• Korean Journal of Environmental Biology
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• v.23 no.4
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• pp.323-327
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• 2005

Two morphologically different species of Peridinium were frequently observed in natural samples collected monthly from Togyo Reservoir. One was previously identified as P. bipes Stein f. occultatum (Lindem.) Lef. (Ki and Han 2005), the other was remained uncertainly so far. We resolved their identity, based on the morphological observations with scanning electron microscopy. The formula of epithecal plate was recorded with 7 precingular, 3 intercalary and 4 apical plates (4', 3a, 7'). An apical pore was apparently present. The conspicuous morphology of the Peridinium was three spines on the hypothecal plates. The average body length and width were $33.6\;{\mu}m$ with a range of $26\~45{\mu}m$, and 25.7 with a range of $19\~31{\mu}m$, respectively; the cell was, therefore, shown slightly elongated. Based on their morphological characteristics, the causative organism was identified as P. aciculiferum (Lemm.), which was reported for the first time in Korean freshwater.

• ALGAE
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• v.23 no.2
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• pp.115-118
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• 2008

Cells of the dinoflagellate Peridinium were frequently observed in water samples of Togyo reservoir, and some species were responsible for dense blooms. Recently, we could identify them as P. bipes f. occultatum Lindem. and P. aciculiferum Lemm., considering morphology (Ki et al. 2005a; Ki and Han 2005b): However, some unidentified Peridinium cells with different shapes and body sizes were found among the samples collected during early spring. Here we describe their morphological characteristics such as thecal plate and body size to characterize its taxonomic identity by morphological characters. The formula of epithecal plates was recorded as 4 apical, 2 intercalary and 7 precingular plates (i.e. 4’', 2a, 7’'’') and the epicone in an apical view was symmetric. An apical pore was easy to make out under a light microscope. No cingular displacement was observed. The average body size was 33 $\mu$m in length with a range of 26-36 $\mu$m, and average 26 $\mu$m in width with a range of 21-31 $\mu$m, respectively; the cell was, therefore, shown slightly elongated. This way we identified Peridinium umbonatum Stein, 1883 for the first time from Korean freshwaters.