Dinastridium verrucosum Baumeister from Bavaria (Germany) is a Borghiellacean Dinophyte (†Suessiales).

Phytodinialean dinophytes are poorly known at present and their phylogenetic relationships largely elusive. Historical names of microscopic species are frequently ambiguous, and a reliable application is impeded although crucial to fully explore the biology of organisms. We collected material close to the type locality of a historical species, namely Dinastridium verrucosum, and established eight strains for morphological and molecular studies. The motile cells showed an obovate shape in outline and were dorso-ventrally slightly flattened. They were orange-brown in colour and had a descending cingulum. In light microscopy, an eyespot was discerned in a few monadoid cells in the central region of the sulcus. Furthermore, a morphologically characteristic, 4-6μm long apical furrow was observed on the episome of the cells in SEM. Older cultivated material further exhibited coccoid cells of irregular shape, with wart-like protuberances and covered by a more or less extensive mucilage. This morphology is indistinguishable from the lectotype of D. verrucosum. In a molecular phylogeny, the species was placed in the Borghiellaceae (†Suessiales). As taxonomic result, we epitypify the historical name, D. verrucosum, and perform the necessary combination to Borghiella.