Observations and lectotypification of Achnanthes gainii (M. Peragallo) A. Mann, a forgotten Antarctic diatom species, with comments on A. bongrainii (M. Peragallo) A. Mann and the Antarctic records of A. groenlandica (Cleve) Grunow
Zidarova, R.; de Haan, M.; Ivanov, P.; Van de Vijver, B. (2026). Observations and lectotypification of Achnanthes gainii (M. Peragallo) A. Mann, a forgotten Antarctic diatom species, with comments on A. bongrainii (M. Peragallo) A. Mann and the Antarctic records of A. groenlandica (Cleve) Grunow. Phytotaxa 759(1): 045-057. https://dx.doi.org/10.11646/phytotaxa.759.1.4
In: Phytotaxa. Magnolia Press: Auckland. ISSN 1179-3155; e-ISSN 1179-3163, more
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| Author keywords |
Achnanthaceae;Achnanthepyla;Bacillariophyta;marine benthos;morphology;South Shetland Islands;taxonomy;benthic diatoms;marine;island;cove;bay |
| Authors | | Top |
- Zidarova, R.
- de Haan, M., more
- Ivanov, P.
- Van de Vijver, B., more
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| Abstract |
Achnanthes gainii, a marine diatom species, was described as Achnanthepyla gainii in 1921 by Maurice Peragallo from Petermann Island (Antarctic Peninsula area). For over a century, this taxon remained solely known from its original description and illustration of a single raphe valve. More detailed observations of the species are lacking, but a literature search showed that during the last century it was transferred to the genus Achnanthes three times. In this paper, we document and illustrate using both light and scanning electron microscope observations, the morphology of valves from a large population from South Bay, Livingston Island (Maritime Antarctica), matching well the description of this historic taxon. Since the search for the original material in the Peragallo Collection in Bordeaux a couple of years ago proved unsuccessful, in the absence of the original material and slides of A. gainii, the original drawing by M. Peragallo in 1921 is designated as lectotype, and the new population from Livingston Island is designated as epitype to the designated lectotype. The species is separated from other similar taxa, including a taxon recently identified as Achnanthes bongrainii, of which observations and scanning electron microscope illustrations are also provided in this work for comparison, based on populations from South Bay. Finally, several researchers previously commented the similarity of A. gainii to Achnanthes groenlandica. Therefore, the Antarctic records of the latter species were also verified, to the extent possible. This resulted in the discovery that a number of the published illustrations of A. groenlandica from Antarctica represent Achnanthes bongrainii, but not A. gainii. |
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