China’s new Dinosaur fossil discovery- Knocking Archaeopteryx off its perch?
Archaeopteryx is considered by many to be the first bird, being of about 150 million years of age. Archaeopteryx was discovered in 1861, two years after Charles Darwin published ” On the Origin of Species”,ever-since it has become a textbook example for transitional fossil
In the 150th anniversary of its discovery, the position of Archaeopteryx as the earliest-known bird has been weakened thanks to the discovery of increasing numbers of feathered, bird-like dinosaurs over the past decade and a half. These claims are now further strengthened by a new fossil discovery from China which can knock iconic bird off its perch,in a reassessment of the bird-dinosaur family tree.
This new discovery, a feathered, chicken-sized dinosaur named Xiaotingia zhengi was unearthed from China’s Liaoning Province, a source of many proto-dino-bird fossils.Xiaotingia is also a dinosaur, but when authors did phylogenetic analysis of proto-dino-birds, Archaeopteryx was shifted from birds branch to dinosaurs side. According to findings from Xu’s team published in latest issue of Nature journal , place Archaeopteryx on new branch of dinosaurs called deinonychosaur to which Xiaotingia also belongs. This group eventually split from the rest of Dinosaurs leading to origin of birds.
If archaeopteryx was a dinosaur, this means flight evolved at least four times in vertebrates: in reptiles, birds, dinosaurs, and most recently in bats.
Lawrence Witmer from Ohio university states that with archaeopteryx dethroned from its iconic status of earliest bird, more recently discovered fossils, including epidexipteryx, jeholornis and sapeornis, become candidates for the world’s oldest bird. However, as the authors freely admit, finding some new proto-bird fossil could again change the avian family tree and restore Archaeopteryx’s premier status.
“There has been growing unease about the avian status of archaeopteryx as, one by one, its ‘avian’ attributes (feathers, wishbone, three-fingered hand) started showing up in non-avian dinosaurs. Perhaps the time has come to finally accept that archaeopteryx was just another small, feathered, bird-like theropod fluttering around in the Jurassic.”
– Lawrence Witmer at Ohio University
Reference :
An Archaeopteryx-like theropod from China and the origin of Avialae
Xing Xu, Hailu You,Kai Du & Fenglu Han
Nature 475,465–470 (28 July 2011) doi:10.1038/nature10288
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