(CNN) Immobile populations of Earth's earliest animals may have been connected by long filaments in a 500 million-year-old example of a social network, scientists say.

The filaments were discovered in fossils of marine creatures called rangeomorphs in eastern Newfoundland, according to a report published in the journal Current Biology.

Rangeomorphs lived between 571 and 539 million years ago near the end of the Ediacaran period , when communities of complex organisms first started to appear.

Fossils suggest the fern-like organisms lacked mouths, organs or a means of moving, researchers say. The filaments may explain how the organisms were able to reproduce so quickly, said Alex Liu, a paleobiologist at the University of Cambridge and the study's lead author.

"These organisms seem to have been able to quickly colonize the sea floor, and we often see one dominant species on these fossil beds, Liu said in a Cambridge University release . "How this happens ecologically has been a longstanding question -- these filaments may explain how they were able to do that."

What did they do?

The scientists said the filaments were typically two to 40 centimeters long, with the longest measuring more than four meters and appear to have been flexible.

Details of the fossils showing the connecting filaments.

According to the study, similar filaments in existing marine species "typically fulfill stabilization, defense, nutrient transport, or (asexual) reproductive roles" and hypothesized that the same could be true of the rangeomorph structures.

The filaments were so thin that earlier studies missed them, but the Newfoundland fossils are particularly well preserved, according to the report titled "Filamentous Connections between Ediacaran Fronds."

Liu said he had studied rangeomorphs for more than a decade and the filaments were a surprise.

"We've always looked at these organisms as individuals, but we've now found that several individual members of the same species can be linked by these filaments, like a real-life social network," Liu said. "We may now need to reassess earlier studies into how these organisms interacted, and particularly how they competed for space and resources on the ocean floor."