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posted by Fnord666 on Monday May 03, @04:25AM   Printer-friendly [Skip to comment(s)]

Billion-Year-Old Fossil Discovered – Reveals Missing Link in the Evolution of Animals:

A team of scientists, led by the University of Sheffield in the UK and Boston College in the USA, has found a microfossil that contains two distinct cell types and could be the earliest multicellular animal ever recorded.

The fossil reveals new insight into the transition of single-celled organisms to complex multicellular animals. Modern single-celled holozoa include the most basal living animals, the fossil discovered shows an organism that lies somewhere between single-cell and multicellular animals.

The fossil has been described and formally named Bicellum Brasieri in a new research paper published in Current Biology.

Professor Charles Wellman, one of the lead investigators of the research, from the University of Sheffield's Department of Animal and Plant Sciences, said: "The origins of complex multicellularity and the origin of animals are considered two of the most important events in the history of life on Earth, our discovery sheds new light on both of these.

[...] The fossil was found at Loch Torridon in the Northwest Scottish Highlands. Scientists were able to study the fossil due to its exceptional preservation, allowing them to analyze it at a cellular and subcellular level.

Journal Reference:
Paul K. Strother, Martin D. Brasier, David Wacey, et al. A possible billion-year-old holozoan with differentiated multicellularity [open] Current Biology (DOI: 10.1016/j.cub.2021.03.051)


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  • (Score: 5, Interesting) by Anonymous Coward on Monday May 03, @08:51AM (2 children)

    by Anonymous Coward on Monday May 03, @08:51AM (#1145619)

    I read the press release, and it looks to me like there's still a fair bit to figure out about the fossil itself, but already this is new information that helps to clarify some things.
    What I didn't like is that the press release didn't say why this is an organism, rather than a symbiotic relation between two different species of mono-cellular life-forms: I think there are plenty of examples of bacteria that sometimes choose to live in a colony.
    Perhaps the paper itself talks about this, but I don't have the background to go through it.

    • (Score: 2, Informative) by khallow on Monday May 03, @02:03PM

      by khallow (3766) Subscriber Badge on Monday May 03, @02:03PM (#1145663) Journal

      What I didn't like is that the press release didn't say why this is an organism, rather than a symbiotic relation between two different species of mono-cellular life-forms: I think there are plenty of examples of bacteria that sometimes choose to live in a colony.

      An example, which probably was around in some form back then was lichen which is a symbiosis of single celled fungus and algae species. Fungus and algae aren't closely related at all and any fossils of them would should substantial differences between the two, no matter what level of development of the lichen.

      Looking at the abstract, a key piece of evidence is that they are seeing this organism at three stages of increasing differentiation of cells of the organism (a label for easy of description): a "naked" stage which has no differentiation in cells, an intermediate stage where cells are starting to differentiate, and a "cyst" stage where the cells of the outer layers have different appearance than cells in the interior and there's a macroscopic structure to the organism. If it were a symbiosis between two species, then the assumption is that one would be able to tell the two apart even at the earliest stages of development, just like with lichen.

      An alternate explanation is that they are looking at multiple species and confusing them with stages of development of a single organism. If so, the cyst symbiosis still would have an early stage, which apparently is not seen in this fossil record.

    • (Score: 1, Informative) by Anonymous Coward on Tuesday May 04, @12:47AM

      by Anonymous Coward on Tuesday May 04, @12:47AM (#1145877)

      What I didn't like is that the press release didn't say why this is an organism, rather than a symbiotic relation between two different species of mono-cellular life-forms

      How I interpreted the second link is that they found multiple specimens and can see that some of them were in an "in-between" stage where the differentiation was half-way. This implies it's the same species which differentiates itself based on some environmental trigger or cell aging timer. If it were composed of two different species, there probably wouldn't be an intermediate stage. Without DNA analysis that's probably hard to confirm, but is rare in living symbiotic relationships unless predation forces one to resemble the other, which is unlikely the case in a microscopic world where familiar optics don't work.

  • (Score: 0) by Anonymous Coward on Monday May 03, @12:20PM (1 child)

    by Anonymous Coward on Monday May 03, @12:20PM (#1145638)

    Once again, scientists overly keen to publish miss the easier explanation: this was just a dwarf Tyrannosaurus rex.

    • (Score: 0) by Anonymous Coward on Monday May 03, @05:36PM

      by Anonymous Coward on Monday May 03, @05:36PM (#1145740)

      Vertically Challenged Tyrannosaurus rex.

  • (Score: 0) by Anonymous Coward on Monday May 03, @02:26PM

    by Anonymous Coward on Monday May 03, @02:26PM (#1145669)

    That the missing link had a plaid-patterned fur coat.

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