Abstract
A new diatom species, Cocconeis cascadensis, is reported from streams in the Southern Cascade Mountain Range in California (USA). Light and scanning electron microscopy reveals morphological novelties related to the structure of the areolae on the sternum valve, which are surrounded externally by crater-like depressions, as well as apically elongated bumps in the submarginal hyaline area of the raphe valve. The valve morphology of the coarsely striated taxa, Cocconeis placentula var. lineata, C. pseudolineata and C. neodiminuta from the studied streams, and C. disculus from freshwaters in Europe, is presented for comparison. The newly described species possesses a unique combination of morphological features, representing an intermediary between the more complex valve ultrastructure of marine Cocconeis taxa and the freshwater members of the C. placentula species complex, with simple slit-like areolae. Cocconeis cascadensis inhabits cold-water mountain streams with low conductivity, low nutrients and low dissolved organic carbon concentrations.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
