| 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 |
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.
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]