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Re: Bird analysis update 3: reweighting

David Marjanovic (david.marjanovic@gmx.at) wrote:

<Those gaps of tens of Ma are currently inevitable, no matter what the
phylogenetic trees look like. There is Solnhofen (end of Late Jurassic),
then there is nothing, then there is *Noguerornis* (early Early
Cretaceous), then there's another gap, and only then comes Liaoning
(middle and late Early Cretaceous). No bird fossils are yet known from
those gaps.>

  Wang et al. dated the Sihetun "member" to the middle Barremian, and
Swisher et al. suggested an even older age for the volcanoclastics of
Lujiatun ("lowermost member") of around 139mya, indicating that the Yixian
is virtually as old as the Cretaceous Jurassic transition, with a
separation of only a few million years from the Upper Malm Solnhofen
Formation, so this incredibly reduces the gap of "bird-like" dinosaurs and
*Archaeopteryx*. Hope this helps.


Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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