Tropical Species Impacted Worse During KT/K-Pg Extinction

Bivalve network reveals latitudinal selectivity gradient at the end-Cretaceous mass extinction

Authors:

1. Daril A. Vilhena (a)
2. Elisha B. Harris (a,b)
3. Carl T. Bergstrom (a,c)
4. Max E. Maliska (a)
5. Peter D. Ward (a,b,d)
6. Christian A. Sidor (a,b)
7. Caroline A. E. Strömberg (a,b)
8. Gregory P. Wilson (a,b)

Affiliations:

a. Department of Biology, University of Washington, Seattle, WA 98195-1800

b. Burke Museum of Natural History and Culture, University of Washington, Seattle, WA 98195-3010

c. Santa Fe Institute, 1399 Hyde Park Rd., Santa Fe, NM 87501

d. Department of Earth and Space Science, University of Washington, Seattle, WA 98195-1800

Abstract:

Biogeographic patterns of survival help constrain the causal factors responsible for mass extinction. To test whether biogeography influenced end-Cretaceous (K-Pg) extinction patterns, we used a network approach to delimit biogeographic units (BUs) above the species level in a global Maastrichtian database of 329 bivalve genera. Geographic range is thought to buffer taxa from extinction, but the number of BUs a taxon occurred in superseded geographic range as an extinction predictor. Geographically, we found a latitudinal selectivity gradient for geographic range in the K-Pg, such that higher latitude BUs had lower extinction than expected given the geographic ranges of the genera, implying that (i) high latitude BUs were more resistant to extinction, (ii) the intensity of the K-Pg kill mechanism declined with distance from the tropics, or (iii) both. Our results highlight the importance of macroecological structure in constraining causal mechanisms of extinction and estimating extinction risk of taxa.