- Scientists have discovered the world's oldest known animal fossils, dating to 650 million years ago.
- The fossils, likely sponges, push back the fossil record for animals by about 70 million years.
- The sponges existed before, and probably after, a severe "Snowball Earth" event that covered much of the globe in ice.
Animals have been on Earth for at least 650 million years, suggest recently found primitive sponge fossils from South Australia.
This discovery pushes back the fossil record for animals by about 70 million years, according to a new study published in the journal Nature Geoscience.
The prior oldest known hard-bodied animals were reef-dwelling organisms called Namacalathus, which date to approximately 550 million years ago. Disputed remains for other possible soft-bodied animals date to between 577 and 542 million years ago.
The even more advanced age of the newly found sponge fossils provides direct evidence that animal life existed before the severe "Snowball Earth" event. The episode marked the end of Cryogenian Period 635 million years ago and left much of the globe covered in ice.