'Transformative Sampling' of mounted and already damaged diatom type specimens: A first example using the 'neotype' of Tabellaria fenestrata var. asterionelloides Grunow from Cleve & M?ller's Diatoms (1877-1882)

The 'neotype' of Tabellaria fenestrata var. asterionelloides (BM 12185) has been dam-aged, but the coverslip remains for study. This paper explores the potential of using damaged slides for SEM work to generate more detailed morphological information than previously available, as only LM work was possible with historical specimens. We therefore coin the term 'transformative sampling', by which we mean that a sample is reprocessed to allow for a superior method of analy-sis. Here, specifically, from LM to SEM. In this study, we use slides of Cleve and Moller's no. 75 as an example and give guidelines for processing such samples. As a result of this study, we propose one new name: Asterionella tekelili D.M. Williams, T.M. Schust., E. Cesar & Juttner nom. nov. and clarify the synonymy of Tabellaria flocculosa var. asterionelloides (Grunow) Knudson.