These animal sponges might look like your regular kitchen sponges, but they are a bit more than that. They are alive.
Scientists believe that the first sponge that belonged to the phylum Porifera first emerged during the Cambrian period, somewhere between 541 million and 485 million years ago. However, this is an ongoing debate because the geological record during that time is very hard to accurately depict.
Some scientists believe that it wasn't until 760 million years ago, during the Precambrian times, when the animal sponges emerged.
The genetic analysis of the modern sponges suggests their emergence during a Precambrian date, but there is some skepticism because of its poor preservation. According to Science Mag, the study of animal sponges and their emergence is important because the split between the sponges and most other animals (called the Eumetazoa) was a key event in the early history of life on Earth.
A new sponge fossil has recently been discovered in the southern China that dates back to 600 million years ago, which clearly marks the Precambrian period. That sponge fossil is now considered as the oldest known poriferan on Earth.
According to the research team who found the sponge fossil, it is just over 1 millimeter high and wide, which is approximately the size of a small bead. It was found in a phosphorus rich geological formation which is known for its excellent preservation of the animal fossils.
The team says that this newly found specimen is unmistakably sponge like. It has 3 hollow tubes along with a highly porous surface.
This new discovery indicates that the common ancestors of both, the sponges and the Eumetazoa might have lived much earlier than predicted by most of the scientists. Since most of the sponges and eumetazoans differ in many genetic features, this discovery would help the scientists pinpoint the date of the first appearance of the genes that was the key to the evolution and most of the animals living today.
