International Journal of Systematic and Evolutionary Microbiology, Vol 51, 1581-1586, Copyright © 2001 by Society for General Microbiology

Phylogeny of six naviculoid diatoms based on 18S rDNA sequences

B Beszteri, E Acs, J Makk, G Kovacs, K Marialigeti and KT Kiss
Department of Microbiology, Eotvos Lorand University, Muzeum krt. 4/A., H-1088 Budapest, Hungary

18S rDNA sequences of six Naviculaceae species [Amphora montana, Gomphonema parvulum, Eolimna minima (syn. Navicula minima), Eolimna subminuscula (syn. Navicula subminuscula), Navicula veneta and Phaeodactylum tricornutum] were determined in order to assess the monophyly of this important group of diatoms, to date not included in 18S rDNA databases, and also that of the recently described genus Eolimna. Phylogenetic trees were constructed using other known diatom 18S rDNA sequences, and best tree topologies obtained were tested against alternative trees for their reliability. The analyses do not reject the monophyly of Naviculaceae and strongly support the separation of the genus Eolimna from Navicula sensu lato. The two species of Eolimna, however, do not appear to be each other's closest relatives among the species investigated: rather, E. subminuscula shows affinities to A. montana, and E. minima to P. tricornutum. A. montana, a species which it has been proposed should be transferred into a separate taxon from the other five species, was found to have grouped well within them in all analyses.