/ 31 January 2020

Jurassic parkour in SA lava fields

Here comes the hotstepper: Traces of a dinosaur, similar to the carnivorous Coelophysis above, were among the ichnofossils discovered near Clarens in the Free State by researchers from the University of Cape Town. (Luisa Ricciarini/Leemage)

Thanks to a chance discovery and a great deal of detective work, a team of geologists from the University of Cape Town has uncovered trace fossils of dinosaurs and other Jurassic period creatures on a farm just outside of
Clarens in the Free State.

Led by associate professor Emese Bordy of the University of Cape Town, and documented in the PLOS One scientific journal this week, the team’s discovery broadens our understanding of life 183-million years ago — not just of the dinosaurs of the Early Jurassic period, but also of the environment they lived in.

Life in South Africa was considerably different 183-million years ago. For starters, South Africa wasn’t really here. There wasn’t an Africa to be the south of. Instead, the lands that would become Africa, South America, Australia, India and Antarctica were still joined together in a supercontinent called Gondwana. And the patch of land where we lay our scene was a sandy desert, much like the Sahara is now.

At least, that’s what it was like when it wasn’t covered by gigantic fields of molten rocks that poured out onto the surface as lava flowed in a series of volcanic eruptions that turned the Karoo Basin into a land of fire.

But the environment was not always toxic, traumatic and uninhabitable during this time, says Bordy. Just … occasionally. Between each violent eruption there were moments of calm. These interludes were all too brief, in geological terms, but they could last for hundreds of thousands of years. Enough time for rain to fall, plants to brush the sands, and even for dinosaurs and early mammals to eat, prey and live.

It was over such terrain that three groups of now-extinct animals scampered, trotted and plodded, their feats of prehistoric parkour leaving tracks that are now giving us new insight into the life that endured in the early Jurassic.

The smallest was most likely a synapsid — part of an animal group more closely related to mammals than reptiles, probably resembling much more a lively opossum than a lizard.

Next, a two-legged, carnivorous dinosaur — like Coelophysis, whose bones have been uncovered in South Africa, Zimbabwe and Lesotho — but also in far-off Arizona in the United States, reminding us that objects in our rear-view paleontological mirror used to be closer than they now appear.

And, finally, the ornithischian — a plant-eater that lumbered along on all fours, not too distantly related to the stegosaurus. Notably, after previous tentative sightings in Zimbabwe, it is debuting at last as a named ichnofossil which Bordy and her colleagues have dubbed Afrodelatorrichnus ellenbergeri. This is in honour of Paul Ellenberger, a French priest whose work from the 1950s to the 1970s earned him a reputation as the father of vertebrate ichnology in southern Africa.

Ichnology — the study of trace fossils — is very much Bordy’s field. These are not the petrified skeletal remains you might be thinking of. Rather they are the traces, or ichnites, that they left behind. Their footprints, especially, but also their burrows, and even droppings. Instead of just showing us what they looked like, they show us how they behaved, and how they might have lived.

Like so many scientific discoveries, both serendipity and hard work played important roles in this story, which began when Bordy was poring over old documents and chanced upon a curious reference, which prompted her to contact Free State University to ask them to trace an unpublished master’s dissertation from 1964 in their library archives.

After some back and forth, Bordy finally got her hands on the document “and once I could read it, I found this black and white photograph of a dinosaur track and became very excited.”

A best-selling novel’s worth of detective work followed, as the next challenge was pinpointing the location of the track and gaining permission to visit the land on which it lay. Thanks to assiduous tagging of his shots from the area, the name of the farm in the Free State — Highlands — was gleaned from the work of a nature photographer. And with the help of Erika van Edeen, an enthusiastic local historian and budding science enthusiast, Bordy was able to find the name of the owner and get the go-ahead to track on his property.

It was not a successful hunt. At least, not at first. Bordy and her team spent hours on the farm, searching for tracks in the blazing heat — in vain. Glum and dispirited, they reluctantly called it a day, and were on their way back to their truck when something caught Bordy’s eye.

Excitement grew with each step as they unearthed the site, discovering 25 trackways, in all, sandwiched between layers of basalt and sandstone. “We found a lot more than we expected based on that single black and white photograph” says Bordy. Even Van Edeen, who had accompanied the trackers, got caught up in the excitement. “This is science in action!” she exclaimed. “And I am part of it!”

After returning from the field, Bordy turned her attention to analysing the find with her students and co-authors Akhil Rampersadh, Miengah Abrahams, Howard Head and tracker expert Professor Martin Lockley. Before publishing they would bring together the work of field trackers, sedimentologists, stratigraphers, paleobotanists, vertebrate paleontologists and volcanologists, among others. Not to mention the algorithms and equations that conjured computer models of the animals’ tracks, and the way they walked.

The synapsid, the theropod and the ornithischian tracks they uncovered give us a new window on the incredibly harsh and stressful conditions in which life endured. For if one thing is common to all who have lived here, it’s tenacity.

As Bordy quotes the trail-blazing fossil hunter Ellenberger in her PLOS One paper: “La vie ne peut qu’avoir continué!”

Life can only go on — and, with it, the science.