Washington: The discovery of two new extinct camel species by scientists sheds new light on the history of the tropics, a region containing more than half the world's biodiversity and some of its most important ecosystems.
The study is the first published description of a fossil mammal discovered as part of an international project in Panama.
Funded with a grant from the National Science Foundation, University of Florida paleontologists and geologists are working with the Panama Canal Authority and scientists at the Smithsonian Tropical Research Institute to make the most of a five-year window of excavations during Panama Canal expansions that began in 2009.
The discovery by Florida Museum of Natural History researchers extends the distribution of mammals to their southernmost point in the ancient tropics of Central America.
The tropics contain some of the world’s most important ecosystems, including rain forests that regulate climate systems and serve as a vital source of food and medicine, yet little is known of their history because lush vegetation prevents paleontological excavations.
“We’re discovering this fabulous new diversity of animals that lived in Central America that we didn’t even know about before,” Bruce MacFadden, co-author of the study, said.
“The family originated about 30 million years ago and they''re found widespread throughout North America, but prior to this discovery, they were unknown south of Mexico,” he said.
Researchers described two species of ancient camels that are also the oldest mammals found in Panama – Aguascalietia panamaensis and Aguascalientia minuta.
Distinguished from each other mainly by their size, the camels belong to an evolutionary branch of the camel family separate from the one that gave rise to modern camels based on different proportions of teeth and elongated jaws.
“Some descriptions say these are ‘crocodile-like’ camels because they have more elongated snouts than you would expect,” Aldo Rincon, the lead author, said.
“They were probably browsers in the forests of the ancient tropics. We can say that because the crowns are really short,” he said.
Rincon discovered the fossils in the Las Cascadas formation, unearthing pieces of a jaw belonging to the same animal over a span of two years, he said.
“When I came back to the museum, I started putting everything together and realized, ‘Oh wow, I have a nearly complete jaw’,” Rincon said.
The study shows that despite Central America’s close proximity to South America, there was no connection between continents because mammals in the area 20 million years ago all had North American origins.
According to MacFadden, the Isthmus of Panama formed about 15 million years later and the fauna crossed to South America 2.5 to 3 million years ago.
The study has been published in the Journal of Vertebrate Paleontology.
First Published: Thursday, March 01, 2012, 15:24