title: Bridging the gap between morphological species and molecular barcodes - Exemplified by loricate choanoflagellates.
abstract: Translating the vast amounts of molecular barcodes from global surveys of microbial eukaryotes into ecological insight depends critically on a well-curated reference database with adequate taxonomic coverage. In this respect, the choanoflagellates resemble other eukaryotic lineages: reasonable coverage at higher taxonomic levels, but missing diversity at the species level. The acanthoecid (loricate) choanoflagellates are well-characterized morphologically, with over 115 species described, but less than 10% with any sequence data. Because lorica shape is species-specific, the acanthoecids represent an opportunity to link morphological with molecular data within a lineage of eukaryotes. To match morphospecies to sequences, we sampled the Kattegat and the Isefjord in Denmark in September 2014 and February 2015. We identified 45 morphospecies and sequenced ribosomal DNA of nine previously unsequenced species, roughly doubling the number of acanthoecid species with sequence data, including the first data representing five genera: Bicosta, Calliacantha, Cosmoeca, Crinolina and Pleurasiga. Our phylogenetic analysis is mainly congruent with morphology-based systematics. Five of the newly sequenced species match a previously unidentified barcode from Tara Oceans, providing access to the global distribution of species isolated from Danish waters. One species, Calliacantha natans, is the second most globally abundant choanoflagellate present in Tara Oceans. Our project translating new ribosomal DNA sequences to distributions of described species on a global scale supports the approach linking morphology to molecular barcodes for microbial eukaryote ecology.
authors.affiliation: Zoological Institute, General Ecology, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany. Electronic address: FNitsche@uni-koeln.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Nitsche
authors.affiliation: National Institute of Aquatic Resources (DTU Aqua), Technical University of Denmark, Jægersborg allé 1, DK-2920 Charlottenlund, Denmark.
authors.forename: Helge Abuldhauge
authors.initials: HA
authors.lastname: Thomsen
authors.affiliation: CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France; Sorbonne Universités, Université Pierre et Marie Curie (UPMC) Paris 06, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, 29680 Roscoff, France.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Richter
mesh_terms: D044822:Biodiversity; D056897:Choanoflagellata / Q000145:classification / Q000166:cytology* / Q000235:genetics*; D058893:DNA Barcoding, Taxonomic; D004275:DNA, Ribosomal / Q000235:genetics; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal
keywords: Acanthoecids; Bicostata; Calliacantha; Crinolina; Diaphanoeca; rDNA