FWF / Chinese Collaboration Project I 3268: “Biodiversity and Evolution of Marine Planktonic Ciliates” – Total Grant amount: € 522.050; Austrian Group € 265.640. Period: 01.04.2017– 31.03.2022

Ciliates are fascinating unicellular organisms of microscopic size (< 1 mm). The dominating ciliate group in the marine plankton are the Oligotrichea, of which approximately 1,000 shell-forming tintinnid species and about 200 naked aloricate species are known. Oligotrichea are an essential component of the marine food web. They feed on bacteria and other unicellular organisms and are preyed upon by small crustaceans, a crucial food source of fish larvae. Many important aspects of these ciliates are, however, still unknown.

In the joint project with Chinese collaboration partners (NSFB project 317 611 330 01), we compared the genetic diversity of Oligotrichea in European and Chinese coastal waters based on DNA sequence data. We discovered a biodiversity hotspot in Chinese coastal waters and revealed that European and Chinese ciliate communities are quite different. Despite connecting water masses and currents, we could detect dispersal limitations for several groups, which included many currently unknown oligotrichean species. We further contrasted geographic patterns in marine and freshwater plankton by focussing on an ecologically important group of lake ciliates. Genetic traces of these species, which again included unknown ones, were recorded in 252 freshwater lakes in 17 countries worldwide. On the contrary, a comprehensive literature survey suggested a tintinnid species to be endemic to Asian rivers and lakes. In total, we redescribed six ciliate species including tintinnids and established a new tintinnid genus. Based on the latter findings, we could reconstruct the likely appearance of the first tintinnid that lived about 350 Mya.

Further, we developed a user-friendly web-based tool that detects features in DNA sequences characterising particular groups of organisms like the traditionally used morphological features. Thereby, we obtained molecular features of several oligotrichean groups.

The present project could also shed light on further interesting aspects of this ecologically important group of marine planktonic protists by means of transmission electron microscopy, i.e., we reconstructed the evolution of the beautiful and highly elaborate tintinnid loricae, investigated the minute harpoons of tintinnids, and studied for the first time a tintinnid resting cyst.

Link zu   FWF-Projekt I 3268

Project associated publications:

  1. Agatha & Bartel 2022. A comparative ultrastructural study of tintinnid loricae (Alveolata, Ciliophora, Spirotricha) and a hypothesis on their evolution. J. Eukaryot. Microbiol., 69: e12877.   https://doi.org/10.1111/jeu.12877
  2. Agatha, Ganser & Santoferrara 2021. The importance of type species and their correct identification: A key example from tintinnid ciliates (Alveolata, Ciliophora, Spirotricha). J. Eukaryot. Microbiol., 68: e12865.  https://doi.org/10.1111/jeu.12865
  3. Agatha, Gruber, Bartel & Weißenbacher 2022. Somatic infraciliature in tintinnid ciliates (Alveolata, Ciliophora, Spirotricha): an ultrastructural comparison. J. Eukaryot. Microbiol., 69: e12885.   https://doi.org/10.1111/jeu.12885
  4. Agatha, Utz, Zufall & Warren 2021. Symposium on ciliates in memory of Denis Lynn. J. Protistol., 78: 125694.   https://doi.org/10.1016/j.ejop.2020.125694
  5. Frantal, Agatha, Beisser, Boenigk, Darienko, Dirren-Pitsch, Filker, Gruber, Kammerlander, Nachbaur, Scheffel, Stoeck, Qian, Weißenbacher, Pröschold & Sonntag 2022. Molecular data reveal a cryptic diversity in the genus Urotricha (Alveolata, Ciliophora, Prostomatida), a key player in freshwater lakes, with remarks on morphology, food preferences, and distribution. Front. Microbiol., 12: 787290.   https://doi.org/10.3389/fmicb.2021.787290
  6. Ganser & Agatha 2019. Redescription of Antetintinnidium mucicola (Claparède and Lachmann, 1858) nov. gen., nov. comb. (Alveolata, Ciliophora, Tintinnina). J. Eukaryot. Microbiol., 66: 802-820.   https://doi.org/10.1111/jeu.12728
  7. Ganser, Forster, Liu, Lin, Stoeck & Agatha 2021. Genetic diversity in marine planktonic ciliates (Alveolata, Ciliophora) suggests distinct geographical patterns – data from Chinese and European coastal waters. Front. Mar. Sci., 8: 643822.   https://doi.org/10.3389/fmars.2021.643822
  8. Ganser, Santoferrara & Agatha 2022. Molecular signature characters complement taxonomic diagnoses: A bioinformatic approach exemplified by ciliated protists (Ciliophora, Oligotrichea). Mol. Phylogenet. Evol., 170: 107433.   https://doi.org/10.1016/j.ympev.2022.107433
  9. He, Jiang, Agatha & Pan 2022. Taxonomy and phylogeny of the freshwater tintinnid Tintinnopsis tubuformis Chiang, 1956 (Ciliophora, Oligotrichea) and a proposed synonymization of longa nom. corr. Chiang, 1956. J. Eukaryot. Microbiol.: e12918.   https://doi.org/10.1111/jeu.12918
  10. Hütter, Ganser, Kocher, Halkic, Agatha & Augsten 2020. DeSignate: detecting signature characters in gene sequence alignments for taxon diagnoses. BMC Bioinformatics, 21: 151.   https://doi.org/10.1186/s12859-020-3498-6

 

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