If you’re a fan of bizarre creatures that once roamed the Earth, then Hallucigenia is probably right up your alley. This ancient invertebrate still confounds scientists today with its appearance and mysterious origins. The Hallucigenia lived during the Cambrian period. That’s about 515 to 500 million years ago.
What’s in a name?
We derive its name from its strange anatomy and shape. At the front of its body, it has a pair of tentacles. Next, its long, narrow body was covered in spines and spikes – likely for protection against predators rather than to simply make it look cool.
It also had seven pairs of legs, each with multiple spikes, and a pair of spiky protrusions on its head.
The Hallucigenia’s body ended in a pair of hooks, and it had a thin, flexible skin that may have been used for gliding or swimming. It’s definitely not something you’d want to hug.
With its long spines, claw-like appendages, and worm-like body, some have dubbed it a “nightmare creature.” Scientists are puzzled by this unique anatomy since the creature is not built like animals on Earth today.
You might think because it has legs that it “walks.” But no, it moves in the creepiest way possible.
Instead of walking or crawling on the ground, the Hallucigenia used its long spines to travel across the sea floor. We call this type of locomotion “arm-leggedness,” and we see it in very few creatures today.
Scientists believe that the Hallucigenia was a simple, bottom-dwelling creature that likely lived in shallow seas. Its long, tubular body could have been an advantage to burrow into the sediment or to probe for food.
Researchers once thought it was a primitive crab, but it is not included in the group called Lobopodia since it’s more likely that it’s an early offshoot of a group of animals called Panarthropoda. This would make it an evolutionary “cousin” of modern-day arthropods such as spiders and insects.
Hallucingenia and the fossil record
The fossil record of Hallucigenia serves as a window into the Earth’s past. It provides a glimpse into how our planet’s ecosystems and organisms have evolved over millions of years. And as researchers continue to make new discoveries, it will be interesting to see how scientists piece together the puzzle of this strange creature and learn more about its story.
It might not be the cuddliest creature in history, but the Hallucingenia is no hallucination. It’s one of the planet’s fascinating mysteries born in a time when nothing like a human existed. The Cambrian period saw an explosion in the evolution of new types of creatures. And we know a lot about it because there were many hard-bodied creatures that got preserved in the fossil records (as opposed to being smashed into goo).
Humans would eventually evolve from the first vertebrates (creatures with a backbone) that emerged during this time. But that was going to take tens of millions more years.
Source: “What is hallucigenia?” — BBC Science Focus