This is just a blurb about the finding of evidence of early legs, in the Ediacaran. The tiny “footprints” move back the earliest appearance of legs by 30 million years or so, to around 570 million years ago:
At approximately 570 million years old, this new fossil not only provides the earliest suggestion of animals walking on legs, but it also shows that complex animals were alive on earth before the Cambrian.
Not many macroscopic fossils exist from that time because soft-bodied creatures are not normally preserved.
Babcock says that he is “reasonably certain — not 100 percent” that the fossil was made by a centipede-like arthropod or a leg-bearing worm. A fossil of the animal itself would be more definitive. He is going to continue looking in the same region of Nevada, but that is not the only potential site. Similar fossils might be found in the White Sea area of Russia, South Australia, Newfoundland or Namibia, where body fossils of Ediacaran organisms have been found. Sciencedaily
There are pictures, which support the statement made in the article that there will be “lots of skepticism.” I cannot say that it is definitely a trackway, although it could be. However, if their claims hold, and especially if more tracks are found to confirm such early legs, the notion of the Cambrian “explosion” will become even more tenuous than it presently is.