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Oldest USA Cretaceous bird tracks found in Utah
A new online paper:
Martin G. Lockley, Lisa G. Buckley, John R. Foster, James I. Kirkland
& Donald D. Deblieux (2014)
First report of bird tracks (Aquatilavipes) from the Cedar Mountain
Formation (Lower Cretaceous), eastern Utah.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
First report of bird tracks from the Lower Cretaceous Cedar Mountain
First bivariate and multivariate analysis of multiple Cretaceous avian
Statistical support for validity of most well-known Cretaceous avian ichnotaxa.
Oldest evidence of birds from Cretaceous of USA.
More than 130 footprints representing ~ 43 trackways of birds (avian
theropods) and two non-avian theropods occur as seven separate
assemblages on loose blocks recovered from the Poison Strip Member of
the Cedar Mountain Formation, near the Stikes Quarry locality in
eastern Utah. Six of assemblages, four with bird tracks and two with
small non avian theropod tracks, are inferred to originate from the
same stratigraphic horizon, and can therefore be considered part of
the same ichnofauna. The seventh assemblages comes from a different
horizon a few meters above that yielding the other six assemblages.
The bird tracks are all attributed to the ichnogenus Aquatilavipes, a
track type morphologically similar to those of modern shorebirds. The
ichnogenus is also known from broadly coeval ichnofaunas from South
Dakota and Canada, and the identification is confirmed by detailed
comparative analysis of available Aquatilavipes samples using
bivariate and multivariate analyses. This is the first definitive
report of bird tracks from the Cedar Mountain Formation and the first
evidence of birds from this otherwise richly fossiliferous unit. The
ichnofauna is therefore quite unique in comparison with others from
this same formation.