Phylogenetic position of Ooplanctella planoconvexa, gen. et comb. nova and Echinocoleum elegans (Oocystaceae, Trebouxiophyceae, Chlorophyta)

The coccoid green algae Coenochloris planoconvexa and Echinocoleum elegans are assigned to different families (Radiococcaceae and Oocystaceae, respectively), but display similar ray like mucilaginous envelopes. Molecular analysis of the 18S rRNA gene of C. planoconvexa CAUP H 5502 and E. elegans SAG 37.93 revealed that they both belong to Oocystaceae. However, the two strains were not a part of a monophyletic cluster. Furthermore, their morphology differed, namely in the shape of their mucilaginous envelopes, and in their ability to form four-celled units in a broadened sporangial wall. Because the name Coenochloris cannot be used for members of Oocystaceae, a new genus Ooplanctella, with the type species O. planoconvexa comb. nova, is proposed.