500 million-year-old “social network” observed in ancient animals

Hyperaxion Mar 5, 2020

Researchers at the universities of Cambridge and Oxford found evidence of life forms that connected through filament networks. The study was published in Current Biology.

The fossilized threads were found in Newfoundland, Canada. They belong to seven different species of organisms called rangeomorphs, scientists believe that such organisms were abundant on Earth 500 million years ago.

For researchers, the discovery of these filament networks was a big surprise: this is the first time that they have found evidence of connections like this between life forms.

500 million-year-old social network
(Credit: Alex Liu).

Some of these threads reach up to four meters in length, and together they formed networks that may have had multiple functions, such as reproduction, nutrition and communication.

Rangeomorphs

Rangeomorphs
Rangeomorphs. (Credit: Jennifer Hoyal Cuthill / University of Cambridge).

The first organisms to live on Earth were single-celled, much like today’s bacteria. Some eventually came together and formed beings that were still microscopic, but multicellular. From the evolution of these organisms came what scientists call proto-animal, a creature of visible size. It was in the Ediacaran period (from 635 to 541 million years ago) that these proto-animals, known as rangeomorphs, appeared.

In a 2014 study published in the Proceedings of the National Academy of Sciences (PNAS), researchers Cuthill and Morris present their reconstruction of the life of rangeomorphs from fossil evidence. Rangeomorphs were creatures from 10 centimeters to 2 meters, with fractal extensions, similar to ferns. For this reason, for a long time, they were thought to be plants.

During the Ediacaran period, when the rangeomorphs had no competitors, they were well-adapted to the environment in which they lived: their bodies full of branches increased the body surface exposed to water, allowing greater absorption of nutrients, carbon and oxygen. For more than 100,000 years, rangeomorphs flourished freely and were the culmination of life on Earth.

One of the first animals on Earth

About 500 million years ago, most of the life on Earth was simple, however, from that period onwards, more complex life forms began to appear, among them the rangeomorphs, possibly one of the first animal species to appear on Earth, which was able to thrive, colonizing the seafloor.

Rangeomorphs had no organs, means of getting around and no mouths. The researchers’ hypothesis is that they survived by absorbing nutrients from the water.

Their inability to move around facilitated the researchers’ work: because the animals did not move, scientists were able to study entire populations in a single fossil record.

(Credit: Alex Liu).

Past studies of these organisms have focused on understanding how they were able to thrive in the time they lived.

“These organisms seem to have been able to quickly colonize the seafloor, and we often see one dominant species on these fossil beds,” said Dr. Alex Liu, one of the scientists responsible for the study. “How this happens ecologically has been a longstanding question – these filaments may explain how they were able to do that.”

Read more: 99 million-year-old cockroach found almost intact

According to the researchers, the filaments had not been identified before because they are very thin, which makes their preservation difficult. The fossils were located at 5 different sites in Newfoundland. Some of them were up to 4 meters, but most of them were between two and 40 centimeters.

A real-life social network

One possibility is that the filaments allowed organisms to share nutrients, something similar to what is observed in modern trees. Another possibility is that they played a reproductive role, just like in today’s strawberries.

“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,” said Liu.

“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. The most unexpected thing for me is the realization that these things are connected. I’ve been looking at them for over a decade, and this has been a real surprise. “

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