Diversity dynamics of Devonian terrestrial palynofloras from China: Regional and global significance

The microfossil-based pattern of the Devonian land plants of China is revised and discussed based on a new, comprehensive dataset. This dataset compiles the chronostratigraphical distribution of 1677 species belonging to 190 genera of spores and pollen from the primary literature, which covers the history of fossil Chinese terrestrial palynofloras. From this, we describe the patterns and biodiversity dynamics using both range-based and sample-based data to illustrate the main fluctuations of Devonian taxonomic richness, including rarefaction by filtering out uneven sampling. Results show that the apparent terrestrial palynofloral diversity of China increases progressively from the Early to Middle Devonian, with a genuine Givetian peak followed by a plateau persisting during the Late Devonian. Results further suggest that sampling effects may strongly influence the perception of biodiversity trends in China, as well as that the observed Late Devonian taxonomic diversification may have been greatly overestimated. Compiled evidence is discussed in the light of the global evolution of marine-terrestrial ecosystems. We hypothesize that the rise of Devonian floras may have played a remarkable role in an oceanic oxygenation event during this Period.