The manuscript of Corsaro et al. had been withdrawn from the list of accepted manuscripts due to the lack of taxonomic accuracy on the description of the species proposed. In the light of the results the new species cannot be considered as a /Candidatus/ taxon until their members have been isolated as pure cultures in the laboratory. The manuscript was withdrawn in order to emend the incorrect description of a taxon that cannot be validated due to the lack of cultured members. This article has been retracted consistent with Elsevier Policy on Article Withdrawal. Please see . The Publisher apologizes for any inconvenience this may cause.