WILLIAMS, David M. 2021 (Jan. 20) Notes on the diatom collection of the Natural History Museum, London (BM) II-IV. Some type specimens in the genus Aulacodiscus Ehrenberg and nomenclatural notes on Thumia Cleve ex F.B. Taylor Phytotaxa 480(2): 152-162, 27 figs., 1 table Aulacodiscus madagascarensis n.s., Thumia gutwinskii n.c.