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Realistic Images of Earth’s First Animals: The Ediacaran Period

Ediacaran period fauna
Life during the Ediacaran period. Image: Amy King / OpenAI DALL·E

The first complex animals to have ever existed arose during the Ediacaran period (635–540 million years ago). Before then, less complex and single-celled organisms, like sponges and cyanobacteria, populated the Earth. 

Fossils found during an archaeological study in Carmarthenshire, Wales, in the 1970s have recently been dated to 564 million years old. These are some of the oldest animal fossils ever discovered

But what did these fossilized creatures look like? And what other animals from the Ediacaran Period have been discovered?

The Welsh Fossils

first animals
Photographs of the Ediacaran biota from the Llangynog Inlier. Clarke’s study.

The Welsh fossils, otherwise known as the Llangynog fossils, were first discovered in the Llangynog Inlier in 1977 by Professor John Cope. Professor Cope estimated then that these fossils dated back to the Precambrian era, but they had not accurately been dated until now. 

PhD student Anthony Clarke used a method of measuring radioactive decay on volcanic ash layers to determine the approximate age of these fossils. The results confirmed Professor Cope’s estimate. At about 564 million years old, these fossils were found to originate from the Ediacaran period during the Precambrian era. 

The Precambrian era is, as far as we can tell, the earliest years of Earth’s existence. 

The Ediacaran Period

geological periods
ICS International Chronostratigraphic Chart. Available at

This geological period was named after the Ediacara Hills in South Australia, where the first Ediacaran fossils were discovered.

Ediacaran fossils are important for our understanding of how complex life, as we know it, evolved. It is well established that all life comes from a “primordial soup,” but understanding how it evolved from that to where it is now is still poorly understood. Fossils like the Welsh fossils are useful for scientists to better understand the circumstances at which life developed. Furthermore, they can give us an insight into Earth’s geology during that time. 

Ediacaran Mass Extinction

A recurring theme on Earth: with life comes death. The last of the Ediacaran animals died out during the world’s first mass extinction event. Geological studies have found that Earth’s oceans became almost entirely depleted of oxygen, which is the most likely cause of the mass extinction event.

The organisms that survived to start the Cambrian explosion were those that either required no oxygen at all (anoxic) or were somewhere where they didn’t need to compete for oxygen, like burrowed in the soil.  

Ediacaran Fossils

Ediacaran fossils have been found at 40 sites worldwide. Most notably, Newfoundland in Canada, South Australia, Russia, and Namibia.  

Ediacaran animals arose at the end of an ice age and largely populated ocean environments. Many of these animals may have resembled jellyfish, flatworms, and sea anemone. These organisms display biological characteristics similar to those of modern animals, including mobility, heterotrophy, sexual reproduction, and skeletonization.

Based on the descriptions of the animals, provided by, we asked DALL·E to draw what these animals may have looked like. Just ignore the text, AI is not perfect. 


Ediacaran animal. Aspidella
Aspidella. Illustration by A King on DALL·E.

Dickinsonia costata

Edicaran animal Dickinsonia costata
Dickinsonia costata. Image: Amy King / OpenAI DALL·E

Beothukis mistakensis

Ediacaran animal Beothukis mistakensis
Beothukis mistakensis. Image: Amy King / OpenAI DALL·E

Coronacollina acula

Ediacaran animal Coronacollina acula
Coronacollina acula. Image: Amy King / OpenAI DALL·E

Inaria karli

Ediacaran animal Inaria karli
Inaria karli. Image: Amy King / OpenAI DALL·E

Haootia quadriformis

Ediacaran animal Haootia quadriformis
Haootia quadriformis. Image: Amy King / OpenAI DALL·E


Discoveries such as that of the Welsh fossils help us to unravel some of history’s mysteries so that we may better understand our evolution.

If you want to see the Welsh fossils for yourself, they are at the National Museum of Wales in Cardiff.

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