DOI: 10.5061/dryad.8kr068k
title: Data from: Aragonite bias exhibits systematic spatial variation in the late Cretaceous Western Interior Seaway, North America

description: Preferential dissolution of the biogenic carbonate polymorph aragonite
 promotes preservational bias in shelly marine faunas. Whilst field studies
 have documented the impact of preferential aragonite dissolution on fossil
 molluscan diversity, its impact on regional and global biodiversity
 metrics is debated. Epicontinental seas are especially prone to conditions
 which both promote and inhibit preferential dissolution, which may result
 in spatially extensive zones with variable preservation. Here we present a
 multi-faceted evaluation of aragonite dissolution within the late
 Cretaceous Western Interior Seaway of North America. Occurrence data of
 molluscs from two time intervals (Cenomanian-Turonian boundary, early
 Campanian) are plotted on new high-resolution paleogeographies to assess
 aragonite preservation within the seaway. Fossil occurrences, diversity
 estimates and sampling probabilities for calcitic and aragonitic fauna
 were compared in zones defined by depth and distance from the seaway
 margins. Apparent range sizes, which could be influenced by differential
 preservation potential of aragonite between separate localities, were also
 compared. Our results are consistent with exacerbated aragonite
 dissolution within specific depth zones for both time slices, with
 aragonitic bivalves additionally showing a statistically significant
 decrease in range size compared to calcitic fauna within
 carbonate-dominated Cenomanian-Turonian strata. However, we are unable to
 conclusively show that aragonite dissolution impacted diversity estimates.
 Therefore, whilst aragonite dissolution is likely to have affected the
 preservation of fauna in specific localities, time averaging and
 instantaneous preservation events preserve regional biodiversity. Our
 results suggest that the spatial expression of taphonomic biases should be
 an important consideration for paleontologists working on
 paleobiogeographic problems.
description: Supplementary
 Information 1Contains information on
 the following items: - Time Intervals - Construction of Paleogeographies -
 Regional Overview and Paleobathymetry Evidence - Fossil Occurrence Dataset
 - Multicollinearity Correlation Tables - Additional Results (Raw
 occurrences, Sampling Probability, Raw Diversity and SQS) - Supplementary
 Figure Captions - Supplementary Table CaptionsSupplementary
 Information 2Excel file with the
 following results, datasets and information: - Cenomanian/Turonian dataset
 - Campanian dataset - Taxonomic Revision - Raw Occurrences - Raw Taxonomic
 Diversity - SQS Estimates of Diversity - Spearman's Rank Correlations
 - Sampling Probability - Multiple Logisitic Regression - Multiple
 Logisitic Regression II - Mineralogy and Life Habits - Mineralogy and Life
 Habits References - Cenomanian/Turonian Range Size - Campanian Range
 SizeSupplementary Table
 1Spearman’s rank
 correlations between species level diversity of faunal groups and various
 sampling proxies for distance-from-paleoshoreline zones within the
 Cenomanian-Turonian and lower Campanian.Table_S1.xlsxSupplementary Figure 1Additional paleogeographic zoned maps of the WIS used in this study Distance based zones are at 50km intervals A. Paleogeographic map of the Cenomanian-Turonian with distance-from-paleoshoreline zones; B. Paleogeographic map of the early Campanian with distance-from-paleoshoreline zones.Fig_S1.pngSupplementary Figure 2Plots of raw occurrences of ammonites, aragonitic and calcitic bivalves, outcrop area and number of collections within depth and distance-from-paleoshoreline zones for the Cenomanian-Turonian and lower Campanian. A. Cenomanian-Turonian occurrences, outcrop area and collections by depth zones, plotted by percentage of total; B. Cenomanian-Turonian occurrences, outcrop area and collections by distance-from-paleoshoreline zones; C. lower Campanian occurrences, outcrop area and collections by depth zones, plotted by percentage of total; D. lower Campanian occurrences, outcrop area and collections by distance-from-paleoshoreline zones.Fig_S2.pngSupplementary Figure 3Plots of sampling probabilities for species level occurrences across depth zones, using Method 2 (see main body of text for further information). A. Cenomanian-Turonian; B. lower Campanian.Fig_S3.pngSupplementary Figure 4Plots of sampling probabilites for species and generic level results for the Cenomanian-Turonian and lower Campanian across distance-from-paleoshoreline zones, using Method 3 (see main body of text for further information). A. sampling probability for species level occurrences across distance-from-paleoshoreline zones for the Cenomanian-Turonian; B. sampling probability for generic level occurrences across distance-from-paleoshoreline zones for the Cenomanian-Turonian; C. sampling probability for species level occurrences across distance-from-paleoshoreline zones for the lower Campanian; D. sampling probability for generic level occurrences across distance-from-paleoshoreline zones for the lower Campanian.Fig_S4.pngSupplementary Figure 5Plots of species level diversity plots for the Cenomanian-Turonian and lower Campanian within depth zones, plotted with number of collections and outcrop area. A. Species diversity and number of collections for the Cenomanian-Turonian; B. Species diversity and number of collections for the lower Campanian; C. Species diversity and outcrop area for the Cenomanian-Turonian; D. Species diversity and outcrop area for the lower Campanian.Fig_S5.pngSupplementary Figure 6Plots of species and generic level diversity plots for the Cenomanian-Turonian and lower Campanian within distance-from-paleoshoreline zones, plotted with number of collections and outcrop area. A. Species diversity and number of collections for the Cenomanian-Turonian; B. Species diversity and number of collections for the lower Campanian; C. Species diversity and outcrop area for the Cenomanian-Turonian; D. Species diversity and outcrop area for the lower Campanian; E. Generic diversity and number of collections for the Cenomanian-Turonian; F. Generic diversity and number of collections for the lower Campanian; G. Generic diversity and outcrop area for the Cenomanian-Turonian; H. Generic diversity and outcrop area for the lower Campanian.Fig_S6.pngSupplementary Figure 7Plots of generic level SQS results for distance-from-paleoshoreline zones for the Cenomanian-Turonian and lower Campanian, set at 0.4, 0.5 and 0.6 quorums. A. SQS results for ammonites in the Cenomanian-Turonian; B. SQS results for ammonites in the lower Campanian; C. SQS results for aragonitic bivalves in the Cenomanian-Turonian; D. SQS results for aragonitic bivalves in the lower Campanian; E. SQS results for calcitic bivalves in the Cenomanian-Turonian; F. SQS results for calcitic bivalves in the lower Campanian.Fig_S7.png