Courtesy: The Canadian Press
(February 06, Toronto, Sri Lanka Guardian) Scientists have discovered the fossilized bones of what's believed to be the biggest snake ever to have slithered on the planet, a massive reptile that inhabited the rainforest-enshrouded river systems of northern South America about 58 million to 60 million years ago.
Modern-day anacondas have nothing on this baby - a behemoth estimated to have been 13 metres long and weighing in at more than a tonne. Dubbed Titanoboa cerrejonensis, the constricting snake would have been longer than a city bus and equalled Tyrannosaurus rex snout to tail had they lived at the same time.
Titanoboa was the largest non-marine vertebrate on Earth during the epoch following extinction of the dinosaurs 65 million years ago, say the researchers, who report their findings in this week's issue of the journal Nature. "It was fully aquatic, it probably stayed in the water all the time, and like modern anacondas, it probably ate crocodilians," said lead author Jason Head, a world-renowned vertebrate paleontologist at the University of Toronto, Mississauga.
"The biggest modern snakes are the green anacondas, with reliable estimates of about 7 1/2 metres, maybe a little less." Titanoboa's fossilized bones were found in rock layers beneath seams of coal in Colombia's vast Cerrejon open-pit mine, along with the fossils of ancient crocodiles and super-sized turtles that the giant slitherer would have chowed down on.
"They've recovered now about 180 vertebra and ribs that represent at least 28 individual snakes," Head said of University of Florida scientists, who helped excavate the Colombia site. "This snake probably had between 320 to 350 vertebra from the head to the tip of the tail."
But excavating those fossils from the Cerrejon open-pit mine during several expeditions to Colombia was physically demanding, to say the least. "It's very hot and humid, and the coal seams are very thick and you put all that together and the coal itself spontaneously combusts. There's fire coming out of the coal seams and it smells very sulphuric," Jonathan Bloch, curator of vertebrate paleontology at the University of Florida, said from Gainesville."It's hell from the perspective of anyone walking into the mine. But from a vertebrate paleontology perspective, of course, it's complete heaven." The scientists didn't even realize what they'd found until 2007, when they were unpacking fossil specimens in Florida. One of Bloch's graduate students recognized that the vertebra were not from an ancient crocodile as first thought.
"This is a snake - and it's a huge snake," Bloch recalls the student saying. "I was just floored." The discovery was a eureka moment for Head as well, who first saw the fossil during a videoconference chat with Bloch.
"I just about jumped out from my seat," he said, explaining that the largest ancient snake in fossil records was the 11-metre Gigantophis garstini that lived in the Egyptian region 38 million years ago. But it's not just the novel size of the snake that makes the discovery important, said Head.
"The discovery of Titanoboa challenges our understanding of past climates and environments, as well as the biological limitations on the evolution of giant snakes." Based on the size of the creature's bones, he and fellow vertebrate paleontologist David Polly of Indiana University estimated that the mean annual temperature in the equatorial region when it lived had to be between 30 C and 34 C - much hotter than temperatures in modern rainforests.
"So we were actually able to turn the snake into a giant thermometer," said Head. Matthew Huber, an associate professor of Earth and atmospheric sciences at Indiana's Purdue University, said the research provides "a completely new kind of evidence" supporting the still-contested theory that during periods of global warming, the equatorial region would heat up - not just the higher altitudes.
"This says the tropics can get a lot hotter," Huber said from outside Wellington, New Zealand, where he is on sabbatical. "And it also says, so much as you can use the past as an indication, that ... the planet could get several degrees warmer and the tropics are quite capable of supporting a very rich ecosystem."
"So that's why this is really an important issue. It gets into whether the rainforests will survive in the future, whether the coral reefs will survive in the future." During the Paleocene epoch when Titanoboa lived, levels of the greenhouse gas carbon dioxide would have been about 550 to 2,000 parts per million, said Huber, and that's "the same kind of concentrations that a business-as-usual scenario will take us to in the next 100 years or so."
But Head thinks it would be a huge leap to extrapolate conditions 60 million years ago to today's climate change, although "it certainly is cause for concern." And if the planet does get as hot as it was in Titanoboa's time, would we see snakes grow to a similar size? Not likely, he said. "While we're heating up the planet, we're also destroying their habitat."-Sri Lanka Guardian
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