Prehistoric Penis Worm Priapulids Invented the Lifestyle of Hermit Crabs, Study Says

Many species have weird physical structures, and among them are the phallus-shaped priapulids. Although they had genital-like bodies, the specified creatures are the most ferocious predators under the prehistoric waters. Discovered between 543 to 490 million years ago during the Cambrian period, the 'penis worms' belonged to the massive explosion of biodiversity on our planet. The creatures that appeared and evolved during this time on Earth varied from their position on the food chain, and among them was the unexpected underwater terror that looked exactly like a man's genitalia.

Priapulids: Predators of Cambrian Period

Priapulids were active members of the animal kingdom during their existence back in the Cambrian period. They were named after the mythical god of ancient Greece known as Priapus. Based on the stories, Priapus is the deity for male genitals, and this was the sole reason to bestow the fitting name to the species.

The marine worms were able to thrive under the seas of prehistoric Earth for a span of 500 million years. Throughout evolutionary history, the priapulids developed and coped with the changing conditions of the oceanic bodies. In the present day, their descendants are still living under the muddy burrows of the seafloor. They frequently surprise or upset many fishermen who unintentionally catch them and other fishes due to their familiar shape.

Although the strange appearance of the priapulids seems whimsical for many, fossil records imply that they had been good at terrorizing the depths of the ancient seas. The familiar shape of the species could lure their prey due to its vulnerable form. Once they chart their unfortunate victim, fang-lined mouths of the penis worms will devour the prey.

Phallus-Shaped Worms are First Hermits of the Seas

A new study states that the intimidating Eximipriapulus predators were found to have used protection despite their monstrous ability over their prey. It was discovered that the prehistoric worms had a habit of hiding inside the conical shells of a separate species called the hyoliths. Moreover, many of the creatures were unearthed with their fossils inside the same shells, suggesting that their choice had been appropriated as their homes, similar to what the modern-day hermit crabs do. It supports the theory of the authors that the priapulids may have been the inventors of the 'hermit' approach and passed on the underwater lifestyle to other lineages, such as the crustaceans.

Durham University paleontology expert and co-author of the study Martin Smith said in a Live Science report that their findings confirmed the possibility of the priapulids acknowledging the shells as their own habitat.

The hermit penis fossils that were examined in the study were discovered from southern China's biodiverse Guanhan deposits. The underwater region was able to protect the remains of the species in a span of over 500 million years. Besides the priapulids, the fossil hoard contains many types of hardened shells, bone fragments, and other soft structures of various species. The study was published in the journal Current Biology, titled "A 'hermit' shell-dwelling lifestyle in a Cambrian priapulan worm."

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