A new species, Navicula lothargeitleri sp . nov ., within the Navicula cryptocephala complex (Bacillariophyceae)

Recently published phylogenetic analyses of 52 strains of Navicula cryptocephala -like diatoms confirmed the existence of genetically distinct lineages within N . cryptocephala : clade I “RBG” and clade II “Lubnaig”. Using geometric morphometry, we compared strains of both clades with the lectotype and found that clade I represents N . cryptocephala sensu stricto, while clade II constitutes a different taxon, for which we establish a new species, Navicula lothargeitleri sp . nov . Both species can be distinguished by their interphase nucleus structure. Slight differences in valve morphology are described and discussed.