Poocastle

Trilobites, a group of extinct marine arthropods, had a hidden third eye — and sometimes even a fourth or fifth, new research suggests.

Paleontologists knew that, like other arthropods such as insects and spiders, these hard-shelled prehistoric sea creatures had a pair of compound eyes, which they used to see during the Paleozoic Era (541 million to 252 million years ago). 

But scientists recently discovered a median eye located in the middle of the long-dead creatures’ foreheads — a common characteristic in arthropods today, according to a study published March 8 in the journal Scientific Reports

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