Terpsinoe musica Ehrenberg (Bacillariophyceae, centrales), with emphasis on protoplast and cell division

Abstract

The morphology of intact cells ofTerpsinoe musica Ehrenberg and aspects of their morphogenesis have not been described before. Cells attach by apical mucus pads to form long bands; the chloroplast consists of numerous small granules. Formation of the new valvae on cell division starts from a central primary silicification site immediately adjacent to the postmitotic nuclei. The septa mentioned in reference works are erroneous interpretations of freely suspended transverse bars, formed at a later moment than the valvae. The absence of septa, and the presence of a labiate process said to be absent in Terpsinoe americana (Bailey) Ralfs, indicate the necessity of a taxonomic revision of the genus. The features said to distinguishTerpsinoe intermedia Grunow are unstable and cannot be regarded to define a separate entity. No evidence has been found for the euryhaline, brackish and even marine ecology mentioned in the literature forTerpsinoe musica, which typically lives in hardwater springs of (sub)tropical regions. The studies were made on populations collected alive at an interval of over half a century, from the same location.