Humans! Meet our earliest known ancestor: the Saccorhytus, meaning “wrinkled bag.”
While it may be hard to see the resemblance now, remember that a lot can change in the 540 million years since these creatures were slithering around sediment in the shallow seas of modern day Shaanxi province during the Cambrian explosion.
Researchers at China’s Northwest University and Cambridge University discovered over 40 fossils of these little weirdos and recently published their findings in the journal Nature. About the size of a grain of rice, they had giant gaping mouths with spikes, but curiously, no anus. Instead, they appear to have oozed out waste from slits along their sides.
While that may seem gross, those slits may very well be the precursor to gills. Researchers have determined that the Saccorhytus is the oldest known example of an animal group called the deuterostomes which would eventually come to include anything with a spine, like us or wolf-sized otters.
[Images via Northwest University]
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