A six-gene phylogeny provides new insights into choanoflagellate evolution

• Published in: Molecular phylogenetics and evolution 2017-02, Vol.107, p.166-178
• Main Authors: Carr, Martin, Richter, Daniel J., Fozouni, Parinaz, Smith, Timothy J., Jeuck, Alexandra, Leadbeater, Barry S.C., Nitsche, Frank
• Format: Article
• Language: English
• Subjects: Animals; Biodiversity; Choanoflagellata - classification; Choanoflagellata - genetics; Choanoflagellates; Craspedida; DNA, Ribosomal - genetics; Evolution, Molecular; Fresh Water; Genes, Protozoan; Genome evolution; Holozoa; Life Sciences; Likelihood Functions; Microbiology and Parasitology; Molecular phylogeny; Phylogeny; Protistology; Seawater; Species Specificity; Taxonomic revision
• ISSN: 1055-7903; 1095-9513
• DOI: 10.1016/j.ympev.2016.10.011

[Display omitted] •We have revised, and clarified discrepancies, in the taxonomy of choanoflagellates.•We have erected four new genera and amended two polyphyletic genera.•Choanoflagellate morphology and ecology is examined with a 47-species phylogeny.•The evolution of two translation GTPases is reconstructed using transcriptome data. Recent studies have shown that molecular phylogenies of the choanoflagellates (Class Choanoflagellatea) are in disagreement with their traditional taxonomy, based on morphology, and that Choanoflagellatea requires considerable taxonomic revision. Furthermore, phylogenies suggest that the morphological and ecological evolution of the group is more complex than has previously been recognized. Here we address the taxonomy of the major choanoflagellate order Craspedida, by erecting four new genera. The new genera are shown to be morphologically, ecologically and phylogenetically distinct from other choanoflagellate taxa. Furthermore, we name five novel craspedid species, as well as formally describe ten species that have been shown to be either misidentified or require taxonomic revision. Our revised phylogeny, including 18 new species and sequence data for two additional genes, provides insights into the morphological and ecological evolution of the choanoflagellates. We examine the distribution within choanoflagellates of these two additional genes, EF-1A and EFL, closely related translation GTPases which are required for protein synthesis. Mapping the presence and absence of these genes onto the phylogeny highlights multiple events of gene loss within the choanoflagellates.