Oldest Fossil Evidence for Animals Found

Hymeniacidon sp. Photograph: Jane Fromont, WA Museum

From Live Science:

The oldest fossilized evidence of animals has been unearthed in Oman and reveals that tiny sea sponges were abundant 635 million years ago, long before most of the planet's other major animal groups evolved, according to a new analysis.

This early life hardly looked like us, but some of the so-called demosponges can be sizable today. Demosponges still make up 90 percent of all sponges on Earth and 100 percent of Earth's largest sponges, including barrel sponges, which can be larger than an old-style phone booth.

The ancient demosponges — probably measuring across no more than the width of a fork tine — were pinned down via fossilized steroids, called steranes, which are characteristic of the cell membranes of the sponges, rather than via direct fossils of the sponges themselves.

Read more ....