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Late Triassic bird tracks date from Eocene



From: Ben Creisler
bcreisler@gmail.com


A new item in Nature:

Ricardo N. Melchor, Robert Buchwaldt & Samuel Bowring (2013)
A Late Eocene date for Late Triassic bird tracks.
Nature 495, E1–E2 (21 March 2013)
doi:10.1038/nature11931
http://www.nature.com/nature/journal/v495/n7441/full/nature11931.html


ARISING FROM R. N. Melchor, S. De Valais & J. F. Genise Nature 417,
936–938 (2002)

Bird-like tracks from northwest Argentina have been reported as being
of Late Triassic age. They were attributed to an unknown group of
theropods showing some avian characters. However, we believe that
these tracks are of Late Eocene age on the basis of a new weighted
mean 206Pb/238U date (isotope dilution–thermal ionization mass
spectrometry method) on zircons from a tuff bed in the sedimentary
succession containing the fossil tracks. In consequence, the mentioned
tracks are assigned to birds and its occurrence matches the known
fossil record of Aves.