It’s easy to forget that all humans roaming Earth’s surface are walking above an endless number of animal fossils. There’s a good chance, for example, that you’ve walked over your fair share of prehistoric bird skeletons. Or mammoth titanosaur bones. Or, if you’ve ever visited northwestern Canada, what may be the oldest-ever fossil scientists have discovered. As for what the prehistoric beast could be? It’s probably a sponge.
Elizabeth Turner, a sedimentary geologist at Laurentian University in Sudbury, Canada, led the team that described the possible fossil. The team recently published its findings in the journal Nature, although Turner collected the fossils from ancient microbial reefs preserved in the rocks of Canada’s remote Northwest Territories during her graduate studies back in the 1990s.
According to Turner she examined slices of the rocks she collected and saw branching networks of crystalline tubes. She later realized these tubes looked similar to the internal “scaffolding” of modern-day horny sponges and began exploring a possible relation. For those unfamiliar, horny sponges are—we’ll quote here verbatim from Merriam-Webster—”sponges lacking spicules but having a spongin skeleton that is more or less horny.” (Spicules are pointy structures on sponges that have a crystalline appearance and consist of simple spines.)
In the Nature video above we see Turner’s possible sponge fossil. As the narrator notes, the 860-million-year-old fossil, if it is indeed one, would represent the oldest animal known to humankind; destroying the previous record held by a 550-million-year-old digestive tract from the Nevada desert.
If this imprint is indeed a horny sponge fossil and not a structure crystals left behind, “animals emerged long, long before the first appearance” of traditional animal fossils, Turner said in a Nature press release. “That would mean there’s a deep back history of animals that just didn’t get preserved very well.”
nature video
