Researchers believe they have found the earliest known animal footprints, left by a centipede-like creature 570 million years ago; if they’re right, the discovery means that animals were walking on the earth 30 million years earlier than previously thought. Researchers say the fossil shows a track of parallel dots, each about two millimeters in diameter, which may have been pressed into the muddy sand by the tiny feet of one of the earliest complex organisms.
But some experts are not convinced by what they’ve seen. Precambrian paleontologist Nick Butterfield said he was “deeply skeptical,” about the conclusions drawn. “From the description—paired rows of dots—it just doesn’t sound like a trackway…. Centipedes and their ilk shuffle along and leave continuous traces in soft (sub-aerially exposed) sediments—they don’t carefully step ahead, lifting each foot out of the mud to place it exactly in a previously made footprint,” he said [National Geographic News].
In the middle of the Australian outback along a mountain chain called the Flinders Ranges, researchers have discovered a 650 million year old reef that was once underwater. Researchers say the tiny fossils they’ve already found in the ancient reef may be the earliest examples of multicellular organisms ever found, and may answer questions about how animal life evolved.
Researcher Malcolm Wallace explains that the oldest-known animal fossils are 570 million years old. The reef in the Flinders Ranges is 80 million years older than that and was, he said, “the right age to capture the precursors to animals” [The Times]. The first fossils discovered in the reef appear to be sponge-like multicellular organisms that resemble tiny cauliflowers, measuring less than an inch in diameter, but Wallace cautions that the creatures haven’t been thoroughly studied yet. The reef’s discovery was announced at a meeting of the Geological Society of Australia this week.