Different tracks, same dinosaurs: Brown researchers dig deeper into dinosaur movements

Related Articles

Related Articles

When picturing dinosaur tracks, most people imagine a perfectly preserved mold of a foot on firm layer of earth.

But what if that dinosaur was running through mud, sinking several inches — or even up to their ankles — into the ground as it moved?

Using sophisticated X-ray-based technology, a team of Brown University researchers tracked the movements of guineafowl to investigate how their feet move below ground through various substrates and what those findings could mean for understanding fossil records left behind by dinosaurs.

 

They found that regardless of the variability in substrates, or the guineafowl moving at different speeds, sinking at different depths or engaging in different behaviors, the birds’ overall foot movement remained the same: The toes spread as they stepped onto the substrate surface, remained spread as the foot sank, collapsed and drew back as they were lifted from the substrate, and exited the substrate in front of the point of entry, creating a looping pattern as they walked.

And part of what that means is that fossilized dinosaur tracks that look distinct from each other, and appear to be from different species, might instead come from the same dinosaurs.

“This is the first study that’s really shown how the bird foot is moving below ground, showing the patterns of this subsurface foot motion and allowing us to break down the patterns that we’re seeing in a living animal that has feet similar to those of a dinosaur,” said Morgan Turner, a Ph.D. candidate at Brown in ecology and evolutionary biology and lead author of the research. “Below ground, or even above ground, they’re responding to these soft substrates in a very similar way, which has potentially important implications for our ability to study the movement of these animals that we can’t observe directly anymore.”

The findings were published on Wednesday, July 1, in the Royal Society journal Biology Letters.

To make the observations, Turner and her colleagues, Professor of Biology and Medical Science Stephen Gatesy and Peter Falkingham, now at Liverpool John Moores University, used a 3D-imaging technology developed at Brown called X-ray Reconstruction of Moving Morphology (XROMM). The technology combines CT scans of a skeleton with high-speed X-ray video, aided by tiny implanted metal markers, to create visualizations of how bones and muscles move inside humans and animals. In the study, the team used XROMM to watch guineafowl move through substrates of different hydration and compactness, analyzing how their feet moved underground and the tracks left behind.

Sand, typically a dense combination of quartz and silica, does not lend itself well to X-ray imaging, so the team used poppy seeds to emulate sand. Muds were made using small glass bubbles, adding various amount of clay and water across 107 trials to achieve different consistencies and realistic tracks.

They added metal markers underneath the claws of the guineafowl to allow for tracking in 3D space. It’s these claw tips that the researchers think are least disturbed by mud flow and other variables that can impact and distort the form of the track.

Despite the variation, the researchers observed a consistent looping pattern.

“The loops by themselves I don’t think are that interesting,” Gatesy said. “People are like, ‘That’s nice. Birds do this underground. So what?’ It was only when [Turner] went back into it and said, ‘What if we slice those motion trails at different depths as if they were footprints?’ Then we made the nice connection to the fossils.”

By “slicing” through the 3D images of the movement patterns at different depths, the researchers found similarities between the guineafowl tracks and fossilized dinosaur tracks.

“We don’t know what these dinosaurs were doing, we don’t know what they were walking through exactly, we don’t know how big they were or how deep they were sinking, but we can make this really strong connection between how they were moving and some level of context for where this track is being sampled from within that movement,” Turner said.

By recognizing the movement patterns, as well as the entry and exit point of the foot through various substrates, the team says they’re able to gain a better understanding of what a dinosaur track could look like.

“You end up generating this big diversity of track shapes from a very simple foot shape because you’re sampling at different depths and it’s moving in complicated ways,” Gatesy said. “Do we really have 40 different kinds of creatures, each with a differently shaped foot, or are we looking at some more complicated interaction that leaves behind these remnants that are partly anatomical and partly motion and partly depth?”

To further their research, the team spent time at the Beneski Museum of Natural History at Amherst College in Massachusetts, which is home to an expansive collection of penetrative tracks discovered in the 1800s by geologist Edward Hitchcock.

