Found 1 billion year old fossil the oldest known.

[shunyadragon]

Source: https://www.sciencealert.com/ancient-fossil-could-be-the-oldest-multicellular-animal-on-record

1 Billion-Year-Old Fossil Could Be The Oldest Multicellular Animal on Record

MICHELLE STARR
30 APRIL 2021

A teeny tiny fossil found in the Scottish Highlands could be a missing link in the evolutionary history of animals.

Dated to around a billion years ago, the microfossil shows evidence of two distinctly different types of cells, and it seems to belong to an ancient organism somewhere between unicellular and multicellular animals. This makes it possibly the oldest fossil of its kind on record, a discovery that could provide insight into how and where animal life evolved.

"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," said palaeobiologist Charles Wellman of the University of Sheffield in the UK.

"We have found a primitive spherical organism made up of an arrangement of two distinct cell types, the first step towards a complex multicellular structure, something which has never been described before in the fossil record."

The fossils - measuring under 30 micrometers across - were found in the Diabaig Formation at Loch Torridon, an assemblage containing microfossils from a lacustrine setting dating to 1 billion years ago. The stone deposits from the ancient lakebed have kept the fossils in a remarkable state of preservation, right down to the subcellular level.

The new organism, named Bicellum brasieri, was preserved so well in multiple fossils, that its structure was clearly visible. In its mature form, it appears to have consisted of a tiny sphere of tightly packed, roughly spherical cells (known as a stereoblast), surrounded by a differentiated outer single layer of elongated, sausage-shaped cells.

Bicellum brasieri. (Strother et al., Curr. Biol., 2021)

Two populations, however, show a mixture of cell types throughout the stereoblast. The researchers have interpreted this as a more juvenile form of the organism during the process of differentiation, with the sausage cells developing and in the process of migrating to the exterior of the stereoblast.

Other multicellular organisms from around the same time have been identified, including fungus and algae, but the morphology of Bicellum, the researchers said, is more consistent with Holozoa, the group that contains animals and their closest unicellular relatives.

© Copyright Original Source

[rogue06]

Source: https://www.sciencealert.com/ancient-fossil-could-be-the-oldest-multicellular-animal-on-record

1 Billion-Year-Old Fossil Could Be The Oldest Multicellular Animal on Record

MICHELLE STARR
30 APRIL 2021

A teeny tiny fossil found in the Scottish Highlands could be a missing link in the evolutionary history of animals.

Dated to around a billion years ago, the microfossil shows evidence of two distinctly different types of cells, and it seems to belong to an ancient organism somewhere between unicellular and multicellular animals. This makes it possibly the oldest fossil of its kind on record, a discovery that could provide insight into how and where animal life evolved.

"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," said palaeobiologist Charles Wellman of the University of Sheffield in the UK.

"We have found a primitive spherical organism made up of an arrangement of two distinct cell types, the first step towards a complex multicellular structure, something which has never been described before in the fossil record."

The fossils - measuring under 30 micrometers across - were found in the Diabaig Formation at Loch Torridon, an assemblage containing microfossils from a lacustrine setting dating to 1 billion years ago. The stone deposits from the ancient lakebed have kept the fossils in a remarkable state of preservation, right down to the subcellular level.

The new organism, named Bicellum brasieri, was preserved so well in multiple fossils, that its structure was clearly visible. In its mature form, it appears to have consisted of a tiny sphere of tightly packed, roughly spherical cells (known as a stereoblast), surrounded by a differentiated outer single layer of elongated, sausage-shaped cells.

Bicellum brasieri. (Strother et al., Curr. Biol., 2021)

Two populations, however, show a mixture of cell types throughout the stereoblast. The researchers have interpreted this as a more juvenile form of the organism during the process of differentiation, with the sausage cells developing and in the process of migrating to the exterior of the stereoblast.

Other multicellular organisms from around the same time have been identified, including fungus and algae, but the morphology of Bicellum, the researchers said, is more consistent with Holozoa, the group that contains animals and their closest unicellular relatives.

© Copyright Original Source

If true that would require a whole new look at the Barren Billion. Or at least the last 200 million years of it.

[rogue06]

The paper, A possible billion-year-old holozoan with differentiated multicellularity can be read by following the hyperlink. The Abstract/Summary is below

Sediments of the Torridonian sequence of the Northwest Scottish Highlands contain a wide array of microfossils, documenting life in a non-marine setting a billion years ago (1 Ga). Phosphate nodules from the Diabaig Formation at Loch Torridon preserve microorganisms with cellular-level fidelity, allowing for partial reconstruction of the developmental stages of a new organism, Bicellum brasieri gen. et sp. nov. The mature form of Bicellum consists of a solid, spherical ball of tightly packed cells (a stereoblast) of isodiametric cells enclosed in a monolayer of elongated, sausage-shaped cells. However, two populations of naked stereoblasts show mixed cell shapes, which we infer to indicate incipient development of elongated cells that were migrating to the periphery of the cell mass. These simple morphogenetic movements could be explained by differential cell-cell adhesion. In fact, the basic morphology of Bicellum is topologically similar to that of experimentally produced cell masses that were shown to spontaneously segregate into two distinct domains based on differential cadherin-based cell adhesion. The lack of rigid cell walls in the stereoblast renders an algal affinity for Bicellum unlikely: its overall morphology is more consistent with a holozoan origin. Unicellular holozoans are known today to form multicellular stages within complex life cycles, so the occurrence of such simple levels of transient multicellularity seen here is consistent with a holozoan affinity. Regardless of precise phylogenetic placement, these fossils demonstrate simple cell differentiation and morphogenic processes that are similar to those seen in some metazoans today.

including a "graphical abstract":

fx1.jpg

[shunyadragon]

The paper, A possible billion-year-old holozoan with differentiated multicellularity can be read by following the hyperlink. The Abstract/Summary is below

Sediments of the Torridonian sequence of the Northwest Scottish Highlands contain a wide array of microfossils, documenting life in a non-marine setting a billion years ago (1 Ga). Phosphate nodules from the Diabaig Formation at Loch Torridon preserve microorganisms with cellular-level fidelity, allowing for partial reconstruction of the developmental stages of a new organism, Bicellum brasieri gen. et sp. nov. The mature form of Bicellum consists of a solid, spherical ball of tightly packed cells (a stereoblast) of isodiametric cells enclosed in a monolayer of elongated, sausage-shaped cells. However, two populations of naked stereoblasts show mixed cell shapes, which we infer to indicate incipient development of elongated cells that were migrating to the periphery of the cell mass. These simple morphogenetic movements could be explained by differential cell-cell adhesion. In fact, the basic morphology of Bicellum is topologically similar to that of experimentally produced cell masses that were shown to spontaneously segregate into two distinct domains based on differential cadherin-based cell adhesion. The lack of rigid cell walls in the stereoblast renders an algal affinity for Bicellum unlikely: its overall morphology is more consistent with a holozoan origin. Unicellular holozoans are known today to form multicellular stages within complex life cycles, so the occurrence of such simple levels of transient multicellularity seen here is consistent with a holozoan affinity. