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Quantitative biostratigraphical ranges of some late Cenozoic species of the dinoflagellate genusSpiniferitesand taxonomic considerations
Langue
EN
Article de revue
Ce document a été publié dans
Palynology. 2018-12-14, vol. 42, n° sup1, p. 203-220
Résumé en anglais
A new quantitative biostratigraphical method, based on an ‘index of stratigraphical abundance’ (ISA), has
been used to refine the stratigraphical range of 50 dinoflagellate cyst taxa. Most of these correspond to
Quaternary ...Lire la suite >
A new quantitative biostratigraphical method, based on an ‘index of stratigraphical abundance’ (ISA), has
been used to refine the stratigraphical range of 50 dinoflagellate cyst taxa. Most of these correspond to
Quaternary representatives of Achomosphaera or Spiniferites. Some extinct taxa are also discussed when
their morphology is close to that of recent species (e.g. Spiniferites lenzii, S. twistringiensis and S. pseudofurcatus),
as well as some species possibly related to the motile Gonyaulax spinifera complex. The ISAs of
S. mirabilis and S. hyperacanthus are similar, as well as for S. elongatus and S. sphaericum. Although initially
presumed as indicating morphotypes of a same taxon, it seems rather that the ISAs similarites must be
interpreted as an indication of close ecological preferences. The emergence of forms of Spiniferites with
low to absent septa appears relatively late (compared to the range of the genus), but the first occurrence
of intergonal processes is relatively early, indicating that it is probably a character deeply rooted into the
generic genome. The previously calculated phylogeny of some Gonyaulax motile cells shows a different
tree pattern than the stratigraphical first appearance succession of their presumed cyst equivalents.< Réduire
Mots clés en anglais
Biostratigraphy
Dinoflagellates
Gonyaulax spinifera complex
Neogene
Quaternary
Spiniferites