Pleurosigma hinzianum sp. nov. and P. frenguellianum sp. nov. (Pleurosigmataceae,Bacillariophyta) from Argentinean coastal waters,in comparison with P. amara Stidolph and P. elongatum W. Smith |
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Authors: | Eugenia A Sar Frithjof AS Sterrenburg Inés Sunesen |
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Institution: | 1. División Ficología Dr. Sebastián A. Guarrera, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina;2. Stationsweg 158, 1852LN Heiloo, the Netherlands |
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Abstract: | Two new marine diatom species from Argentinean coastal waters, Pleurosigma hinzianum Sterrenburg, Sunesen & Sar, sp. nov. and P. frenguellianum Sunesen, Sterrenburg & Sar, sp. nov., are described. The characters permitting their identification are specified, based on comparison with type material of the morphologically similar species P. amara Stidolph and P. elongatum W. Smith in the light (LM) and scanning electron microscope (SEM). New information on the type material of P. elongatum is presented and its taxonomic concept is emended. The main criteria for separation of the species discussed here are: valve outline, path of the raphe-sternum, raphe angle and angle of intersection of the oblique striae in LM; and external central and terminal raphe fissures, internal details of the central area, external and internal apical structure, and morphology of the hymen-occluded internal pores in SEM. The occurrence of these (and probably other) species in the genus Pleurosigma in net samples is adventitious and not indicative of a true planktonic mode of life. |
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Keywords: | fine morphology Pleurosigma amara P elongatum P hinzianum sp nov P frenguellianum sp nov taxonomy type material |
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