Sponges are just about the simplest animals on the Earth. And they might be the oldest ones we know, too. Adam Maloof and colleagues published a study in Nature Geoscience this week about their find that could push back the oldest known animal life by 70 million years. In Australia, Maloof says, the team found remains of ancient sponges dating to about 650 million years ago.
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 [Discovery News].
