Critical criteria for identification of the genus<i>Chaetoceros</i>(Bacillariophyta) based on setae ultrastructure. I. Subgenus<i>Chaetoceros</i>

Abstract

:To propose identification criteria for Chaetoceros subgenus Chaetoceros based on setae ultrastructure, we sampled 38 Korean coastal water locations and 12 Chukchi Sea, Arctic Ocean sites and we studied 11 species using light microscopy and scanning electron microscopy. We selected seven criteria for species-specific identification: (1) spine form; (2) poroid arrangement; (3) number poroid rows between costae; (4) costae presence or absence; (5) angle of costa against the seta rim; (6) spine cross-sectional shape; and (7) seta wall silicification. On the basis of these criteria, we constructed a flowchart to enable species-specific identification. We showed that similar species within the subgenus Chaetoceros can be distinguished solely on the basis of setae criteria.