Revising the fossil record
Posted on March 16, 2012
The ongoing construction work for the historic expansion of the Panama Canal is changing evolutionary biologists' understanding of the evolution of species in the New World.
Workers recently uncovered the fossils of camels, Aguascalientia panamaensis and Aguascalientia minuta, animals with a long snout that roamed the tropical rainforests of the isthmus some 20 million years ago.
Associated Press writer Christine Armario turned to Professor of Biology John Kricher as one of several experts to offer perspective on the find. Her story was published by news media across the country, including ABC News, The Huffington Post and regional news outlets from Atlanta to Seattle.
"It's pretty unusual to find camel remains that age at that place," said John Kricher, a biology professor at Wheaton College in Massachusetts who specializes in tropical ecology and is not affiliated with the project. "It certainly is a significant find by any measure. And it rewrites something of mammalian deep time history."
After the story was published, Professor Kricher elaborated on his comments. "The fossil record is like a chronological book with many pages ripped out. You try to fill in the missing parts of the 'story' (in this case history)," he said. "Every now and then you find a missing page or two and that discovery may rewrite a bit of the story. That's what happened here."
"In the New World, modern camels are Andean, high-elevation animals, such as the llama and alpaca, or creatures of windswept grasslands, such as the vicuna and guanaco," said Kricher, an ornithologist and ecologist who has written extensively on the environment of the tropics and the Galapagos Islands that inspired Charles Darwin's work on evolution.
"The current large mammal fauna of South America is depauperate compared to what it was as recently as 3 million years ago. Many species of large mammals have gone extinct. With regard to camels, we know that animals such as the llama are camels and must therefore be related to the little Panamanian fossils. And North America, before people arrived, harbored numerous camel species, now all extinct."