100-million-year-old bird footprints discovered in Australia

Researchers say they have discovered Australia's oldest known bird footprints, a pair of tracks left in a sandy riverbank in Australia during the age of dinosaurs. 

Drawing by Anthony Martin
This illustration shows how the landing track was probably made as a bird set down on the moist sand of a riverbank after flying.
Anthony Martin
A drag mark made by the rear toe on one of the Cretaceous bird tracks indicates that it was a flight landing track.

Two thin-toed footprints pressed into a sandy riverbank more than 100 million years ago are Australia's oldest known bird tracks, researchers say.

The prints were found among the fossil-rich cliffs of Dinosaur Cove on the coast of southern Victoria. Researchers think the tracks were left by a prehistoric bird species likely the size of a great egret or a small heron during the Early Cretaceous Period.

At that time, the world was warmer and the continents were arranged in different positions than they are today. The site of Dinosaur Cove was located in a floodplain in a great rift valley that formed as the supercontinent Gondwana started breaking apart, tearing Australia away from Antarctica. [Avian Ancestors: Dinosaurs That Learned to Fly]

A long drag mark leading up to one of the fossilized footprints was a telltale sign that these tracks were left by flying creatures, explained study researcher Anthony Martin, a paleontologist at Emory University in Atlanta.

The bird tracks were found very close to another footprint that looks like it was left by a non-avian theropod, possibly one of the coelurosaurs, the group of dinosaurs most closely related to birds that includes beasts like the Tyrannosaurus rex.

All three ancient footprints were locked in sandstone in an area smaller than a square foot (650 square centimeters), which gives researchers insight into the types of creatures that lived together at Dinosaur Cove during the Early Cretaceous.

"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," Martin said.

The researchers think the footprints were left at a time when the riverbank was covered in moist sand, 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 their tracks at Dinosaur Cove also had one backwards-facing toe. That feature is found on some bird feet today, and T. rex even had a vestigial rear toe. Studying 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.

Follow Megan Gannon on Twitter and Google+. Follow us @livescienceFacebook Google+. Original article on LiveScience.

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to 100-million-year-old bird footprints discovered in Australia
Read this article in
QR Code to Subscription page
Start your subscription today