Abstract
A new marine diatom belonging to the genus Auricula was isolated from coastal waters of Ose-zaki (Ose Point) in the Izu Peninsula, Shizuoka Pref., Japan, and is described here as Auricula densestriata sp. nov. The fine structure of the new species has been examined by light and electron microscopy. The species is mainly characterized by the morphological features known to be stable; 1) the radiate striation, with 26-28 in 10 μm; 2) fibulae arranged in a row along the longitudinal costa, their density varying with position in the keel, being 18-24 in 10 um near the central nodule and 7-12 in 10 (im at the keel corner; 3) the girdle bands distinguishable into 4 types mainly on the basis of the structures of the pars media and areolae. The type 3 band is especially distinctive, with a ridge-like pars media extending internally on the ventral arm.