WILLIAMS, D.M. 1990 (May) Distrionella D.M. Williams, nov. gen., a new araphid diatom (Bacillariophyta) genus closely related to Diatoma Bory Arch. Protistenk. 138(2): 171-177, 17 figs. Distrionella n.g. incl. D. asterionelloides n.s. and D. incognita n.c.