Three New Diatom Species from Spring Habitats in the Northern Apennines (Emilia-Romagna, Italy)

Using light (LM, including plastid characterization on fresh material) and scanning electron microscopy (SEM), as well a thorough morphological, physical, chemical, biological of the habitats, present study aims at describing three species new to science. They belong genera Eunotia Ehrenb., Planothidium Round L. Bukht., Delicatophycus M.J. Wynne, were found in two contrasting spring types northern Apennines. The described differ morphologically from most similar by: less dense striae areolae, absence ridge valve face-mantle transition (SEM feature) [Eunotia crassiminor Lange-Bert. et Cantonati sp. nov.; closest established species: minor (Kütz.) Grunow]; narrower shorter cells [Planothidium angustilanceolatum lanceolatum (Bréb. ex Kütz.) Lange-Bert.]; barely-dorsiventral symmetry, set off ends, lower density central dorsal [Delicatophycus crassiminutus minutus M.J.Wynne]. Two we are separated by dimensions. Their description improved knowledge taxa (Eunotia s.l. s.l.) likely be only partially resolved complexes. We could also refine ecological profiles newly-described species. nov., compared minor, appears occur colder inland waters with circumneutral pH strict oligotrophy respect nitrogen. typical habitat nov. oligotrophic mountain flowing springs low conductivity. was observed limestone-precipitating springs, is therefore restricted hard water comparable habitats where CO2 degassing leads carbonate precipitation. Springs unique but severely threatened wetland type. Therefore, in-depth taxonomy ecology characteristic diatom important, because diatoms excellent indicators quality integrity these peculiar ecosystems face direct indirect human impacts.