The Baffling Worm That Defies Classification

This simple, worm-like creature is so evolutionary mysterious that scientists struggled for decades to figure out where it belongs on the tree of life. It possesses no brain, no gut, and no anus.

For a long time, researchers were genuinely confused about whether this animal was a primitive worm or a highly degraded mollusk. Recent genetic studies have finally placed it among the early ancestors of modern vertebrates and starfish. Despite their lack of complex organs, these animals survive on the ocean floor by consuming deep-sea clams. They represent a unique branch of life that discarded complexity to thrive in the silent depths of the sea.