Morphological variability in Neodenticula seminae, a marine planktonic diatom in the North Pacific Ocean and Bering Sea

Image analysis of the living, marine planktonic diatom, Neodenticula seminae (Simonsen et Kanaya) Akiba et Yanagisawa, collected during summers of 1996-99 off northeast Japan, the Kurile Islands and in the Bering Sea revealed significant intraspecific morphological variability. SEM observations showed the internal valve morphology to be more variable in populations from the northwestern Pacific than in those from the Bering Sea, with the latter having lower variability for almost all morphometrics. In particular, the robustness of the basal ridge in the Bering Sea population was readily apparent, both visually and statistically. This implies that valves from the northwestern Pacific have relatively more delicate basal ridges and larger foramina.