Archaeopteryx had pennaceous (quill-like) feathers all over its body, not only its wings, a new fossil – only the 11th of the creature found – reveals.
These “trousers” were probably used for display, say scientists from Germany, writing in Nature journal.
Their discovery adds weight to the theory that feathers originally evolved for purposes other than flight.
Archaeopteryx caused a major stir when the first fossil was unearthed in Germany in 1861 – just two years after Charles Darwin published On The Origin of Species.
With the claws and teeth of a dinosaur, but the feathers of a bird, it was clearly a transitional form – apparent proof of Darwin’s theory.
Its German name “Urvogel” means “first bird”.
And though earlier bird-like dinosaurs have been unearthed since, many scientists still believe Archaeopteryx was the first capable of “flight” as we know it today.
The 11th fossil specimen was announced in 2011 and is remarkably well preserved, with detailed impressions of feathers all over its skeleton. The feathers are long and symmetrical on its upper leg and shorter lower down.