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Ultrastructure and Molecular Phylogenetic Position of Heteronema scaphurum : A Eukaryovorous Euglenid with a Cytoproct
Author(s) -
Breglia Susana A.,
Yubuki Naoji,
Leander Brian S.
Publication year - 2013
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/jeu.12014
Subject(s) - biology , phylogenetic tree , ultrastructure , zooid , phototroph , phylogenetics , flagellum , sponge , zoology , clade , ecology , botany , gene , biochemistry , photosynthesis
Euglenids comprise a distinct clade of flagellates with diverse modes of nutrition, including phagotrophy, osmotrophy and phototrophy. Much of the previous research on euglenids has focused on phototrophic species because of their ecological abundance and significance as indicators for the health of aquatic ecosystems. Although largely understudied, phagotrophic species probably represent the majority of euglenid diversity. Phagotrophic euglenids tend to be either bacterivorous or eukaryovorous and use an elaborate feeding apparatus for capturing prey cells. We characterized the ultrastructure and molecular phylogenetic position of Heteronema scaphurum , a eukaryovorous euglenid collected in freshwater. This species was equipped with a distinct cytoproct through which waste products were eliminated in the form of faecal pellets; a cytoproct has not been reported in any other member of the Euglenida. Heteronema scaphurum also had a novel predatory mode of feeding. The euglenid ensnared and corralled several green algal prey cells (i.e. Chlamydomonas ) with hook‐like flagella covered in mucous before engulfing the bundle of prey cells whole. Molecular phylogenetic analyses inferred from small subunit rDNA sequences placed this species with other eukaryovorous euglenids, which was consistent with ultrastructural features associated with the feeding apparatus, flagellar apparatus, extrusomes, and pellicle.