Trilobites once scurried along the ocean floor, just as their distant horseshoe-crab cousins do today. To protect themselves, these ancient insects rolled up into armored balls, much like modern pill bugs do. Most trilobites had compound eyes, but those of Dalmanites were special. They stood up like huge turrets and had lenses that captured the light, giving the trilobite a nearly 360° field of view! In fact, each of Dalmanites' eyes had 770 lenses—more than any other trilobite of its type!

Henry Pratten collected this Dalmanites fossil in 1850, and a relative later donated it to The Field Museum. But it wasn't until 1933 that a curator closely examined the specimen and realized it was a species new to science. Since then, researchers have learned that Dalmanites' eyes are more advanced that previously thought. The thick lenses are made of two different crystals that each bend light differently, but work together to create super-sharp focus. They use optical principles humans didn't understand until the 1600s!

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  • Title: Dalmanites Trilobite
  • Location: USA
  • Type: Specimen
  • Rights: (c) Field Museum of Natural History - CC BY-NC