Best-Preserved Feather Ever Found Inside Dinosaur Poop — SkimNews
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- David DeMar Jr at the University of Washington discovered the broken coprolite with a feather visible along its fractured surface in 2016 while collecting fish fossils in Montana's Hell Creek Formation, later teaming up with Jingmai O'Connor of the Field Museum to analyze it via micro-CT and 3D surface scanning.
- The 9.3-millimeter primary feather had a water-repellent structure similar to modern pelicans, with lightweight spongy cores surrounded by a harder outer layer — O'Connor called it "a feather you could pick up off the ground" and "the best feather we've ever seen in a Mesozoic deposit."
- Leg bone fragments measuring 18 and 12 millimeters matched hesperornithiformes — flightless, short-winged diving birds related to modern loons and grebes, and part of the broader neornithes lineage that gave rise to every bird alive today.
- Two fluffy body feathers found alongside showed loosely arranged primitive branches echoing feathers in 100-million-year-old Myanmar amber, suggesting the bird occupied a "middle ground" between ancient and modern plumage.
- O'Connor argued the primitive body feathers would have been poor insulators — good enough for the Mesozoic greenhouse but not for the post-asteroid "winter," potentially explaining why hesperornithiformes died out while one branch of birds survived.
- The coprolite also contained 3- to 4-millimeter diamond-shaped gar fish scales too small for the predator, suggesting the bird ate the gar and the dropping came from a Nanotyrannus or a young Tyrannosaurus rex — one coprolite thus capturing evidence of at least three species.
- Published in Current Biology, the finding pushes the emergence of modern-type feathers back by 10 million years and opens new questions about feather evolution, according to Frank Muzio at the University of Connecticut.
Why it matters: The coprolite gives paleontologists the first direct look at the plumage of hesperornithiformes — flightless diving birds that vanished in the asteroid-driven extinction — and O'Connor's team argues their modern wing feathers paired with primitive, poorly insulating body feathers may explain why only the neornithes lineage survived, reshaping how researchers evaluate which traits mattered for survival 66 million years ago.
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