By Mark Brown, Wired UK

Palaeontologists in America have discovered the youngest known dinosaur bones, after digging up the fossilized remains of a Triceratops or Torosaurus’ 45cm-long brow horn.

But what makes this find — from the Hell Creek Formation in the wastelands of south-east Montana — even more special is its ramifications for the current theories on what wiped out the prehistoric lizards.

It’s generally believed that a colossal asteroid pummeled into Mexico’s Yucatan Peninsula about 65 million years ago, which led to a mass extinction of any animal that couldn’t fly, swim or burrow into the ground.

But some skeptics believe that the dinosaurs were already on a sharp decline, or even extinct, when the asteroid hit. This would have been thanks to climate change, unpredictable sea levels and intense volcanic activity.

This dissenting theory has come to prominence because no fossils have even been found within three meters of the Cretaceous-Tertiary (K-T) boundary — an area in the sedimentary rock that’s packed with rare elements like Iridium and Quartz, which signifies when the asteroid impacted the planet.

This newly discovered brow horn was found just 13cm below that all-important line. It proves that this Ceratopsian dinosaur (probably a Triceratops or Torosaurus) was wandering about right up to the impact event, and the authors believe this debunks the dissenting theory.

In the paper, published in Biology Letters, the team writes: “The in situ specimen demonstrates that a gap devoid of non-avian dinosaur fossils does not exist and is inconsistent with the hypothesis that non-avian dinosaurs were extinct prior to the K-T boundary impact event.”

Image: Daderot/Wikipedia

Source: Wired.co.uk

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