Hitchcock originally believed that his collection housed fossil tracks from over 100 distinct animals. Because of the team’s work with XROMM, Gatesy now thinks it’s possible that at least half of those tracks are actually from the same dinosaurs, just moving their feet in slightly different ways or sampled at slightly different depths.

“Going to museum together and being able to pick out these features and say, ‘We think this track is low in the loop and we think this one is high,’ that was the biggest moment of insight for me,” Turner said.

Turner says she hopes their research can lead to a greater interest in penetrative tracks, even if they seem a little less pretty or polished than the tracks people are used to seeing in museums.

“They have so much information in them,” Turner said, “and I hope that this gives people a lens, a new way to view these footprints and appreciate the movement preserved within in them.”

BROWN UNIVERSITY

Header Image – Using sophisticated X-ray-based technology, a team of Brown University researchers tracked the movements of guineafowl to investigate how their feet move below ground through various substrates and what those findings could mean for understanding fossil records left behind by dinosaurs. Image Credit : Brown University

Download the HeritageDaily mobile application on iOS and Android

More on this topic

LATEST NEWS

Walking, Talking and Showing Off – a History of Roman Gardens

In ancient Rome, you could tell a lot about a person from the look of their garden. Ancient gardens were spaces used for many activities, such as dining, intellectual practice, and religious rituals.

Curious Kids: How did the First Person Evolve?

We know humans haven’t always been around. After all, we wouldn’t have survived alongside meat-eating dinosaurs like Tyrannosaurus rex.

Ring-like Structure on Ganymede May Have Been Caused by a Violent Impact

Researchers from Kobe University and the National Institute of Technology, Oshima College have conducted a detailed reanalysis of image data from Voyager 1, 2 and Galileo spacecraft in order to investigate the orientation and distribution of the ancient tectonic troughs found on Jupiter’s moon Ganymede.

Tracing Evolution From Embryo to Baby Star

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) took a census of stellar eggs in the constellation Taurus and revealed their evolution state.

“Woodhenge” Discovered in the Iberian Peninsula

Archaeologists conducting research in the Perdigões complex in the Évora district of the Iberian Peninsula has uncovered a “Woodhenge” monument.

New Fossil Discovery Shows How Ancient ‘Hell Ants’ Hunted With Headgear

Researchers from New Jersey Institute of Technology (NJIT), Chinese Academy of Sciences and University of Rennes in France have unveiled a stunning 99-million-year-old fossil pristinely preserving an enigmatic insect predator from the Cretaceous Period -- a 'hell ant' (haidomyrmecine) -- as it embraced its unsuspecting final victim, an extinct relative of the cockroach known as Caputoraptor elegans.

New Algorithm Suggests That Early Humans and Related Species Interbred Early and Often

A new analysis of ancient genomes suggests that different branches of the human family tree interbred multiple times, and that some humans carry DNA from an archaic, unknown ancestor.

Long Neck Helped Reptile Hunt Underwater

Its neck was three times as long as its torso, but had only 13 extremely elongated vertebrae: Tanystropheus, a bizarre giraffe-necked reptile which lived 242 million years ago, is a paleontological absurdity.

Popular stories

Port Royal – The Sodom of the New World

Port Royal, originally named Cagway was an English harbour town and base of operations for buccaneers and privateers (pirates) until the great earthquake of 1692.

Matthew Hopkins – The Real Witch-Hunter

Matthew Hopkins was an infamous witch-hunter during the 17th century, who published “The Discovery of Witches” in 1647, and whose witch-hunting methods were applied during the notorious Salem Witch Trials in colonial Massachusetts.

Did Corn Fuel Cahokia’s Rise?

A new study suggests that corn was the staple subsistence crop that allowed the pre-Columbian city of Cahokia to rise to prominence and flourish for nearly 300 years.

The Real Dracula?

“Dracula”, published in 1897 by the Irish Author Bram Stoker, introduced audiences to the infamous Count and his dark world of sired vampiric minions.