186 New Approaches to Old Fossil Collections (Posters)

Material collected during the early history of paleontology conserves deep time ecosystems and remains available for study. We invite presentations of new analyses and interpretations of well-studied collections in the context of the broader history of the discipline.

Tuesday, 21 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

An Investigation of Tropical Angiosperm Genome Sizes from the Albian-Cenomanian Une Formation of Colombia

Paper number: 186-6
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Ancestral character estimation suggests that flowering plants downsized their genomes in their early evolutionary history. In living angiosperms, genome size and guard cell length are generally strongly and positively correlated. Genome downsizing likely benefited early angiosperms physiologically and ecologically relative to gymnosperms and ferns, which ancestral character estimation suggests did not downsize their genomes during the Early Cretaceous. However, there are not yet sufficient Early Cretaceous guard cell length data to ground truth ancestral character estimates for Early Cretaceous angiosperm genome sizes and guard cell lengths, especially for tropical angiosperms. We are currently measuring guard cell lengths on abundant angiosperm cuticles from the Albian-Cenomanian Une Formation (Colombia) to infer paleogenome sizes. Our preliminary results show some variation in guard cell lengths among morphotypes, perhaps reflecting differences in ploidy level, repetitive DNA content, or both. Interestingly, our best-sampled morphotype, a eudicot with stomatal rings and reticulate venation, has the smallest guard cell lengths and therefore the smallest inferred genome size. Ultimately, we hope to contextualize our research in the framework of broader trends related to angiosperms’ ecological and evolutionary success.

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

doi: 10.1130/abs/2025AM-412889

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