News Animals

Daddy longlegs look like they have two eyes. That doesn’t count the hidden ones

Two sets of vestigial eyes shed light on the arachnids’ evolutionary history

A macroscopic image of a daddy longlegs spider. Two eyes in the front of the head are clearly visible.

Despite its two-eyed appearance, Phalangium opilio has six peepers. The four extra eyes — leftovers of evolution — shed light on the evolutionary history of daddy longlegs.

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By McKenzie Prillaman

A species of daddy longlegs has been hiding four extra eyes. While the newfound peepers never fully develop, the vestigial organs suggest that this arachnid lineage is about 50 million years older than previously thought, researchers report February 23 in Current Biology.