60-33 Investigating Lifespans of the Genus Glycymeris (Bivalvia) in Deep Time

Session: 2YC and 4YCU Geoscience Student Research Poster Showcase

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Studies of the controls of bivalve longevity in deep time have so far mostly focused on environmental factors. These studies suggest that cool temperatures and seasonal food availability tend to promote longevity through reduction of metabolic rates. While environmental controls are important, other factors such as phylogeny are likely to play a role as well as data from modern organisms suggest a genetic component to longevity. Fossil bivalves represent an ideal avenue from which to understand the role of phylogeny in longevity. The bivalve genus Glycymeris has become a recent target of sclerochronologists working in modern and recent settings because of its well-preserved growth increments, widespread distribution of species, and numerous long-lived taxa. Glycymeris first appeared in North America during the Cretaceous in California and from then and throughout the Cenozoic became a conspicuous component of shallow marine settings across the continent. Previous work found two members of the genus, G. americana and G. subovata to have maximum lifespans of 100 and 33 years respectively. Here, as a preliminary study, we investigate lifespans and growth rates of additional species throughout the Mesozoic and Cenozoic. Our initial results suggest a significant range in lifespans of these taxa: 10 years in G. filosa (Eocene), 16 years in G. staminea (Eocene), 23 years in G. anteparilis (Oligocene), and 54 years in G. parilis (Miocene). Our future plan is to examine lifespans of additional species of this genus and to conduct a phylogenetic analysis from which we can understand how lifespans are distributed across the group.  

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8481

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