Ferocious 'penis worms' were the hermit crabs of the ancient seas
These phallus-shaped worms were some of the top predators of the ancient seas, but even they needed protection.
The Cambrian period (543 million to 490 million years ago) brought the first great explosion of biodiversity to Earth, with the ancestors of practically all modern animals first appearing. One of the most feared among them was the penis worm.
Technically known as priapulids — named for Priapus, the well-endowed Greek god of male genitals — penis worms, as they’re commonly known, are a division of marine worms that have survived in the world's oceans for 500 million years.
Their modern descendants live largely unseen in muddy burrows deep underwater, occasionally freaking out fishermen with their floppy, phallus-shaped bodies. But fossils dating back to the early Cambrian show that penis worms were once a scourge of the ancient seas, widely distributed around the world and in possession of extendible, fang-lined mouths that could make a snack out of the poor marine creature that crossed them.
But, fearsome as they were, penis worms themselves were not without fear. In a new study published Nov. 7 in the journal Current Biology, researchers discovered four priapulid fossils that were nestled into the cone-shaped shells of hyoliths, a long-extinct group of marine animals...
Read More: https://www.livescience.com/penis-worms-hermit-shell-behavior