaetomorpha, and Rhizoclonium , they describe the new genera Lurbica and Pseudorhizoclonium and reinstate Acrocladus and Willeella .…”

Benthic marine algae on Japanese tsunami marine debris – a morphological documentation of the species. Part 3. The green algae and cyanobacteria

“…clade (section Glomeratae) are still under investigation and the taxonomy remains problematic (see Boedeker et al, 2016), we retain C. parriaudii as a genetic variant in C. vagabunda for this study. with oysters for aquaculture.…”