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Updated: Jun 2, 2026
10:14
Reconstructing Terrestrial Paleoclimate and Paleoecology with Fossil Leaves Using Digital Leaf Physiognomy and Leaf Mass Per Area
Published on: October 25, 2024
Fossil evidence for Cretaceous escalation in angiosperm leaf vein evolution
Taylor S Feild1, Timothy J Brodribb, Ari Iglesias
1Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA. hedyosmum@gmail.com
Summary
Flowering plants (angiosperms) evolved significantly higher leaf hydraulic capacities during the Cretaceous period. This escalation in vein density (D(V)) occurred in two phases, lagging behind their initial diversification.
Area of Science:
- Paleobotany
- Plant Physiology
- Evolutionary Biology
Background:
- Modern flowering plants (angiosperms) exhibit superior leaf gas exchange compared to other plant groups.
- This capacity is hypothesized to be a driver of major ecological and biogeochemical changes during the Cretaceous period.
- Empirical evidence linking angiosperm leaf evolution to high photosynthetic activity during the Cretaceous is lacking.
Purpose of the Study:
- To investigate the evolution of leaf hydraulic capacities in fossil angiosperms during the Cretaceous.
- To provide empirical evidence for the timing of angiosperm leaf trait evolution relative to their diversification.
Main Methods:
- Analysis of fossil angiosperm leaf specimens.
- Measurement of fossil leaf vein density (D(V)) as a proxy for leaf hydraulic capacity.
Main Results:
- Early angiosperm leaves had low D(V), similar to coexisting ferns and gymnosperms.
- A biphasic increase in angiosperm D(V) was observed during the Cretaceous.
- Angiosperm D(V) surpassed nonangiosperm limits in the mid-Cretaceous, with modern rainforest tree levels appearing near the Cretaceous-Tertiary boundary.
Conclusions:
- Angiosperm leaf hydraulic capacities significantly increased over several-fold during the Cretaceous.
- The evolution of high-capacity leaves lagged behind the initial taxonomic diversification of angiosperms.
- This suggests a delayed impact of angiosperms on ecosystems despite their early evolutionary success.
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