These fossils show a female flea that roamed the earth between 125 million and 165 million years ago. The fleas grew to be nearly an inch long and could have fed on the blood of dinosaurs.

Large fleas up to an inch long roamed the earth more than 150 million years ago and had mouth parts strong enough to puncture the hides of some dinosaurs, a Kansas University researcher has found.

Michael Engel, a KU entomologist, is a co-author of the study published online Wednesday in the journal Nature.

“They were quite the beasts,” Engel said. “And certainly not anything you’d want crawling around on your pets.”

While the parasites could have fed on the blood of smaller mammals or birds, dinosaurs could have easily been a target, too. The fleas’ mouth parts were equipped with a little siphon and were long and serrated, he said.

“They’re like little saw blades,” Engel said. “Whatever this thing was trying to get through, it was well-equipped to work its way through it.”

The fossils range from 165 million to 125 million years old and were found primarily in China.

Before these fossils were found, the oldest known fleas were about 40 million years old, Engel said.

The fossils are also scientifically important because they help show how fleas evolved over time. They show about half of the traits of modern fleas and half of the traits of their primitive ancestors, he said. For example, the fossilized fleas lack the large legs that modern-day fleas use for jumping.

“They’re halfway there,” Engel said.