100 million year old bird tracks discovered in Australia
NewsTuesday 29 October 2013
Researchers have said that two thin-toed footprints which were found pressed into a sandy riverbank more than 100 million years ago are Australia’s oldest known bird tracks.
The prints in question were discovered in the fossil-rich cliffs of Dinosaur Cove on the coast of southern Victoria. When speculating about the prints, the researchers have said that the tracks could have been left by a prehistoric bird species that was likely the size of a great egret or a small heron during the Early Cretaceous Period.
A telltale sign that these tracks were left by flying creatures, was the long drag mark leading up to one of the footprints, according to the study researcher Anthony Martin, a paleontologist at Emory University in Atlanta.
The drag mark at the rear toe on one of the Cretaceous bird tracks indicates that it was a flight landing track.
The bird tracks were discovered very close to another footprint that looks as if it was left by a non-avian theropod. This other print could have belonged to one of the coelurosaurs, which is the group of dinosaurs that was most closely related to birds that included beasts like the tyrannosaurus rex.
According to the Huffington Post, Martin said: "These tracks are evidence that we had sizeable, flying birds living alongside other kinds of dinosaurs on these polar, river floodplains, about 105 million years ago.”
The researchers have also stated that they think the footprints were left at a time when the riverbank was covered in moist sand, which was possibly after spring and summer floodwaters had subsided.
Martin said it remains unclear whether these ancient birds lived in the region during the polar winter or migrated there during the spring and summer.
The birds that left the tracks in question, also had one backwards-facing toe, which features on some bird feet today. The T-rex also had a vestigial rear toe, and the studying of the changing toe-arrangement of birds and their dinosaur cousins could give researchers insight into the evolution of these species.
"In some dinosaur lineages, that rear toe got longer instead of shorter and made a great adaptation for perching up in trees," Martin explained in a statement. "Tracks and other trace fossils offer clues to how non-avian dinosaurs and birds evolved and started occupying different ecological niches."
The finding was described this month in the journal Palaeontology.