HALLUCIGENIA
When this ancient arthropod from the middle Cambrian period was discovered scientists were baffled, nothing like it had ever been seen before. It appeared to walk on rigid, stilt-like structures and have odd fleshy appendages running along its back.
It wasn’t until much later that scientists actually discovered the had been looking at Hallucigenia upside down and back to front. The rigid spikes actually ran along its back and the fleshy appendages were its limbs. It was then recognised as a relative of modern ocean dwellers, velvet worms.
Like many of its Cambrian counterparts, Hallucigenia was discovered in the Burgess Shale in Canada by Charles Doolittle Walcott. Hallucigenia got its name due to its bizarre appearance, almost as if it were a hallucination.
Fossils range in size from around 0.5 to 2.5 cm long. At first, Hallucigenia’s head seemed featureless, with nothing but a dark stain on the rock where it was, yet its thought to have had primitive eyes and a mouth with radial teeth. One fossil appears to show decayed content from the animals gut that would’ve been squeezed put upon its burial…Not too nice.
Hallucigenia is a truly peculiar animal, it’s still debated even today that it’s not an individual animal but part of a larger one, like that of Anomalocaris which was pieced together from its appendages that were thought to be shrimp and its mouth mistaken for a jellyfish. Yet the Cambrian period is notorious for its strange species, the Cambrian explosion saw an eruption in the diversity of life, leading to evolutionary dead ends and experiments, some of which have led to us today.
