A Needle in the Haystack – Mapping Sequences to Morphology Exemplified by the Loricate Choanoflagellate Enibas thessalia sp. nov. (Acanthoecida, Acanthoecidae)

Abstract

Environmental sequencing surveys unveil an unexpected magnitude of protist biodiversity and help to understand environmental community structure as well as biogeographical patterns. The interpretation of these data is still hindered by the lack of a verified and reliable reference database, which is the important basis for all analyses. References should rely on detailed and valid taxonomical descriptions including both morphology and autecological properties. In fact, obtaining such data is still a major challenge as cultivation-based approaches are very selective. In the present study, we highlight the potential to resample habitats which showed phylogenetically interesting sequences from environmental molecular surveys. We have been able to reveal a choanoflagellate species with the use of a single cell isolation approach in order to achieve a morphological description to the target sequence. This new species, Enibas thessalia sp. nov. now extends a recently described monospecific genus. In addition, we illustrate a nudiform lorica reproduction of the genus Enibas by observation of living cells. The genus belongs to the family of Acanthoecidae, which comprises five genera. The morphology of the genus Enibas shows a striking resemblance to the genus Stephanoeca, which belongs to the other family of loricate choanoflagellates, the Stephanoecidae, indicating that morphology alone might not reflect phylogenetic relations. We demonstrate that mapping sequences to a taxonomical description of species is a valuable tool to verify the organism behind an environmental amplicon. We emphasize the urgent need of integrative taxonomy matching molecular data with morphological features to verify the outcome of phylogenetic analyses.