All posts tagged: asteroid extinction

A feather found in dinosaur poop could help explain why birds survived the dinosaur extinction

A feather found in dinosaur poop could help explain why birds survived the dinosaur extinction

A fossilized dinosaur dropping from Montana’s Hell Creek Formation contains an exceptionally preserved bird feather, along with additional feathers, bones and fish scales from a bird eaten roughly 66 million years ago. The feathers probably belonged to a hesperornithiform, an extinct group of diving birds closely related to the lineage that produced modern birds, and reveal an unexpected mixture of modern waterproof feathers and more primitive body feathers. Researchers propose that differences in insulating plumage, and possibly molting strategies, may help explain why crown birds survived the catastrophic conditions following the end-Cretaceous asteroid impact while every other dinosaur lineage disappeared. A meal eaten by a dinosaur about 66 million years ago may have preserved a clue to one of paleontology’s biggest mysteries. Inside a small piece of fossilized dung from Montana, scientists discovered an extraordinarily well-preserved bird feather, additional feathers, tiny bones and fish scales. The specimen provides a rare look at the plumage of birds living immediately before the asteroid impact that wiped out nearly all dinosaurs. The research, published in Current Biology, was …

Tunas became large, warm-blooded predators long after the dinosaur extinction

Tunas became large, warm-blooded predators long after the dinosaur extinction

Tunas did not become large, fast and warm-blooded simply because an asteroid cleared the oceans of competing predators. Their defining traits appeared separately over tens of millions of years, complicating a familiar story about life after mass extinction. The asteroid impact 66 million years ago erased non-avian dinosaurs and many large marine predators. One long-held explanation proposed that tunas and other powerful fishes quickly expanded into the empty ecological roles. A new analysis from Yale University challenges that idea. By combining genetic evidence with fossils, researchers built the most complete time-calibrated evolutionary tree yet for Scombridae, the family that includes tunas, mackerels, bonitos and related fishes. The tree places the family’s origin near the Cretaceous-Paleogene extinction. Yet the traits that make modern tunas exceptional did not appear together or immediately afterward. Three independent origins of endothermy in Scombridae. Time-calibrated phylogeny of Scombridae estimated using a Bayesian node-dating approach, with branches coloured according to an ancestral state reconstruction of endothermy. (CREDIT: Proceedings of the Royal Society B) “Our results demonstrate the K-Pg extinction did not trigger …