KU News Release
June 16, 2011
Contact: Brendan M. Lynch, University Relations, 785-864-8855
Researchers positively identify bedeviling shapes in High Plains rock outcrops
LAWRENCE — For more than a century, weird spirals and latticeworks of pancake-shaped rocks jutting from outcrops and road cuts around the High Plains have perplexed scientists and locals.
As far back as the 1890s, the shapes led bewildered paleontologists to dub them “devil’s corkscrews” and “devil’s cakes.” Since then, other investigators have theorized that the lattices — commonly found in a unit of rock called the Ogallala Formation — were remnants of prehistoric plants or even fossilized dung piles.
Now, a collaborative research team from the University of Kansas and Fort Hays State University has solved the scientific mystery. Through careful study of examples found along a ridge called “Devil’s Backbone” in Scott County, they’ve concluded the odd shapes are fossil nests that were built by ants 10 million to 15 million years ago.
“A lot of them are pretty well exposed though erosion,” said Brian Platt, a KU doctoral student in geology and research support specialist at the Kansas Geological Survey, who was part of the team. “We’d brush them off and dig at them a little deeper. But it’s impossible to extract an entire nest because they are so delicate. The vertical tubes are only up to a centimeter in diameter. But we were able to break off some of the pieces, collect them and compare them with modern insect nests.”
Relying on plaster and metal casts of underground networks of present-day ants made by Walter Tschinkel of Florida State University, the KU researchers were able to verify that ancient ants created the High Plains structures. (One recent study of similar structures in Nebraska had suggested that ants might be responsible, but their exact origin remained elusive.)
“The modern nests have pancake-shaped chambers and vertical tubes that connect them,” Platt said. “When you look at the fossil structures in Scott County — with the individual pancake pieces and overall structure — they look exactly like the modern ant nests. We were pretty excited when we saw them and realized we were the first to recognize that these are fossil ant nests and not algal structures or dung patties or anything like that.”
Their findings soon will be published in the science journal Palaeogeography, Palaeoclimatology, Palaeoecology.
The enigmatic fossils were first examined in the field by research team member Joseph Thomasson, curator at the Sternberg Museum of Natural History at Fort Hays State University. Suspecting that the fossils may be prehistoric ant nests, Thomasson showed them to paleontologist Jon Smith, assistant scientist at the Kansas Geological Survey, which is based at KU. Smith built a team including Platt, Thomasson and Greg Ludvigson, associate scientist with the survey, to further analyze the evidence. After detailed investigations, the team confirmed that the fossils were ancient nests.
“It’s been an ongoing process, and whenever we’d get a chance, we’d go out and take a look at them,” said Platt. “We were out there starting in 2008. We really wanted to do a good job describing them, so we were careful about taking individual measurements of all the nest parts. It’s been a great collaborative project.”
The fossil ant nests provide important information on hidden biodiversity, soil moisture and ancient climate conditions, according to the researchers.
“Ants are by far the most common insects in modern ecosystems,” Platt said. “Their nests can dramatically alter the soil structure by building extensive galleries, tunnels and networks that aerate the soil and help with water infiltration. Combined studies on modern and fossil ant nests will shed more light on those influences that ants have on the soil.”
Perhaps just as important, the researchers were able to put to rest any questions about the strangely shaped rocks.
“The fossils were right there at the side of the road,” said Platt. “We did have a number of locals stop and ask us what we were doing. And we were happy to talk to people about what were studying out there. They were as curious as we were. They had seen these things their whole lives.”
The University of Kansas is a major comprehensive research and teaching university. University Relations is the central public relations office for KU's Lawrence firstname.lastname@example.org | (785) 864-3256 | 1314 Jayhawk Blvd., Lawrence, KS 66045