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Sellaphoraceae

David G. Mann
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Fallacia frustuleFallacia cellSellaphora valves
taxon links [up-->]Fallacia [up-->]Sellaphora [up-->]Rossia Phylogenetic position of group is uncertain[down<--]Bacillariophycidae Interpreting the tree
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Containing group: Bacillariophycidae

Introduction

This group of benthic raphid diatoms is found world-wide in freshwater and marine epipelon. Until the 1990s, only a few 10s of species had been described and all were classified in Navicula. It is now clear that the family contains many hundreds of species, most of which await names. The genus Sellaphora has become a model system for studying speciation and was the first to be used to explore the possibility of DNA barcoding for diatom identification.

The family Sellaphoraceae was first described in Mereschkowsky in 1902 to contain his new genus Sellaphora, which he separated from Navicula because of its saddle-like plastid. A further genus, Fallacia, was added by Mann (in Round et al. 1990), who also transferred Rossia and Caponea to the Sellaphoraceae. Microcostatus was described by Johansen & Sray (1998), but it is unclear whether this can or should be separated from Fallacia. Some species currently classified in Eolimna may belong in or near Sellaphora, but the type species of Eolimna is a fossil and it is probably impossible to assess whether it belongs to the Sellaphoraceae because of the lack of cytological or molecular data.

Most members of the family have modest dimensions (valve lengths mostly 10–60 µm) and simple shapes.

Characteristics

Discussion of Phylogenetic Relationships

Relationships between Sellaphora, Fallacia and Rossia are not yet clear. Sellaphora species have been studied extensively (using SSU rDNA, ITS rDNA, rbcL and cox1) but there are few sequences from the larger genus Fallacia and only one species of Rossia is commonly encountered.

The genera Caponea, described by Podzorski, and Microcostatus, described by Johansen & Sray (1998), both need further study.

References

Johansen, J.R. & Sray, J.C. (1998). Microcostatus gen. nov., a new aerophilic diatom genus based on Navicula krasskei Hustedt. Diatom Research 13: 93-101.

Title Illustrations
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window
Fallacia frustule
Scientific Name Fallacia
Specimen Condition Dead Specimen
Identified By David G. Mann
Life Cycle Stage Vegetative phase
Body Part frustule
View exterior, SEM
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright © 2008 David G. Mann
Fallacia cell
Scientific Name Fallacia
Specimen Condition Live Specimen
Identified By David G. Mann
Life Cycle Stage Vegetative phase
View valve focus and plastid focus
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright © 2008 David G. Mann
Sellaphora valves
Scientific Name Sellaphora
Creator Frieda Christie
Acknowledgements This micrograph was taken by Frieda Christie, Royal Botanic Garden Edinburgh
Specimen Condition Dead Specimen
Identified By David G. Mann
Life Cycle Stage Vegetative phase
Body Part valves
View exterior and interior of two different species, SEM
Image Use creative commons This media file is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0.
Copyright © 2008 David G. Mann
About This Page

This page is being developed as part of the Tree of Life Web Project Protist Diversity Workshop, co-sponsored by the Canadian Institute for Advanced Research (CIFAR) program in Integrated Microbial Biodiversity and the Tula Foundation.

David G. Mann
Royal Botanic Garden Edinburgh, United Kingdom

Correspondence regarding this page should be directed to David G. Mann at

Page: Tree of Life Sellaphoraceae. Authored by David G. Mann. The TEXT of this page is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Mann, David G. 2010. Sellaphoraceae. Version 07 February 2010 (under construction). http://tolweb.org/Sellaphoraceae/125705/2010.02.07 in The Tree of Life Web Project, http://tolweb.org/

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