August 18, 2010

Remains Of 650 Million Year Old Animal Life Discovered

Scientists have found fossils which suggest that animal life appeared on Earth millions of years earlier than previously thought, according to Princeton University and National Science Foundation (NSF) press releases published Tuesday.

The fossils, which were described as "shelly" and are believed to have bellowed to primitive sponge-like creatures that dwelled in ocean reefs, were unearthed below 635 million year old South Australian glacial deposits. According to the NSF, those sponge-like creatures lived approximately 650 million years ago, and as such the discovery represents "the earliest evidence of animal body forms in the current fossil record, predating other evidence by at least 70 million years."

The discovery was made by Princeton geosciences professor Adam Maloof and university graduate student Catherine Rose, who were studying the ice age that marked the end of the Cryogenian period. Joining Maloof and Rose on their expedition were geosciences professor Frederik Simons, former postdoctoral fellow Claire Calmet, Nan Yao and Gerald Poirier of the Princeton Institute for the Science and Technology of Materials (PRISM), Douglas Erwin of the Smithsonian Institution, and Robert Beach, Basar Girit, Wesley Rozen, Sigfus Briedfjord and Aleksey Lukyanov of Situ Studio. The findings of the research, which was funded by the NSF, appear in the August 17 issue of Nature Geosciences.

The researchers claim that the Australian fossils "provide the first direct evidence that animal life existed before--and probably survived" the Marinoan Glaciation. The event, which is also known as "Snowball Earth," is a hypothesized condition that saw the entirety of the Earth's surface becoming frozen or nearly frozen approximately 650 years ago, at the end of the Cryogenian Age.

"We were accustomed to finding rocks with embedded mud chips, and at first this is what we thought we were seeing," Maloof said in the Princeton University press release. "But then we noticed these repeated shapes that we were finding everywhere--wishbones, rings, perforated slabs and anvils."

"By the second year, we realized we had stumbled upon some sort of organism, and we decided to analyze the fossils," he added. "No one was expecting that we would find animals that lived before the ice age, and since animals probably did not evolve twice, we are suddenly confronted with the question of how some relative of these reef-dwelling animals survived the 'snowball Earth.'"

Furthermore, the NSF reports that the researchers unearthed "controversial fossils of soft-bodied animals that date to the latter part of the Ediacaran period between 577 and 542 million years ago." Before the discovery, the oldest previously discovered fossils of hard-bodied animals were dated back to roughly 550 million years ago, according to the pair of press releases.

The impact on the fossil record could be huge, according to H. Richard Lane of the NSF's Division of Earth Sciences. "These scientists have found that animals may have appeared on Earth 90 million years earlier than previously known"¦ This is comparable to resetting modern times to begin during the late Cretaceous," he said.


Image 1: Stromatolite column of bacterial mats in Australia; sponge fossils are between stromatolites. Credit: Adam Maloof

Image 2: Image of limestone rock containing fossils; fossil of interest is highlighted in blue using automated image tracing software. The serial grinding process created nearly 500 such images that the scientists stacked and autotraced to create a 3-D model. Credit: Maloof Lab/Situ Studio


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