Palynodinium

Palynodinium is an extinct genus of organic-walled dinoflagellate cyst (or dinocyst). It is a fossil species of dinoflagellate cyst used to demarcate the K/Pg boundary, which marks the terminal Cretaceous and the extinction of the dinosaurs.^[1] Palynodinium grallator was among the microfossils which lead to the recent discovery of the K/Pg event record in marine sediments of the northeast Pacific.

Palynodinium
Bright-field photomicrograph of Palynodinium grallator produced by Sandy McLachlan, University of Victoria from the Oyster Bay Formation of eastern Vancouver Island.
Scientific classification
Domain:	Eukaryota
Clade:	Sar
Clade:	Alveolata
Phylum:	Dinoflagellata
Class:	Dinophyceae
Order:	Gonyaulacales
Family:	†Areoligeraceae
Genus:	†Palynodinium H.Gocht, 1970

Dinoflagellate cysts are estimated to be produced by 10–16% of living dinoflagellates^[2][3] as a dormant, zygotic stage of their life cycle, which can accumulate in marine sediments as microfossils. Organic-walled dinoflagellate cysts are noted for their resistance to degradation owing to their composition of dinosporin, a biopolymer similar to sporopolinin characteristic of many terrestrial palynomorphs.^[4][5] Their abundance, cosmopolitan distribution, and quality of preservation in the fossil record since the Middle Triassic^[6][7] make dinoflagellate cysts excellent indicators of primary productivity^[8][9] as well as tools for biostratigraphy and paleoenvironmental reconstructions.^[10][11] The scope of dinoflagellate cyst applications has resulted in ongoing collaborative efforts between industry and academia to refine their taxonomic classification^[12] and enhance their utility through database organization.^[13]