Chlorococcum turfosum comb. nov. (Volvocales, Chlorophyceae) and visualization of chimeric sequences

SUMMARY Parachlorococcum turfosum was previously described based on morphological studies of a culture collection strain originally identified as ‘ Chlorococcum elkhartiense ’ and on an 18S r RNA gene phylogeny of a strain derived from the same original strain but from a different culture collection. However, a subsequently published 18S r RNA gene sequence was inconsistent with the original sequence. Therefore, a new 18S r RNA gene sequence was obtained from the strain from which the holotype was derived. Comparative analyses of the new sequence using the basic local alignment search tool and a newly written Perl code, ChimViewP, which visualizes nucleotide signature shifts characteristic of chimeric sequences, revealed that the sequence used in the original description was of a chimeric nature. Similar analyses also indicated that two published ‘ Chlamydomonas acidophila ’ sequences are chimeric. Phylogenetic analyses excluding all putative chimeras showed that P. turfosum belongs to Chlorococcum , and thus Chlorococcum turfosum comb. nov. is proposed.