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Oldest avian footprints from Australia



From: Ben Creisler
bcreisler@gmail.com


A new online paper:

Anthony J. Martin, Patricia Vickers-Rich, Thomas H. Rich & Michael Hall (2013)
Oldest known avian footprints from Australia: Eumeralla Formation
(Albian), Dinosaur Cove, Victoria.
Palaeontology (advance online publication)
DOI: 10.1111/pala.12082
http://onlinelibrary.wiley.com/doi/10.1111/pala.12082/abstract

Two thin-toed tridactyl tracks in a fluvial sandstone bed of the
Eumeralla Formation (Albian) at Dinosaur Cove (Victoria, Australia)
were likely made by avian trackmakers, making these the oldest known
fossil bird tracks in Australia and the only Early Cretaceous ones
from Gondwana. These tracks, which co-occur on the same surface with a
slightly larger nonavian theropod track, are distinguishable by their
anisodactyl form, hallux impressions and wide digit II–IV divarication
angles. A lengthy hallux impression and other deformational structures
associated with one track indicate foot movement consistent with an
abrupt stop, suggesting its tracemaker landed after either flight or a
hop. The single nonavian theropod track is similar to other tracks
described from the Eumeralla Formation at another locality. The avian
footprints are larger than most Early Cretaceous avian tracks recorded
worldwide, indicating sizeable enantiornithine or ornithurine species
in formerly polar environments of Australia. The avian tracks further
supplement scant body fossil evidence of Early Cretaceous birds in
southern Australia, which includes a furcula from the Wonthaggi
Formation. Because of this discovery, Dinosaur Cove, previously known
for its vertebrate body fossils, is added to a growing list of Early
Cretaceous vertebrate tracksites in southern Australia.