Wednesday October 9, 2024, 5pm GMT+2

Head, Martin J.¹

Dual nomenclature in organic-walled dinoflagellate cysts: a new concept for the Code

1. Department of Earth Sciences, Brock University, Canada.

For the first time, dual nomenclature in dinoflagellates is to be supported explicitly under the International Code of Nomenclature for algae, fungi and plants: the new Madrid Code to be published in mid-2025 (Head et al., 2024a). Dual nomenclature is underpinned by conceptual and practical considerations. It allows the separate naming of fossil- and non-fossil species even when they are linked to one another by incubation studies and other techniques (Head et al., 2024b, 2024c). It is needed because fossil- and non-fossil taxonomies are based on different stages of the life cycle and cannot be integrated at the generic level. All taxonomists today who study dinoflagellates, whether living or fossil, place their work under the Code. The Shenzhen Code and its predecessors have supported dual nomenclature implicitly with the help of examples, but without clear explanation of what it is and how it works. In Madrid, Spain, in July 2024, the Nomenclature Section of the XX International Botanical Congress approved two new articles for the Code that remove earlier contradictions and introduce dual nomenclature explicitly, drawing on a critical distinction between ‘synonymy’ and the new concept and term ‘taxonomic equivalence’ (Head et al., 2024a). Examples using Lingulodinium machaerophorum (Deflandre & Cookson 1955) Wall 1967 and its taxonomic equivalent Lingulaulax polyedra (von Stein 1883) Head et al. 2024c, and Spiniferites elongatus and Spiniferites membranaceus and their taxonomic equivalents Gonyaulax ovum (Gaarder 1954) Head et al. 2024d and Gonyaulax lewisiae Head et al. 2024d, are discussed, crucially along with the nomenclatural criteria used to distinguish between a fossil and a non-fossil specimen.

References

Head, M.J., Gravendyck, J., Herendeen, P.S., Turland, N.J., 2024a. Dual nomenclature to be supported explicitly in the International Code of Nomenclature for algae, fungi, and plants. Palynology [Publication September–October 2024].

Head, M.J., Fensome, R.A., Mertens, K.N., and Herendeen, P.S., 2024b. Critique of Proposals 258–260 to eliminate contradiction between Articles 11.7 and 11.8 and to equate non-fossil with fossil names of dinophytes for purposes of priority, by Elbrächter & al. (2023), and ensuing recommendations. TAXON, 73(1): 405–407.

Head, M.J., Mertens, K.N., and Fensome, R.A., 2024c. Dual nomenclature in organic-walled dinoflagellate cysts I: concepts, methods and applications. Palynology 48, No. 2, 2290200.

Head, M.J., Mertens, K.N., and Fensome, R.A., 2024d. Dual nomenclature in organic-walled dinoflagellate cysts II: Spiniferites elongatus Reid 1974 and S. membranaceus (Rossignol 1964) Sarjeant 1970, and their equivalent non-fossil species Gonyaulax ovum (Gaarder 1954) comb. nov. and G. lewisiae sp. nov. Palynology 48, No. 2, 2300838.