DOI: 10.5061/dryad.fj6q5746d
title: Global factors constrain body size trends across the Great Ordovician Biodiversification Event at a regional scale: a case study from the Arbuckle Mountains of Oklahoma

description: The Great Ordovician Biodiversification Event (GOBE) records a global
 increase in marine biodiversity which reached maximum diversification
 rates during the Middle Ordovician. The degree to which the drivers of the
 GOBE are regional or global is a question which must be addressed through
 analysis of regional data. In this study, stratigraphically constrained
 field-based data from the Middle Ordovician Simpson Group of Oklahoma were
 collected to identify temporal trends in body volume and determine whether
 body volume trends are more closely associated regional or global
 environmental and diversity changes. Volume increase was primarily
 associated with global-scale factors such as age, δ18O (temperature),
 87Sr/86Sr (tectonics), and taxonomic diversity trends; whereas local-scale
 factors of Δ13C (carbon cycle) and lithologic trends were more weakly
 associated with local volume trends. Notably, all factors had a non-zero
 influence over brachiopod volume, indicating that local diversification
 was driven by multifaceted interactions among abiotic and biotic controls.
 These results support the argument that Ordovician diversification
 included a substantial biotic shift during the Middle Ordovician and
 support the hypothesis that global factors were dominant influencing
 diversification patterns during the main phase of the GOBE. This dataset
 includes stratigraphic columns, ltihology, shell measurements, and
 isotopic data used in the analysis.
description: # Global factors constrain body size trends across the Great Ordovician
 Biodiversification Event at a regional scale: a case study from the
 Arbuckle Mountains of Oklahoma Dataset DOI:
 [10.5061/dryad.fj6q5746d](10.5061/dryad.fj6q5746d) ## Description of the
 data and file structure Data include sedimentological data, brachiopod
 shell measurement data, and geochemical data. ### Files and variables
 **AppendixS1.pdf** Stratigraphic columns with lithologic descriptions for
 all outcrops of Simpson Group strata along I-35 in Oklahoma included in
 this analysis. **AppendixS2.csv** Lithologic data collected during field
 work for Simpson Group. Unit ID and formations match stratigraphic columns
 in Appendix 1. **cover and float intervals do not have unit ID #
 **AppendixS3.csv** Brachiopod shell measurement data. Unit ID and
 formations match stratigraphic columns in Appendix 1. The quality of each
 measurement (length & width) was recorded as ‘A,’ ‘B,’ or ‘C’ quality
 according to the following criteria: A: Clear and complete length or width
 measurement, easily identifiable brachiopod; B: Clear measurement, ~80%
 complete length or width exposed; C: Measurement incomplete, but
 brachiopod identifiable. ATD volume = log10(L*W). **AppendixS4.csv**
 Temporal bins for isotope values used in boosted regression analysis with
 value of 87Sr/86Sr, Δ13C, and δ18O per each age interval in Ma. Values for
 each isotope were obtained from published LOWESS curves generated using
 data from Simpson group outcrops. 87Sr/86Sr are from Avila et al. 2022.
 Δ13C are from Edwards and Salzman 2015. δ18O values from Appendix 8.
 **AppendixS5.csv** Age model for time series analysis and boosted
 regression model. Conodont zone and ages from Bauer 1987 and Goldman et
 al. 2020. **AppendixS6.csv** Values used in time series analysis. Sample
 count indicates number of brachiopod shells from which the mean volume and
 the variance of that volume was calculated.  Data for shells in Appendix
 S3. Ages are determined from age model in Appendix S5. **AppendixS7.csv**
 Values used in boosted regression analysis. Data combined from Appendices
 S2, S4, and S6. **AppendixS8.csv** Geochemical data  compiled by Avila et
 al. 2022 used to calculate δ18O LOWESS curve. 18O values compiled by Avila
 et al. 2022 from the following studies:  Edwards et al. 2021,  Grossman
 &  Joachimski 2020, and  Mannik et al. 2021.