The Oldest Evidence of Animal Sex Has Been Found, and It’s Mind-Boggling
Scientists have unearthed the oldest fossilized evidence of sexual reproduction and animal locomotion in a remote site in Canada’s Northwest Territories dating back 567 million years to the Ediacaran period, according to a study published on Wednesday in Science Advances. The discovery pushes the origins of animal sex back by 5-10 million years.
The newly discovered fossils were deposited in a fossil layer known as the White Sea assemblage, which has been found in parts of Russia, Asia, and Australia but not in North America previously. These findings offer insights into otherworldly species such as Aspidella, resembling a flying saucer with concentric ring patterns; Dickinsonia, a mouthless pancake that absorbed food through its bottom surface; clusters of tubular Funisia animals, which provide the oldest evidence of sexual reproduction in animals; and an unidentified anchor-shaped lifeform that may represent a new species. These animals lived offshore at depths of about 600 feet.
“We know from rocks in Australia and some famous rock units in Russia that taxa like Dickinsonia could move, and that taxa like Funisia probably reproduce sexually,” said Scott Evans, a curator and professor at the American Museum of Natural History who led the new research. “The cool thing about this study is that we’re finding those same fossils in rocks that are at least seven million years older than the oldest previously known.” He added, “It’s exciting to be able to say they weren’t just around for a blip of time. They were around for a really long period of our history.”
The Ediacaran era (635-541 million years ago) marked the transition from microscopic organisms to larger lifeforms, setting the stage for the Cambrian “explosion” that followed it. However, fossils from this time are rare due to soft-bodied organisms lacking bones or shells conducive to preservation. Some Ediacaran ecosystems have been entombed in stone molds worldwide, offering glimpses of this bizarre lost world. Evans and co-author Justin Strauss of Dartmouth College discovered a new site exposing the first known White Sea fossils in North America.
In 2024, they found remains of Dickinsonia, an organism Evans has studied extensively but never seen in North America before. One particularly evocative find is a tiny organism that likely represents a new species and genus, resembling an “anchor came to life.” The team hopes more specimens will help identify it.
The discovery of Dickinsonia along with another bottom crawler called Kimberella also provides the earliest fossil evidence for animal movement. One intriguing find is a mysterious organism that may represent a new species, similar to an “anchor came to life,” but requires more specimens to confirm.
The team only spent five days at this site last year and plans to return to uncover more details about this assemblage. For example, the emergence of thriving ecosystems in deep offshore waters suggests stability for early animal life compared to shallow coastal regions. Future work could reveal how these environments supported complex life and influenced its evolution.
Key Takeaways
- The discovery pushes back the origins of sexual reproduction by 5-10 million years.
- It offers insights into otherworldly species like Dickinsonia, which was never found in North America before.
- The find provides the earliest evidence for animal movement and sexual reproduction in animals.
- The discovery suggests stability for early animal life in deep offshore waters, setting a precedent for future work.
Originally published at 404media.co. Curated by AI Maestro.
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