The billion-year-old fossil is possibly the oldest multicellular organism ever discovered

Located in the Northern Highlands of Scotland, Loch Torridon is known for its rich sediments, which are home to countless microscopic fossils, some of which are hundreds of millions of years old. It is therefore located in an archaeological niche that can help understand how the most primitive forms of life evolved into a contemporary biodiversity.

However, a recent discovery in this body of water by a group of researchers from the University of Sheffield (United Kingdom) and Boston College is proving to be largely significant. The microfossil they discovered is not only around a billion years old, but is also seen as a “crucial link” in the evolution of life, as our colleagues at point out.

In very good condition

The new organism, called Bicellum brasieri, is less than 30 micrometers in diameter. It was found in the stone deposits of the old Scottish seabed. This has resulted in a remarkable state of conservation down to the sub-cell level, Science Alert notes.

According to the researchers, this is the first known example of an organism that contains several different cell types. Unlike some organisms that consist of only one cell, Bicellum brasieri has two. Although it is more complex than a unicellular creature, it is not actually multicellular.

A morphology reminiscent of that of holozoa

In any case, this discovery sheds light on the beginnings of complex multicellularity. According to the authors of the article describing the find, published in the journal Current Biology, this is not the first time such an ancient multicellular organism has been identified.

This is the first known example of an organism that contains several different cell types. Bicellum brasieri. Photo credit: Strother et al., Curr. Biol., 2021

Bicellum brasieri, however, is characterized by a morphology that comes close to that of holozoa (holozoa), which is a group of organisms that includes animals and their unicellular parents. “Biologists hypothesized that animals’ origins involved the incorporation and reuse of previous genes that had previously evolved in unicellular organisms,” said paleobotanist Paul Strother of Boston College, Massachusetts, as quoted by Forbes.

More studies in the future

Bicellum brasieri consists of a dense-cell stereoblast surrounded by a layer of sausage-shaped cells and could then provide a better understanding of how unicellular holozoa evolve into more complex multicellular animals. Thanks to this microscopic fossil, the researchers also hope to learn more about certain properties of complex animals. In this regard, they are planning further studies in the hope of finding other nuggets of the same type.

“The origins of complex multicellularity and the emergence of animals are considered to be two of the most important events in the history of life on earth. Our discovery sheds new light on these two aspects,” said his side, welcoming paleobiologist Charles Wellman of the University of Sheffield, reports the BBC.

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