Dinosaur Coprolite Yields First Hesperornithiform Feathers

Overview

• A golf‑ball‑sized coprolite found in Montana in 2016 was CT‑scanned and, in a paper published Sept. 10, 2026, was shown to contain multiple feathers, tiny gar fish scales and small bird leg bones.
• The bird bones and associated remains were identified as coming from a hesperornithiform, making these the first feathers assigned to that extinct, loon‑like diving bird group.
• The feathers show a mix of modern, waterproof flight features and primitive, fuzzy body plumage, and two feathers display a spongy shaft structure previously known only from younger fossils.
• The authors propose that poorer body insulation in non‑modern feather types could have made some Cretaceous birds more vulnerable to the post‑impact “impact winter,” a hypothesis the team calls provisional pending more specimens.
• The discovery demonstrates that micro‑CT scanning of museum coprolites can reveal unexpected soft tissues and direct predator‑prey links, and the authors urge systematic CT surveys to test their survival hypothesis and find more rare fossils.