Morphology, ecology and biogeography of Stauroneis pachycephala P.T. Cleve (Bacillariophyta) and its transfer to the genus Envekadea

Stauroneis pachycephala was described in 1881 fromthe Baakens River, Port Elizabeth, South Africa. Recently, it was found during surveys of the MacKenzie River (Victoria, Australia), the Florida Everglades (USA) and coastal marshes of Louisiana (USA). The morphology, ecology and geographic distribut...

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Bibliographic Details
Published in:Diatom Research
Main Authors: Atazadeh, I., Edlund, M., Van der Vijver, B., Mills, K., Spaulding, S., Gell, P., Crawford, S., Barton, A., Lee, S., Smith, K., Newall, P., Potapova, M.
Format: Article in Journal/Newspaper
Language:English
Published: Taylor & Francis 2014
Subjects:
diatoms
morphology
Stauroneis pachycephala
ecology
Envekadea
biogeography
taxonomy
lectotype
Mackenzie River
Mackenzie river
Online Access:http://hdl.handle.net/2440/96747
https://doi.org/10.1080/0269249X.2014.927006
Description
Summary:Stauroneis pachycephala was described in 1881 fromthe Baakens River, Port Elizabeth, South Africa. Recently, it was found during surveys of the MacKenzie River (Victoria, Australia), the Florida Everglades (USA) and coastal marshes of Louisiana (USA). The morphology, ecology and geographic distribution of this species are described in this article. This naviculoid species is characterised by lanceolate valves with a gibbous centre, a sigmoid raphe, an axial area narrowing toward the valve ends, and capitate valve apices. The central area is a distinct stauros that is slightly widened near the valve margin. The raphe is straight and filiform, and the terminal raphe fissures are strongly deflected in opposite directions. Striae are fine and radiate in the middle of the valve, becoming parallel and eventually convergent toward the valve ends. The external surface of the valves and copulae is smooth and lacks ornamentation. We also examined the type material of S. pachycephala. Our observations show this species has morphological characteristics that fit within the genus Envekadea. Therefore, the transfer of S. pachycephala to Envekadea is proposed and a lectotype is designated. Islam Atazadeha, Mark B. Edlundb, Bart Van der Vijvercd, Keely Millsaek, Sarah A. Spauldingf, Peter A. Gella, Simon Crawfordg, Andrew F. Bartona, Sylvia S. Leeh, Kathryn E.L. Smithi, Peter Newalla, Marina Potapovaj

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