Evidence of Early Sponges Discovered in Oman

Scientists studying sedimentary rocks in south Oman have discovered high concentrations of steroids that they believe were produced by ancient, multicelluar animals. The team proposes that the fossilized steroids, which date back 635 million years, were produced by sponges, one of the most basic forms of animal life on Earth.

Sponges (Phylum Porifera) are a diverse group of aquatic animals, with about 5000 known species worldwide. Sponges are primarily marine creatures but there are also a few species of freshwater sponges. Sponges are sessile animals that attach themselves to the sea floor and feed by filtering food from the surrounding water.

The discovery of the ancient sponge steroids in Oman suggests that multi-celled animals were present on Earth 100 million years prior to the Cambrian Explosion, a period in our planet's history when animal life diversified rapidly. The steroids that were discovered are of a type present in the cell membranes of sponges. They function to provide the sponge with structural support.

The research team included scientists from University of California, Riverside, Massachusetts Institute of Technology, and other institutions. The study was headed by Gordon Love, an assistant professor of Earth sciences from MIT. Love hopes to focus future study efforts on analyzing sedimentary rocks that are between 850 and 635 million years old. He hopes that by studying these ancient sediments, he and is colleagues will be able to further their understanding of the first multicellular animals to have inhabited Earth.

Find out more: Researchers Find Earliest Evidence for Animal Life (Eurekalert)

Photo © Love lab / UC Riverside.