Taxonomic reassessment of Polysiphonia foetidissima (Rhodomelaceae, Rhodophyta) and similar species, including P. schneideri, a newly introduced species in Europe

Abstract

Morphological and molecular studies were carried out on two Polysiphonia with 6–9 pericentral cells from the Atlantic Iberian Peninsula. A detailed description is provided for P. foetidissima, a poorly known species originally described from the UK that is widespread and abundant in the Iberian Peninsula. Polysiphonia schneideri, originally described from Atlantic U.S.A. and Bermuda, is reported for the first time in Europe (Southern Spain). It was collected attached to man-made structures such as floating docks and artificial substrata for aquaculture and is believed to be a newly introduced species in Europe. In addition, the taxonomy of seven morphologically similar Polysiphonia was reassessed. A comparative study of type materials showed that the Mediterranean P. stuposa is morphologically different from its alleged synonym P. foetidissima. Instead, molecular and morphological evidence showed that P. foetidissima is a synonym of the widely reported (Atlantic and Pacific) P. tepida. Polysiphonia foetidissima was also shown to differ from P. brodiei, P. exilis, P. isogona and P. schneideri.