Validation of the generic name Prescottiella gen. nov. (Desmidiales, Zygnematophyceae): a rare African desmid

Prescottiella sudanensis is a rare, asymmetrical desmid currently known from only a few countries in equatorial Africa. During the present study, P. sudanensis cells were found in water samples from Vogel Pan located in the far north-eastern side of Namibia, thereby expanding the known geographical distribution of the species. The location of the sampling site, which is situated in a direct line halfway between the Makgadikgadi pans and Okavango Delta towards the east (Botswana) and the Etosha pans towards the west (Namibia), suggests that migrating birds are likely vectors spreading desmids from one waterbody to another. In this paper a morphological description (including dimensions) and micrographs of P. sudanensis are presented, and the known geographical distribution of the species is discussed in relation to migration routes of birds. As the genus and species names are invalid according to ICN Art. 40.1, the names are also validated in this paper.