Summary: The manuscript is surely useful and, in principle, it presents a good contribution to the recent methodological trends (polyphasic approach) in cyanobacterial taxonomy, this conclusion should be the main result from this work.
The manuscript of Eckert et al., submitted into the journal Life, concerns in principle again only one, but very important genetic criterion for evaluation of prokaryotic diversity. It should be a serious part of this complex evaluation. It is very important and useful and publication of the article is surely recommendable. However, the connection, coincidences and relations to other criteria should be better expressed.