Plant taxonomic turnover and diversity across the Cretaceous-Paleogene boundary in northeastern Montana

The Cretaceous-Paleogene (K/Pg) mass extinction was a pivotal event in Earth history, the latest among five mass extinctions that devastated marine and terrestrial life. Whereas much research has focused on the global demise of dominant vertebrate groups, relatively little is known about local scale changes among plant communities across the K/Pg boundary. This study investigates a suite of 11 floral assemblages spanning the K/Pg boundary in northeastern Montana constrained within a well-resolved chronostratigraphic framework. We evaluate the impact of the K/Pg mass extinction on local plant communities as well as the timing of recovery after the mass extinction. Our results indicate that taxonomic richness dropped by ~28% from the Late Cretaceous to Paleocene, a moderate decline compared with other records of plants across the K/Pg boundary. We also find that plant taxonomic composition changed; 63% of latest Cretaceous plant taxa disappeared across the K/Pg boundary, and although coni..., , , # Plant taxonomic turnover and diversity across the Cretaceous-Paleogene boundary in northeastern Montana Supplementary Information

[\[Access this dataset on Dryad\]https://doi.org/10.5061/dryad.n2z34tn4x](https://doi.org/10.5061/dryad.n2z34tn4x)

Please see methods section of manuscript for details on data collection.

## Description of the data and file structure

We have submitted data on our localities and quarries (Table S1), our taxonomic scheme and morphotypes (Table S2), and our raw data (Tables S3-S6), as well as our R script (R Code.R), and supplementary figures as referenced in the manuscript text (Figures S1-S3).

**Supplement - Tables S1-S6.xlsx**: contains supplementary Tables S1 through S6 as described in text

**Table S1:** quarry information

* *UWBM Locality Number*: locality number assigned by University of Washington Burke Museum; unique to each quarry and collection year
* *Locality Name:* locality name as assigned by collector(s)
* *Year:* year in which collection...