Elusive builders of nearly perfect hexagonal tunnel fossils were probably small crustaceans—not worms

For more than 170 years, paleontologists have been trying to solve the mystery of what created the strangely uniform hexagonal tunnels found in fossils. In a new study published in Earth Science Reviews, a team of researchers pored over the evidence and concluded that the most likely culprit was a type of arthropod—probably a small crustacean. This challenges a long-standing idea that a worm-like creature may have created the tunnels.

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