SAME BUT DIFFERENT: TWO NOVEL BICARINATE SPECIES OF EXTANT CALCAREOUS DINOPHYTES (THORACOSPHAERACEAE, PERIDINIALES) FROM THE MEDITERRANEAN SEA

Authors

  • Carmen Zinssmeister,

    1. Fachbereich Geologische Wissenschaften, Fachrichtung Paläontologie, Freie Universität Berlin, Malteserstraße 74-100, D – 12249 Berlin, Germany
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    • Present address: Department Biologie, Systematische Botanik und Mykologie, Ludwig-Maximilians-Universität München, Menzinger Str. 67, D – 80638 München, Germany.

  • Sylvia Soehner,

    1. Fachbereich Geologische Wissenschaften, Fachrichtung Paläontologie, Freie Universität Berlin, Malteserstraße 74-100, D – 12249 Berlin, Germany
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    • Present address: Department Biologie, Systematische Botanik und Mykologie, Ludwig-Maximilians-Universität München, Menzinger Str. 67, D – 80638 München, Germany.

  • Monika Kirsch,

    1. Fachbereich Geowissenschaften – Fachrichtung Historische Geologie/Paläontologie, Universität Bremen, Klagenfurter Straße, D – 28359 Bremen, Germany
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  • Eva Facher,

    1. Department Biologie, Systematische Botanik und Mykologie, Ludwig-Maximilians-Universität München, Menzinger Str. 67, D – 80638 München, Germany
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  • K. J. Sebastian Meier,

    1. Institut für Geowissenschaften, Christian-Albrechts-Universität zu Kiel, Ludewig-Meyn-Str. 10, D – 24118 Kiel, Germany
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  • Helmut Keupp,

    1. Fachbereich Geologische Wissenschaften, Fachrichtung Paläontologie, Freie Universität Berlin, Malteserstraße 74-100, D – 12249 Berlin, Germany
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  • and Marc Gottschling

    1. Department Biologie, Systematische Botanik und Mykologie, GeoBio-Center, Ludwig-Maximilians-Universität München, Menzinger Str. 67, D – 80638 München, Germany
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  • Received 3 August 2011. Accepted 13 March 2012.

Abstract

The diversity of extant calcareous dinophytes (Thoracosphaeraceae, Dinophyceae) is currently not sufficiently recorded. The majority of their coccoid stages are cryptotabulate or entirely atabulate, whereas relatively few forms exhibit at least some degree of tabulation more than the archeopyle. A survey of coastal surface sediment samples from the Mediterranean Sea resulted in the isolation and cultivation of several strains of calcareous dinophytes showing a prominent tabulation. We investigated the morphologies of the thecate and the coccoid cells and conducted phylogenetic analyses using Maximum Likelihood and Bayesian approaches. The coccoid cells showed a distinct reflection of the cingulum (and were thus cingulotabulate), whereas thecal morphology corresponded to the widely distributed and species-rich Scrippsiella. As inferred from molecular sequence data (including 81 new GenBank entries), the strains belonged to the Scrippsiella sensu lato clade of the Thoracosphaeraceae and represented two distinct species. Morphological details likewise indicated two distinct species with previously unknown coccoid cells that we describe here as new, namely S. bicarinata spec. nov. and S. kirschiae spec. nov. Cingulotabulation results from the fusion of processes representing the pre- and postcingular plate series in S. bicarinata, whereas the ridges represent sutures between the cingulum and the pre- and postcingular series in S. kirschiae, respectively. Bicarinate cingulotabulation appears homoplasious among calcareous dinophytes, which is further supported by a comparison to similar, but only distantly related fossil forms.

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