Feather in dinosaur dung hints why only some birds survived extinction

A 66-million-year-old feather found inside a dinosaur coprolite in Montana is the best-preserved from the Mesozoic, per researchers. It belonged to an extinct aquatic bird, and its mix of modern and primitive plumage may explain why only ancestors of today's birds survived the asteroid winter.

Bottom line — The feather, described in Current Biology, is the first from a hesperornithiform and the first found in a coprolite.

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• The coprolite was discovered in 2016 by David DeMar Jr. of the Burke Museum while he was crawling for fish fossils in the Hell Creek Formation, per the study.
• Micro-CT scanning revealed multiple feathers, gar fish scales, and leg bones from a hesperornithiform — an extinct loon-like diving bird, according to the team.
• Lead author Jingmai O'Connor of the Field Museum said the bird likely had modern waterproof feathers on its limbs but primitive, downy body feathers, per El País.
• The researchers hypothesise that only crown birds had the full suite of insulating body feathers needed to survive the post-asteroid impact winter, per RNZ.
• Not all experts are convinced: Julia Clarke of UT Austin told NPR the fragments are too incomplete to explain survivorship, calling the food-chain snapshot a 'Cretaceous turducken.'
• O'Connor called the find 'a call to action' for museums to CT-scan their coprolite collections, per the ABC.
• The feather's shaft has a square cross-section with a sponge-like centre — a feature previously unknown in Mesozoic feathers, per Sci.News.

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