The meteorite crash that coincided with the vanishing of the dinosaurs 65 million years ago also saw a fast refuse in prehistoric bird species.
Only a little bird groups survived through the accumulation death, from which all contemporary birds are descended.
There has been a long standing argue over the destiny of the earliest "archaic" birds, which first evolved about 200 million years ago.
Whether their populations declined gradually towards the end of the Cretaceous time, or whether they suffered unexpected accumulation extinction at the Cretaceous-Tertiary (K-T) boundary is unsettled, owing to contradictory evidence.
DNA studies have attempted to date the source of contemporary birds; some propose that they appeared before the extermination of dinosaurs, with big facts of them existing through the extermination affair.
Bird bones are very hard to protect as fossils as they are little and glow, and easily injured or swept away in rivers.
But the new investigate, headed by Dr Longrich, have made use of fragmentary bird fossils composed up to 100 years ago, from locations across North America.
Only a little bird groups survived through the accumulation death, from which all contemporary birds are descended.
There has been a long standing argue over the destiny of the earliest "archaic" birds, which first evolved about 200 million years ago.
Whether their populations declined gradually towards the end of the Cretaceous time, or whether they suffered unexpected accumulation extinction at the Cretaceous-Tertiary (K-T) boundary is unsettled, owing to contradictory evidence.
DNA studies have attempted to date the source of contemporary birds; some propose that they appeared before the extermination of dinosaurs, with big facts of them existing through the extermination affair.
Bird bones are very hard to protect as fossils as they are little and glow, and easily injured or swept away in rivers.
But the new investigate, headed by Dr Longrich, have made use of fragmentary bird fossils composed up to 100 years ago, from locations across North America.
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