Morphology and taxonomy of seven marine sand-dwelling Amphidiniopsis species (Peridiniales, Dinophyceae), including two new species, A. konovalovae sp. nov. and A. striata sp. nov., from the Sea of Japan, Russia

摘要

Seven marine sand-dwelling dinoflagellate species, two of them new and one unidentified, of the genus Amphidiniopsis were recorded in sublittoral sand along the northwestern coast of the Sea of Japan. Their morphological features were examined by light and scanning electron microscopy. Amphidiniopsis konovalovae sp. nov. is dor-soventrally flattened, 36.0-52.5 mu m long, 30.3-45.1 fim wide. The plate formula is APC 4' 2a 7" 4c 5 s 5'" 2"". The thecal plates possess large pores and are ornamented withclosely-spaced small spines. Amphidiniopsis striata sp. nov. is dorsoventrally flattened, 35.2-7.4 mu m long and 28.8-39.8 mu m wide. The plate formula is APC 4' la 7" 4c? 4(5)s 5'" 2"". The thecal plates are ornamented with long longitudinal ridges with large and small pores between them. Intraspecific morphological variability for Amphidiniopsis uroensis and Amphidiniopsis pectinaria has been documented. For A. pectinaria, the left anterior and middle sulcal plates were recorded for the first time, changing the plate formula to: APC 4' 3a 6" 3c 6 s 5"' 2"". For A. rotundata, the middle sulcal plate was shown clearly for the first time. The tabulation of the ventral area of A. arenaria was reinterpreted changing the plate formula to APC 4' 3a 7" 6c 4s 5'" 2"the first precingular plate is now identified as the anterior sulcal plate. A canal plate in the APC was shown for the first time for A. arenaria.