Fleshy Fruits from 75 Million Years Ago Suggest Dinosaurs Aided Seed Dispersal

A study published June 25 in Science reveals that flowering plants (angiosperms) produced large, fleshy fruits nearly 75 million years ago—10 million years earlier than previously thought. Researchers analyzed 77 types of fossilized diaspores (fruits and seeds) from the Jose Creek Formation in south-central New Mexico, preserved in a 0.75-mile-long ash layer called Dori's tuff from a volcanic eruption 74.6 million years ago. Of these, 34% were fleshy, indicating they were likely eaten by herbivorous dinosaurs and other animals for seed dispersal. The fossils, about the size of a blueberry or large acorn, challenge the long-held narrative that large fruits evolved only after the Chicxulub impact wiped out non-avian dinosaurs 66 million years ago, when fruit-eating mammals diversified. Lead author Jaemin Lee, a paleoecologist at UC Berkeley, noted that while Mesozoic animals were suspected to consume angiosperm diaspores, botanical evidence was lacking. Co-author Cindy Looy, a paleobotanist at UC Berkeley, described the deposit as a snapshot of a mature tropical forest, with ground cover and leaves preserved in ash. The site was located 125 miles inland from the Western Interior Seaway during the Late Cretaceous. Selena Smith, a paleobotanist at the University of Michigan not involved in the study, commented that the findings align with Cretaceous-era diversification of plant size, leaves, and flowers.