Seven years ago, museum curator Christian Sidor showed Jack Conrad a fossil he dug up in the Bridger Formation of the Rocky Mountains in Wyoming. "Hey, what’s this?" Sidor asked.
Conrad stared at the find with fascination. Could it be? It looked like the ancient remains of a reptile that remarkably walks on water. The fossil looked incredibly time-worn, far older than any he had ever seen, but he was sure. "It's the Jesus lizard," Conrad said, muttering in awe.
It wasn't just a Jesus lizard. It might be the Jesus lizard. Research authored by Conrad, a research associate at the American Museum of Natural History, placed the fossil at 48 million years old, at least 5 million years older than a previously discovered skeleton. The study was published Wednesday in the Journal PLOS One.
Lizards that run so fast on buoyant webbed feet that they skitter across water are around today, but not in Wyoming. The nine known species, including iguanas and chameleons, only range between Mexico and Colombia, although an invasive group is living in Florida. This means, Conrad said, that millions of years ago, Wyoming's climate was probably similar to the tropics closer to the equator. And if that's the case, scientists now have more reason to believe that various types of tropical and subtropical flora and fauna thrived in what is now the Cowboy State.
"If you were to look at the U.S. 48 million years ago, you’re looking at a tropical planet. A rain forest, lots of lakes and rivers, gators and monitor lizards, small boa constrictor-like snakes," said Conrad, an assistant professor of anatomy at the New York Institute of Technology, which helped fund the study.
"This was a super cool time. The first big hoofed mammals, like rhinos on steroids, emerged. The first big mammal carnivores were there, 17 million years after dinosaurs. There were big alligators and crocks, birds exploding into various varieties," Conrad said. On the other hand, he said, "this would have been a very violent time to be a lizard. Everything ate them. Lizards are typically very low on the food chain."
But it wasn't like the Jesus lizard just waited around to be sacrificed. If it was anything like today's variety, and Conrad believes it was -- in fact he believes it is among the purest forms of these types of lizards -- it ate flowers and bugs and the occasional snake. In order to eat this kind of lizard, prey animals have to catch it. Jesus lizards would put Jamaican sprinter Usain Bolt, the fastest man on Earth, to shame. To run proportionately fast, a human would have to gallop at 65 miles per hour.
"This is the modern Jesus lizard living 48 million years ago," the researcher said. "It’s very, very similar. It tells us this group has been around a lot longer than we thought, and it diversified a lot more than we thought.
"They are so fast. You can’t approach them. You hear them in the water when they start splashing across. They run on their hind legs," Conrad said.
Conrad took a time out for honesty: "I still can’t say this animal was able to run across water or not. If your sister’s good at basketball and your cousin’s good at basketball, it doesn’t mean you are."
But all signs in a fossil so similar to the current lizard's bone structure point to this unique ability. He speculates that the ancient lizard, Babibasilscus alxi, was "likely active during the day and spent a lot of time in trees. Each small tooth had three points suitable for eating snakes, lizards, fish, insects and plants, but with a fairly large cheekbone, the lizard may have enjoyed larger prey items as well," according to a statement about the study.
The fossil itself is a fearsome looking thing. It has big holes where the eyes would have been and a bony slab sticking out of its skull. Frankly it's reminiscent of the upright, walking, make-believe Sleestak lizard from the movie, "Land of the Lost." It seems apropos that it was discovered by Sidor in the Wyoming badlands, a rocky and hilly area in the southwest part of the state.
Sidor took his find to the Burke Museum in Seattle, where he works as a curator and associate director of research and collections. It sat for years awaiting study until Conrad came along.
"Sometimes these studies take longer than they should," Conrad admitted. "It’s just a matter of the time and specific interest. We have more fossils than we can conceivably study."