The ancient ancestors of today's harvestmen, the spider-like arachnids, had two sets of eyes, according to a study of a newfound fossil.

Today's harvestmen are referred to as "daddy longlegs" for their eight long legs. As if these creatures weren't scary enough with their dangling legs and weird body structure, University of Manchester found something even more eerie about these species.

A analysis of a newfound, 305-million-year-old harvestman fossil revealed that the ancestors of these spider-like arachnids had not one but two sets of eyes.

"Terrestrial arthropods like harvestmen have a sparse fossil record because their exoskeletons don't preserve well. As a result, some fundamental questions in the evolutionary history of these organisms remain unsolved," co-author Prashant Sharma, a postdoctoral researcher at the American Museum of Natural History, said according to e! Science News. "This exceptional fossil has given us a rare and detailed look at the anatomy of harvestmen that lived hundreds of millions of years ago. What we were also able to establish is that developing modern harvestmen embryos retain vestiges of eye-growth structures seen only in the fossil."

Using X-ray techniques, researchers found that one set of eyes was located close to the center of the head and another on the sides of the head. These ancient arachnids were related to spiders, but were not themselves spiders. In fact, they are more closely related to another arachnid, the scorpion.

"Arachnids can have both median and lateral eyes, but modern harvestmen only possess a single set of median eyes -- and no lateral ones. These findings represent a significant leap in our understanding of the evolution of this group," said author Dr Russell Garwood, a paleontologist in the University of Manchester's School of Earth, Atmospheric and Environmental Sciences, according to Live Science.

Harvestmen don't produce silk and don't have venom. Thus, that old myth about daddy longlegs being the most venomous creature on Earth is just that: a myth. Even if you call a harvestman a daddy longlegs, there's no proof that its venom is especially toxic to humans.

Harvestmen tend to live on the ground in moist areas, such as under logs and rocks. Their long legs explain the "longlegs" part of their nickname, although no one knows for sure where the "daddy" part of it came from. Curiously, scientists point out that there are some species of harvestmen that have short legs!

The long legs of most harvestmen are very important to them as they sense the world around them with their legs, like we do with our ears, nose, tongue and skin. If you try to capture a harvestman, one or more of its legs might fall off. Although losing its legs might help a harvestman escape a predator, it seriously hurts its ability to sense the world around it.