Document Type
Article
Publication Date
4-1-2022
Publication Title
Science Advances
Abstract
All skeletal marine invertebrate phyla appeared during the Cambrian explosion, except for Bryozoa with mineralized skeletons, which first appear in the Early Ordovician. However, the skeletal diversity of Early Ordovician bryozoans suggests a preceding interval of diversification. We report a possible earliest occurrence of palaeostomate bryozoans in limestones of the Cambrian Age 4 Harkless Formation, western United States. Following recent interpretations of the early Cambrian Protomelission as a soft-bodied bryozoan, our findings add to the evidence of early Cambrian roots for the Bryozoa. The Harkless fossils resemble some esthonioporate and cystoporate bryozoans, showing a radiating pattern of densely packed tubes of the same diameter and cross-sectional shape. Further, they show partitioning of new individuals from parent tubes through the formation of a separate wall, a characteristic of interzooecial budding in bryozoans. If confirmed as bryozoans, these fossils would push back the appearance of mineralized skeletons in this phylum by ~30 million years and impact interpretations of their evolution.
Volume
8
Issue
16
DOI
10.1126/sciadv.abm8465
Recommended Citation
Pruss, Sara B.; Leeser, Lexie; Smith, Emily F.; Zhuravlev, Andrey Yu; and Taylor, Paul D., "The Oldest Mineralized Bryozoan? A Possible Palaeostomate in the Lower Cambrian of Nevada, USA" (2022). Geosciences: Faculty Publications, Smith College, Northampton, MA.
https://scholarworks.smith.edu/geo_facpubs/168
Comments
Archived as published. Open access article.