Canadian Researchers Find Hundreds Of Million Year Old Fossil, Similar To A Mediterranean Bath Sponge

Illustration of northwestern Canada. (Wikimedia Commons/Cameron Hayne)

JAKARTA - A fossil found in the rugged mountains of northwestern Canada could provide a glimpse into the beginnings of life for a simple animal on Earth, a marine sponge that inhabited ancient coral reefs formed from bacteria 890 million years ago.

A Canadian researcher said on Wednesday, July 28, that the fossil, dating from a time called the Neoproterozoic Period, allegedly shows the distinctive microstructure of a marine sponge body built similar to the species living today, the Mediterranean bathing sponge, or Spongia officinalis.

If this interpretation is correct, this discovery would be the oldest fossil of animal life dating back about 300 million years, as quoted by Reuters.

"The earliest animals that emerged evolutionarily may have resembled sponges. This is not surprising, given that sponges are the most basic type of animal both today and in the fossil record," said geologist Elizabeth Turner of Laurentian University in Canada, who carried out the study and published it in journal 'Nature'.

When people think of animals, sponges may not immediately come to mind. But sponges, aquatic invertebrates that live attached to the ocean floor and have soft, porous bodies with internal skeletons, are one of the most successful groups of animals.

Illustration of the northwestern region of Canada. (Wikimedia Commons/berkeley_geography@Flickr Commons)

"They don't have nervous, digestive and circulatory systems. They have amazing water-pumping machines, produced by specialized cells, which they use to move seawater through their bodies to filter food," Turner said.

Some sponges have skeletons made of microscopic rods of quartz or calcite. Others have a skeleton made of a tough protein called spongin that forms a complex three-dimensional network that supports the soft tissues of animals. Canadian fossils represent the latter type, called horn sponges.

"This is a preserved 3-D spongin meshwork relic structure and it's very distinctive," Turner said.

This structure, seen under a microscope, consists of tiny tubes that branch and rejoin to form a webbing. The sponge's body measures approximately four-tenths of an inch (1 cm). Turner said the sponges appeared to have lived in cavities just below the coral's surface and in surface basins.

If these fossils really do show a type of sponge, their age would have seen the first animals on Earth evolve, before two important events leading up to animal life.

One of these is an episode in the planet's history when the amount of oxygen in the atmosphere greatly increased, between about 830 and 540 million years ago. The other is a very cold time when Earth may have been encased in ice or at least partially frozen, between about 720 and 635 million years ago.

To note, the fossils predate about 350 million years which is the oldest known sponge fossil. Turner noted, genetic research shows that sponges first appeared around the time these fossils came from.