Diversity and morphology of calcareous dinophytes (Thoracosphaeraceae, Peridiniales)

Dinophytes are unicellular eukaryotic algae that, together with
their closest relatives, ciliates and apicomplexans, belong to the
superphylum of alveolates. Some of them, namely calcareous
dinophytes (Thoracosphaeraceae, Peridiniales), develop an immotile
calcareous cell during their life history. They accumulate in the
oceans’ sediments analogously to terrestrial seed banks. Although
the diversity of calcareous dinophytes was investigated in several
studies, only a few of them provide data from coastal waters and
sediments. The main goal of this thesis was to record the diversity
of calcareous dinophytes from marine environments using
morphological, anatomical, taxonomical and evolutionary approaches.
An essential part of the project was to establish living dinophyte
cultures, assuring constant access to fresh material for
morphological and molecular analysis (chapters 1-5). The
morphological diversity of extant species as well as those
described from the fossil record was documented (chapter 1), and
the conflict between molecular and the morphological data was
presented (chapter 1-5). Furthermore, detailed morphological
descriptions of two new species, Scrippsiella bicarinata und S.
kirschiae (chapter 2) and morphological analysis of Bysmatrum sp.,
a species of doubtful phylogenetic position (chapter 4), were
provided. Scrippsiella trochoidea (basionym: Glenodinium
trochoideum), a species with a previously ambiguous description,
has been redescribed and epitypified by myself based on material
collected from the type locality to assure a reliable determination
of this species (Chapter 3). Comparative ultrastructure
investigations using light and electron microscopic techniques at
various stages of the life cycle showed that the anatomical
structure during the biomineralization processes differs within
subgroups of calcareous dinophytes (chapter 5) and could be used as
a useful phylogenetic trait.