RIVERSIDE, Calif. – An international research team of scientists from UC Riverside, the Massachusetts Institute of Technology and other institutions has found the oldest evidence for animals in the fossil record.
The researchers examined sedimentary rocks in south Oman, and found an anomalously high amount of steroids that date back to 635 million years ago, to around the end of the last ice age. The steroids are produced by sponges – one of the simplest forms of multicellular animals.