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surrounding the pseudostomal aperture. All trees generated using three nuclear rDNA datasets (18S rDNA, 28S rDNA, and the concatenated 18S + 28S rDNA) demonstrated that three photo-synthetic Paulinella species congruently formed a monophyletic group with robust bootstrap and Bayesian supports (>99% RAxML and 1.0 Baye-sian support), but their relationships remained unresolved within the clade in all trees. The P. longichromatophora, nevertheless, clustered consistently together with Paulinella strain FK01, but with very poor supported. Phylogenetic analyses inferred from plastid-encoded 16S rDNA and the concatenated dataset of plastid 16S+23S rDNA demonstrated that chromatophores of all photosynthetic Paulinella species formed a mono-phyly and fell within cyanobacteria clade with a close relationship to a-cyanobacterial clade containing Prochlorococcus and Synechococcus species with very robust supports of 100% bootstraps and 1.0 Bayesian posterior probabilities. Additionally, phylogenetic analyses of nuclear 18S rDNA and plastid 16S rDNA showed divergent evolution within the photosynthetic Paulinella population after a single acquisition of the chromatophore. After the single acquisition of the chromatophore, ancestral photosynthetic Paulinella appears to diverge into at least two distinct clades, one containing marine P. longichromatophora and freshwater Paulinella strain FK01, the other P. chromatophora CCAC 0185.
PREY SPECIFICITY AND MOLECULAR PHY-LOGENY OF THE THECATE MIXOTROPHIC DINOFLAGELLATE FRAGILIDIUM MEXI-CANUM
Kim S.1, Park M.G.2
1 - Department of Oceanography, Pukyong National University, Busan, Republic of Korea
2 - Department ofOceanography, Chonnam National University, Gwangju, Republic of Korea [email protected]
Feeding mechanism and prey specificity of the mixotrophic thecate dinoflagellate Fragilidium mexicanum (strain Fm-LOHABE01) were examined using the culture isolated from Masan Bay, Korea in 2011 during summer blooms of the toxic dinoflagellate Alexandrium pacificum. We also used novel 18S and 28S rDNA sequences for F. mexicanum to explore inter-species relationships within the genus Fragilidium and to examine its phylogenetic relationships with morphologically similar species (Alexandrium, Goniodoma, and Pyrophacus). F. mexicanum (strain Fm-LOHABE01) fed on species belonging to three dinoflagellate genera (i.e. Alexandrium, Ceratium, and Heterocapsa) when
separately offered a variety of prey including dino-flagellates, raphidophytes, cryptophytes, and a ci-liate. In addition, F. mexicanum displayed different levels of specificity for species of Alexandrium. While F. mexicanum consistently fed on A. fundyense and A. pacificum, feeding on A. affine was observed only once. F. mexicanum ingested prey by direct engulfment through the sulcus, after capturing the prey by a tow filament. Phylogenetic analyses of 18S and 28S rDNA datasets demonstrated that Fragilidium sequences formed a monophyletic group with high statistical supports and diverged into four distinct clades. The first clade consisted of seven F. cf. duplocampanaeforme strains, F. subglobosum from New Zealand, and an unidentified Fragilidium sp. from Florida, USA. The second clade branched as a single sequence for F. subglobosum from Denmark and formed a sister lineage to F. cf. duplocampanaeforme, with weak statistical support. The third clade included Fragilidium sp. EUSK D from Angola, as well as Korean strains of F. mexicanum and F. fissile, and was very strongly supported. The last clade contained the five most divergent sequences of F. subglobosum strains. Further, phylogenetic analyses revealed that the genera Fragilidium and Pyrophacus were sister to a clade that included Alexandrium and Goniodoma. Pyrophacus was a sister to a clade containing members of the genus Fragilidium.
TWO ENIGMATIC GENERA ARE ONE? COMPARISON OF BELONOCYSTISMARINA KLI-MOV, ZLATOGURSKY, 2016 WITH LUFFISPHAERA SPP Klimov V.I.
St.Petersburg State University, Faculty of Biology, Department of Invertebrate Zoology [email protected]
Belonocystis Rainer, 1968 and Luffisphaera Belcher and Swale, 1975 are enigmatic genera, which currently lack supergroup affiliation. The genus Belonocystis was studied mainly on the light-microscopy level, while the genus Luffisphaera was studied only with electron microscopy. Recently provided ultrastructural data on Belonocystis gave an opportunity to compare these taxa using one and the same method. This analysis discovered many similarities in the organization of the cell structure as well as in morphology of the coverings. It was clearly shown that surface structures of Belonocystis represent not a solid capsule, but giant scales, which are similar to those of Luffisphaera. Comparison of the scales has revealed that some Belonocystis species were similar to Luffisphaera species more than inside the genus. Each scale of B. marina was
