‘890m-year-old sponge fossils’ could be earliest animal life

9th August, 2021.      //   General Interest  // 

dc5c5dcb82cb2898867c9896e1b1a351

A research that detects sponge-like structures among ancient reefs suggests that sponges may have existed in waters up to 890 million years ago.

If the results are confirmed, they might be the oldest known fossilised animal body, predating the next-oldest undisputed sponge fossils by about 350 million years, according to one expert.

Sponges are basic creatures that evolved during the early Neoproterozoic period, according to genetic evidence from contemporary sponges (1,000 million to 541 million years ago).

However, there aren’t many fossilized sponge bodies during this time period.

Professor Elizabeth Turner of Laurentian University in Ontario, Canada, looked at rock samples from 890-million-year-old reefs formed by calcium carbonate-depositing bacteria in northwestern Canada.

She discovered branching networks of tube-shaped structures that held calcite crystals and were encircled by them.

The fibrous skeleton found in horny sponges, a contemporary variety utilized to produce commercial bath sponges, was discovered to be quite similar to these structures.

They looked a lot like formations seen in calcium carbonate rocks that were supposed to have been formed by the decomposition of horny sponge bodies.

Prof Turner believes the structures are the fossilized remnants of horny sponges that lived on, in, and around calcium carbonate reefs 90 million years ago, before Earth’s oxygen levels rose to levels considered to be essential for animal life to thrive.

If the structures are regarded as sponge body fossils, the discoveries might suggest that early animal development happened independently of this oxygenation event and that early animal life survived severe cold ages that occurred between 720 million and 635 million years ago.

According to the report published in Nature, “If vermiform microstructure is in fact the fossilised tissue of keratose sponges, the material described here would represent the oldest body-fossil evidence of animals known to date, and would provide the first physical evidence that animals emerged before the Neoproterozoic oxygenation event and survived through the glacial episodes of the Cryogenian period.”