TY - JOUR

T1 - Valvaeodinium hymenosynypha (Morbey) comb. nov., a dinoflagellate cyst from the uppermost Triassic and lowermost Jurassic (Rhaetian and Hettangian) of Europe

AU - Lindström, Sofie

PY - 2023

Y1 - 2023

N2 - Cymatiosphaera hymenosynypha Morbey 1975, previously recorded from the Rhaetian Westbury Formation in the United Kingdom occurs in Triassic–Jurassic boundary strata from Denmark. From the present study it is clear, that this small, finely reticulate, ellipsoidal, two-layered palynomorph is not a prasinophyte, but a dinoflagellate cyst with a combination apical/intercalary archaeopyle (type tAtI) which involves at three apical plates plus one intercalary plate. This cavate cyst is morphologically similar, but not identical to Valvaeodinium hanneae Piasecki 2001 from the uppermost Bathonian to lower Callovian of East Greenland, and it is therefore here transferred to Valvaeodinium, as Valvaeodinium hymenosynypha (Morbey) Lindström comb. nov. The appearance of Valvaeodinium hymenosynypha in Rhaetian strata in the Danish Basin suggests that the lineage of cavate Valvaeodinium cysts originated in the Late Triassic alongside a chorate species of the genus. Valvaeodinium hymenosynypha seems to have just barely survived the end-Triassic mass extinction as it is also present in the earliest Hettangian.

AB - Cymatiosphaera hymenosynypha Morbey 1975, previously recorded from the Rhaetian Westbury Formation in the United Kingdom occurs in Triassic–Jurassic boundary strata from Denmark. From the present study it is clear, that this small, finely reticulate, ellipsoidal, two-layered palynomorph is not a prasinophyte, but a dinoflagellate cyst with a combination apical/intercalary archaeopyle (type tAtI) which involves at three apical plates plus one intercalary plate. This cavate cyst is morphologically similar, but not identical to Valvaeodinium hanneae Piasecki 2001 from the uppermost Bathonian to lower Callovian of East Greenland, and it is therefore here transferred to Valvaeodinium, as Valvaeodinium hymenosynypha (Morbey) Lindström comb. nov. The appearance of Valvaeodinium hymenosynypha in Rhaetian strata in the Danish Basin suggests that the lineage of cavate Valvaeodinium cysts originated in the Late Triassic alongside a chorate species of the genus. Valvaeodinium hymenosynypha seems to have just barely survived the end-Triassic mass extinction as it is also present in the earliest Hettangian.

KW - Faculty of Science

KW - Dinoflagellate cyst

KW - Triassic

KW - Jurassic

KW - Rhaetian

KW - Hettangian

KW - taxonomy

KW - mass extinction

U2 - 10.1080/01916122.2023.2252482

DO - 10.1080/01916122.2023.2252482

M3 - Journal article

VL - 47

JO - Palynology

JF - Palynology

SN - 0191-6122

IS - 4

M1 - 2252482

ER -