Description of a new Pseudostaurosira based on “Fragilaria virescens f. parva” from Erbario Crittogamico Italiano

ABSTRACT

Normally thought of as a cosmopolitan species, Fragilariforma virescens (Ralfs) D.M.Williams & Round has been recorded widely, its occurrence noted in many regional floras. Since its description in 1843, the species has been sub-divided a number of times, yielding over 80+ names of varieties and forms that have been recorded in various printed and online catalogues of diatom names. Some of the names in these catalogues are inadvertent duplicates, or obvious synonyms, etc., but once redundancy is excluded, one must presume that the remaining infra-specific names were invoked to represent some quantifiable deviation from the nominate species – at least as understood on the part of the investigator who created the name. What these names might be, what they might represent, irrespective of the vague nature of the meaning behind many of infra-specific categories, is worth exploring. Resolution might be achieved, to a certain degree at least, by examining any type specimens attached to each of these apparent infra-specific names, should the specimens still be available. Is it worth the effort? Avoiding a direct answer to that question here, one outcome of these kinds of searches, along with discovering new and undocumented taxa, is to throw up various nomenclatural problems. One is highlighted herein.

KEYWORDS:

• Diatoms
• Bacillariophyta
• type material
• SEM
• Pseudostaurosira
• ‘araphid’ diatom

Acknowledgments

We would like to thank the curators at the diatom collections of the Natural History Museum, London for providing the loans of the type materials. We thank Wolf-Henning Kusber and one anonymous reviewer for pertinent corrections on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. In the article, there is some explanation of the area collected: “The mount of San Bernardino is located in the Lepontine Alps and is 2063 meters high; on the mountain, there is a pond called Lago di Mossola from which the river Mossa arose, which bathes the valley of Mirocco. In this valley, at about 1600 m., is the village of San Bernardino where there is the hotel that De Notaris stayed in. Near this hotel are some ponds.”

2. Cuboni wrote: “Fra i manoscritti notarisiani, conservali oggi dalla vedova De Notaris, sig. Antonietta Botto, ho trovato un elenco delle Diatomee che furono appunto raccolte dal De Notaris al San Bernardino in occasione del suo brevissimo soggiorno lassù [Among his manuscripts conserved today by his widow sig. Antonietta Botto, I found a list of diatoms that were collected by De Notaris at San Bernardino on the occasion of his very short stay there” (Cuboni 1887)].

3. Cuccuini, in his detailed account of the entire set, does refer to “Fragilaria virescens Kütz. f. parva” (Cuccuini 1997, 72, 136) – the reference to Kütz. is in error.

Additional information

Funding

Funding was provided in the framework of the DIATOMS project (LIST - Luxembourg Institute of Science and Technology). Some of this research received support from the SYNTHESYS Project http://www.SYNTHESYS.info/which is financed by European Community Research Infrastructure Action under the FP7 Integrating Activities Programme, grant no [FR-TAF-6729].

Notes on contributors

David M. Williams

David M. Williams Contribution: Provision of type material, discussion of results and development of the manuscript.

Carlos E. Wetzel

Carlos E. Wetzel Contribution: LM and SEM analysis, plates, discussion of results and development of the manuscript.