Thanks to new fossil evidence out of Greenland, scientists have finally solved the mystery of what exactly the mouth of a unique group of ancient arthropods looked like.

Pambdelurion was an arthropod ancestor with 12 legs and a matching row of flaps running down each side of its body, along with spiny appendages for grasping prey attached to its head. But incomplete fossils left researchers guessing as to what Pambdelurion's mouth looked like.

Some suggested it resembled the mouth of Anomalocaris -- at three feet in length, the largest sea predator from the Cambrian Period. Others argued its mouth looked like those of penis worms, a subset of marine worms called priapulids.

The latest fossil evidence, excavated from dig sites in North Greenland, suggest the latter analogy is most accurate.

"The mouth is a spitting image of the Sarlacc from Star Wars," explained Jakob Vinther, a paleontologist at Bristol University, explained in a news release.

Sarlacc is the fearsome creature whose crater-like mouth, lined with rows of spike-like teeth, is found among the Tatooine sand dunes in Return of the Jedi.

The newest Pambdelurion specimens were much better preserved than previous fossils. Scientists determined them to be 520 million years old.

The findings -- detailed in the journal Paleontology -- suggest, in addition to penis worms, Pambdelurion is closely related to roundworms, horsehair worms and mud dragons.

"What we see in these arthropod ancestors is the same kind of mouth as in penis worms -- right down to details of the rings of teeth and plates -- and we argue that this was present in the last common ancestor," said study co-author Greg Edgecombe, a researcher at London's Natural History Museum.

"It seems as if nowhere was safe back in the Cambrian," concluded co-author Fletcher Young, a former Bristol grad student. "No matter whether you lived in the water column or on the seafloor there was a big, ugly beast that would devour you."