Bilateria
Fossil record

The first evidence of bilateria in the fossil record comes from trace fossils in Ediacaran sediments, and the first bona fide bilaterian fossil is Kimberella, dating to 555 million years ago. Earlier fossils are controversial; the fossil Vernanimalcula may be the earliest known bilaterian, but may also represent an infilled bubble. Fossil embryos are known from around the time of Vernanimalcula (580 million years ago), but none of these have bilaterian affinities. Burrows believed to have been created by bilaterian life forms have been found in the Tacuarí Formation of Uruguay, and were believed to be at least 585 million years old. However, more recent evidence shows these fossils are actually late Paleozoic instead of Ediacaran.
punctuation:no_comma