Research ArticlePALEONTOLOGY

Little lasting impact of the Paleocene-Eocene Thermal Maximum on shallow marine molluscan faunas

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Science Advances  05 Sep 2018:
Vol. 4, no. 9, eaat5528
DOI: 10.1126/sciadv.aat5528
  • Fig. 1 Richness and turnover patterns derived from resampling pooled taxon occurrences compared to raw values in shell beds bracketing the PETM (dashed line).

    The number of collections in each unit is provided beneath the unit name. (A) Standardized mean species richness for each shell bed ±1 SD for the five sampled horizons through time. Raw richness is depicted in pale gray bars and approximates that presented by Dockery (13, 42). Note difference in scales. (B) Proportion of taxa showing first appearances in a given unit per lineage million years (Lma), standardized for sampling intensity and normalized by duration of intervening time between each shell bed, in comparison to raw, nonnormalized proportions (gray). (C) Same as in (B), for last appearances. OTB, Ostrea thirsae beds; UH, upper Hatchetigbee Formation. Time scale is from Gradstein (60, 61).

  • Fig. 2 Comparisons of species richness versus sample coverage within and among sampled horizons, with 95% confidence intervals.

    Only collections with 10 or more species present were included. Richness values should be compared at the same level of coverage. (A) Pooled occurrence data within each horizon from the synoptic data set. (B) Abundance data for the four best-sampled collections within each of the five sampling horizons.

  • Fig. 3 Ecological structure, using collections with abundance data and taxa coded by ecological guild.

    (A) ANOSIM results comparing ranks of dissimilarities of collection pairs within each of the five horizons against those between horizons (shaded in gray). Width of spindles reflects the number of pairwise comparisons in each, and constriction marks the mean rank for each. (B to D) Proportional representation of individuals coded by (B) trophic strategy, (C) motility, and (D) tiering among pooled collections from each sampled horizon. Error bars represent 95% confidence regions obtained from the 2.5 and 97.5% percentiles of the proportion posterior distributions and are associated with the most represented ecological guild in each plot. PETM is indicated by heavy dashed line. Fac. mobile, facultatively mobile.

  • Fig. 4 Body size and growth data in turritelline gastropods and venericardiine bivalves on either side of the PETM.

    (A) Means ±1 SD and maximum body size for species of turritelline gastropods (top) and venericardiine bivalves (bottom) in each of the five sampled horizons; dashed line denotes the position of the PETM. From left to right, turritelline species are Turritella praecincta (GLM), Turritella multilira, K. mortoni postmortoni, Turritella praecincta, Turritella eurynome (BLM), Haustator gilberti (BM), and H. gilberti (upper Hatchetigbee Formation, UH); venericardiine species are Venericor aposmithii, V. nanaplata, V. pilsbryi (Ostrea thirsae beds OTB), Claibornicardia alticostata, Venericor aposmithii, V. nanaplata, V. pilsbryi (GLM), V. aposmithii (BLM), V. horatiana, V. bashiplata, V. turneri, Venericardia gulielmi (BM), Venericor hatcheplata, and Venericor turneri (UH). (B) Serially sampled δ18O data plotted by distance along the growth axis, revealing annual (seasonal) cycles from two turritelline gastropods in the Paleocene BLM compared to two from the Eocene BM. VPDB, Vienna Pee Dee Belemnite. (C) Same for venericardiine bivalves using both δ18O and δ13C data to help resolve ambiguous annual cycles; our interpretation is indicated by pale vertical bars. Distance axes are the same scale for Paleocene and Eocene shells in each panel, allowing comparison of growth rates (shaded gray bars).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/9/eaat5528/DC1

    Data file S1. Taxonomic data set.

    Data file S2. Ecological classifications.

    Data file S3. Body size data set.

    Data file S4. Stable isotope data set.

    R code S1. Chao

    R code S2. Analysis of similarities

    R code S3. Collection random effects

    Fig. S1. Locality and stratigraphic information.

    Fig. S2. Variation in the proportion of individuals classified as “epifaunal” or “shallow infaunal” plus “deep infaunal” in collections of the five horizons.

    Fig. S3. Ecological structure using synoptic data and taxa coded by ecological guild.

    Fig. S4. Ordination of collections by NMDS of abundance data, with taxa coded by life mode, using Bray-Curtis dissimilarity.

    Fig. S5. Size frequency distributions for five taxa across the PETM.

    Table S1. Twenty-five most abundant mollusk species from collections in the BLM (Paleocene, n = 23) and the BM (Eocene, n = 67) for a comparison of taxonomic similarity across the Paleocene-Eocene boundary.

  • Supplementary Materials

    The PDF file includes:

    • Fig. S1. Locality and stratigraphic information.
    • Fig. S2. Variation in the proportion of individuals classified as “epifaunal” or “shallow infaunal” plus “deep infaunal” in collections of the five horizons.
    • Fig. S3. Ecological structure using synoptic data and taxa coded by ecological guild.
    • Fig. S4. Ordination of collections by NMDS of abundance data, with taxa coded by life mode, using Bray-Curtis dissimilarity.
    • Fig. S5. Size frequency distributions for five taxa across the PETM.
    • Table S1. Twenty-five most abundant mollusk species from collections in the BLM (Paleocene, n = 23) and the BM (Eocene, n = 67) for a comparison of taxonomic similarity across the Paleocene-Eocene boundary.

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    Other Supplementary Material for this manuscript includes the following:

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