58 Future Leaders in Paleontology

The Paleontological Society is pleased to offer the “Future Leaders in Paleontology” topical session. This session will showcase the outstanding work of our student and early career members in a high-profile setting.

Sunday, 19 October 2025
1:30 PM - 5:30 PM
HBGCC, 305

Increased polymorphism is associated with heightened extinction across the end-Cretaceous event in cheilostome bryozoans

Paper number: 58-10
Program: Technical Sessions
Time: 3:50 PM – 4:05 PM

Authors

  • Sarah Leventhal Presenting Author
    Smithsonian National Museum of Natural History, Washington, D.C.
  • Stewart Edie
    Smithsonian National Museum of Natural History, Washington, D.C.

Abstract

Division of labor is associated with ecological success in colonial animals such as eusocial insects and bryozoans. Given this association, we might expect division of labor to buffer against extinction during intervals of large scale climatic and environmental change. Here, we compile and analyze a global dataset of fossil colonial animals, cheilostome bryozoans, to test whether division of labor is associated with biotic shifts and extinction across the end-Cretaceous mass extinction (66 Ma). Cheilostome colonies have a wide range of division of labor, reflected by their different body types, termed polymorphs. The pre- and post-extinction biotas of cheilostome bryozoans were not significantly different in their degrees of polymorphism. However, taxa with more polymorph types showed heightened extinction through the end-Cretaceous event. Colony energetics may have played a role in extinction outcomes: colonies with more polymorphism have reduced numbers of feeding in colonies, requiring higher per-capita acquisition of resources. Thus, even typically advantageous traits like division of labor can become liabilities in times of widespread environmental perturbation, revealing how selective regimes can shift rapidly during mass extinction.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-413355

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