Abstract
Mallomonas denticulata was described by Matvienko in the 1940s, however the ultrastructure of its scales and bristles remained unknown, so the species was considered to be dubious. Mallomonas asmundiae (≡M. cratis var. asmundiae) is a rather rare and widely accepted species but this name is invalid. In this report we discuss the similarity in the scale and bristle morphology between these two species and designate lectotype and epitype for M. denticulata. An emended description is provided.