Re-evaluation of Cerebropollenites thiergartii Eberh.Schulz 1967 and related taxa: priority of Sciadopityspollenites and nomenclatural novelties

Abstract

The important marker species for the base of the Jurassic, Cerebropollenites thiergartii, occurs contemporaneously with at least nine related taxa. However, their distinction is difficult and has been confused in the past. In addition, a long history of numerous recombinations with different genus names (e.g. Tsugaepollenites and Sciadopityspollenites), and inconsistent classifications or synonymisations, further complicate the taxonomic framework of Cerebropollenites thiergartii. A comprehensive study of these ten taxa, summarising their crucial distinctive characteristics and potential synonymy, is currently missing. This limits the stratigraphic value of Cerebropollenites thiergartii and associated taxa relevant to the Triassic–Jurassic transition. Here, we revisit relevant holotype material, related taxa and investigated new material for potential interspecific and intraspecific morphological variation. Based on an empirical analysis of name use and an extensive literature review, we identified previous sources of confusion, re-evaluated the distinctive characteristics and stratigraphic value of these taxa, and their relevance for the Triassic–Jurassic transition. Finally, we argue that the recombination as Sciadopityspollenites thiergartii is taxonomically and nomenclaturally imperative, not only due to priority, but also because it unifies previous disjunct use of Cerebropollenites for Mesozoic and Sciadopityspollenites for Cenozoic taxa, or Mesozoic species in many Russian studies. Thus, we propose a series of nomenclatural novelties: Sciadopityspollenites emend., Sciadopityspollenites thiergartii comb. nov. et emend., S. thiergartii ssp. nov. thiergartii, S. thiergartii ssp. multiverrucosus stat. nov., S. megaorbicularius sp. nov., S. carlylensis comb. nov. et emend., S. serratus emend., S. macroverrucosus emend., S. mesozoicus emend., Cryptopalynites gen. nov., Cryptopalynites pseudomassulae comb. nov. et emend.