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Abstract
Identifying and describing biodiversity remains fundamental to developing a proper understanding of ecological and biogeographic processes. In this paper, we describe Pseudostaurosira diablarum Seddon & Witkowski sp. nov., a new diatom (Bacillariophyceae) species discovered from Las Diablas wetlands, a brackish water coastal lagoon on the Galápagos Islands. The taxon was observed in both the surface (i.e., extant) and core (i.e., sub-fossil) material from the lagoon, found on shaded mangrove substrata with salinities between 5.2 and 8 g L−1. These observations were confirmed by estimating the salinity tolerances of core samples from the palaeoecological record using a diatom salinity transfer function. We provide light and electron microscope images of P. diablarum sp. nov. Under the light microscope, the best diagnostic features are its lanceolate–elliptical shape, and the striae which are composed of a single row of areolae and do not occur all the way to the apices. Under the scanning/transmission electron microscope, the most distinctive features are the delicate closing plates which are less articulated and branched than in many of the other members of this genus, in addition to the simple, stunted spines which interrupt the striae on the valve margin. The taxon described here constitutes further evidence that the Diablas wetlands are an important site for diatom research, with the potential to provide insights into the processes resulting in the dispersal and evolution of its diatom species.
Supplemental data
Supplemental Material 1
Salinity curves estimated from the WA transfer function with P. diablarum included (top) and excluded from the calibration dataset. The curves are similar due to the generally low abundance of P. diablarum throughout the\enlargethispage{-3.5pt} record.
Supplemental Material 2
Full nomenclatural names for Figures 27(b/c).
Supplemental data for this article can be accessed here. [link to data]
Acknowledgements
The authors thank Simon Haberle, Iona Flett, Jim Neale, Henk Heijnis, Iain Robertson, Emily Coffey, Benson Schliesser, and Salome Maldonado for their efforts in the field, and the Galápagos National Park for providing the permits for this fieldwork. We also thank Manfred Ruppel (Goethe University, Frankfurt am Main) for the access to SEM and Horst Lange-Bertalot for correcting the Latin.