Fossils uncovered in New Mexico’s Jose Creek Formation provide groundbreaking evidence that angiosperms (flowering plants) established dense, fruit-bearing forests around 75 million years ago—9 million years prior to the end-Cretaceous mass extinction that eradicated the dinosaurs. This discovery challenges longstanding evolutionary theories regarding the rise of angiosperms as the dominant plant group on Earth.
Reconstruction of a 74.6 million-year-old Dori tuff flora forest floor showcasing hypothetical angiosperm-dispersal interactions, with plants depicted in life-size forms based on fossil evidence. The mammalian and dinosaur seed dispersers illustrated are based on the known fauna of the Late Cretaceous Campanian period. Image credit: Brian Engh livingrelicproductions.com.
“Our findings reveal that 10 million years before the extinction threshold, angiosperms were amplifying their investment in individual diasporids, forming dense forests in hot, humid environments during the Late Cretaceous,” stated Jaemin Lee, a doctoral student at the University of California, Berkeley.
Flowering plants are believed to have originated during the Early Cretaceous Period, approximately 135 million years ago, initially appearing as small, inconspicuous plants producing tiny seeds that were easily dispersed by the wind.
By the Late Cretaceous, angiosperms had diversified significantly in size, leaves, and flowers, although it was thought that their seed dispersal methods remained unchanged amidst the dominance of dinosaurs.
Contrary to this belief, fossil evidence from Late Cretaceous Doli tuff deposits in the Jose Creek Formation in New Mexico showcases a diverse array of flowering plants, including large-trunked trees from the laurel family and palms, alongside older fern and sequoia lineages.
In stark contrast to other Cretaceous floral patterns, where angiosperms averaged diasporid sizes similar to poppy seeds, the average diasporid size in this fossil forest was comparable to a large blueberry, suggesting an extraordinary increase in volume by more than 100-fold.
“Although it may not seem significant, the larger fruits we consume today are the result of centuries of selective breeding,” remarked Lee.
“For instance, wild watermelons were only 5 cm (2 inches) in diameter.”
“The New Mexico site is unique as it preserves an ancient environment, buried by ash that fell on an inland forest,” added Cindy Louie, a professor at the University of California, Berkeley.
“Unlike most fossil plant sites, which often consist of a mix of materials from various epochs and habitats, this site provides a pure snapshot of a specific moment in time, preserved through rapid ash fall.”
“Ground cover plants remain visible beneath the hardened ash layer, and higher up, leaves that fell during the ash deposit are pointing in all directions.”
“This phenomenon can be likened to a kind of ‘Pompeii for plants,’ where ash deposits meticulously preserve everything in place, allowing researchers to reconstruct forest structures accurately,” explained Lee.
“These deposits carry remnants from the tree canopy to the forest floor, preserving a variety of leaves and flowers.”
“This forest represents the earliest known angiosperm-dominated ecosystem with significantly larger spores and showcases one of the most diverse Cretaceous leaf floras documented to date.”
“The minimized movement within the forest canopy allows for instantaneous preservation, facilitating detailed recreations of these ancient landscapes.”
“This research sheds new light on the complexity of ecological interactions in ancient plant populations that no longer exist.”
For further details, refer to the findings published in the June 25 edition of Science.
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Lee Jae Min et al. 2026. The diversification of reproductive strategies in angiosperms preceded their extinction at the end of the Cretaceous. Science 392 (6805): 1380-1383; doi: 10.1126/science.adw9457
Source: www.sci.news
