Morphology and ecology of Fragilaria misarelensis sp. nov. (Bacillariophyta), a new diatom species from southwest of Europe

ABSTRACT

A new freshwater diatom species was described from southwest Europe (Portugal), based on morphological and ultrastructural characteristics. Fragilaria misarelensis Almeida, C.Delgado, Novais & S.Blanco is characterised by lanceolate valves, with slightly capitate ends, alternate striae and lacking spines joining adjacent cells, which are solitary. The valve shape of Fragilaria misarelensis, when compared to similar forms, is unique, as revealed by a thorough literature survey of Fragilaria species, geometric morphometry and discriminant analysis. Fragilaria misarelensis sp. nov. was frequent and abundant in central Portugal, in poorly mineralized watercourses under low anthropogenic influence, characterised by neutral pH, low conductivity and high dissolved oxygen concentration. The analysis of type material belonging to similar species, Fragilaria capucina fo. sublanceolata-baikali, F. capucina fo. lanceolata-baikali and F. nevadensis, contributed to improving their characterisation and illustration, also supporting the delimitation of the new Portuguese species. Fragilaria capucina fo. sublanceolata-baikali and F. capucina fo. lanceolata-baikali were considered to differ substantially from F. capucina and raised to species level as Fragilaria sublanceolata-baikali (Flower & D.M.Williams) Novais, C.Delgado & S.Blanco, comb. et stat. nov. and Fragilaria lanceolata-baikali (Flower & D.M.Williams) Novais, C.Delgado & S.Blanco, comb. et stat. nov.

KEYWORDS:

• Diatoms
• Freshwater
• Geometric morphometry
• Taxonomy
• Type material

ACKNOWLEDGEMENTS

We are grateful to David Williams, Jovita Yesilyurt and Pat Sims of the Natural History Museum of London (BM), for receiving us so well on our visit to the museum and for the facilities to work with samples of the collections and bibliography search.

FUNDING

This work was cofunded by the European Union through the European Regional Development Fund, framed in COMPETE 2020 (Operational Programme Competitiveness and Internationalization), through the ICT project (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-007690 and the Alentejo Observation and Prediction Systems–ALOP project (ALT20-03-0145-FEDER-000004), which awarded a postdoc grant to the first author. The Foundation for Science and Technology (FCT, Portugal) granted financial support to GeoBioTec through the UID/GEO/04035/2013 project. The government of Xunta de Galicia (I2C Posdoctoral Fellow–2014) awarded a postdoc grant to the last author. This research received support from the SYNTHESYS Project (http://www.synthesys.info/) titled, “Study and Revision of the Different Type Materials of Fragilaria/Synedra Genera (Bacillariophyceae) and Comparison with Portuguese Taxa” (GB-TAF-3736), financed by European Community Research Infrastructure Action under the FP7 “Capacities” Program.

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Additional information

Funding

This work was funded in great part by National Science Foundation Grant No. 0732233, “Learning Progressions for Scientific Inquiry: A Model Implementation in the Context of Energy.”