Twisting and turning atop the muddy ooze, the acorn worm (class Enteropneusta) is an unassuming worm-like animal that has a surprising connection to Earth’s climate. Named for their acorn-shaped front end, enteropneusts are actually more closely related to humans than to worms. They have a rudimentary nerve cord that is similar to ours, and they breathe oxygen using structures similar to a fish's gills. A constant rain of particles connects the ocean's surface to deep-sea communities far below.

Unveiling the deep, the Acorn Worm's evolutionary secrets

Your newest #WormCrushWednesday—the deep-sea worm, Allapasus aurantiacus. ⁠ ⁠ Acorn worms are known to biologists as “enteropneusts” (pronounced ‘entero-noosts’—the ‘p’ is silent). They belong to a small group of animals known as the hemichordates, which are closely related to the chordates (animals with backbones). ⁠ ⁠ Acorn worms have no bones, no eyes, and no brain. Their bodies have three main parts—a long, worm-like trunk, a wide collar that surrounds a mouth, and a large proboscis that fil

Acorn Worm Facts and the Regeneration of Human Body Parts