Dual nomenclature in organic-walled dinoflagellate cysts I: concepts, methods and applications

Abstract

Dual nomenclature in dinoflagellates is supported under the current nomenclatural code for algae, fungi and plants and allows a fossil-defined (usually cyst) species to bear a name other than that of its equivalent non-fossil species, as established for example by incubation experiments. Two names can then apply to the same cyst morphotype, reflecting the separate but overlapping concepts and criteria used for fossil- and non-fossil taxa. Fossil-species are normally and logically assigned to fossil-genera and non-fossil species to non-fossil genera, a practice that facilitates dual nomenclature. Inconsistencies and ambiguities arise when binomials combine the names of fossil- with non-fossil taxa. Examples of this hybridised nomenclature and its consequences are examined, with problems identified and potential solutions discussed. Accordingly, a new non-fossil genus Lingulaulax is proposed with Lingulaulax polyedra (von Stein 1883) comb. nov. as its type and equivalent to the fossil-species Lingulodinium machaerophorum (Deflandre & Cookson 1955) Wall 1967, along with the new combination Lingulaulax milneri (Murray & Whitting 1899); the genus Lingulodinium Wall 1967 is retained in its exclusively fossil status. The non-fossil name Gonyaulax ellegaardiae Mertens et al. 2015 is validly published herein.

Keywords:

• Dinocyst
• taxonomy
• dual nomenclature
• hybridised names
• Lingulodinium
• Lingulaulax

Acknowledgements

Haifeng Gu is thanked for providing the basis for Figure 4. MJH acknowledges support from a Natural Sciences and Engineering Research Council of Canada Discovery Grant. KNM was financially supported by the French National Research Agency (ANR) PhenoMap project, ANR-20-CE02-0025. RAF acknowledges the support of Natural Resources Canada; this is NRCan contribution number 20230058. We are most grateful to P.J. Mudie and the four journal reviewers, including V. Pospelova, all of whom provided helpful comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Martin J. Head

MARTIN J. HEAD is a professor of Earth sciences at Brock University. His interests are in late Cenozoic marine palynology, and particularly the late Neogene–Quaternary record of dinoflagellate cysts and acritarchs and their application to palaeoenvironmental reconstruction. He is also involved in formal chronostratigraphy including that of the Quaternary Period. He is a former president of AASP – The Palynological Society and of the Canadian Association of Palynologists.

Kenneth N. Mertens

KENNETH NEIL MERTENS is a researcher at Ifremer, LER BO, Concarneau, France. He received his PhD in 2009 from Ghent University. His research interests are the taxonomy, evolution, phylogeny and biogeography of dinoflagellates, and the palaeoceanographical application of dinoflagellate cysts, particularly in the Quaternary and Neogene.

Robert A. Fensome

ROBERT A. FENSOME is a research scientist with the Geological Survey of Canada (GSC), part of the federal department of Natural Resources Canada, in their Atlantic Division at the Bedford Institute of Oceanography, Dartmouth, Nova Scotia. During his 39-year tenure at the GSC, he has focussed mainly on Mesozoic and Cenozoic dinoflagellate cysts from offshore eastern Canada, but recently ventured into projects involving assemblages from north-western and Arctic Canada. While his mandate has involved primarily biostratigraphical and palaeoenvironmental studies, he also has a strong interest in dinoflagellate taxonomy and evolution, miospore taxonomy and geological outreach, and has co-authored and co-edited two books for a general audience, one on the geology of Canada and one on the geology of Canada’s Maritime Provinces.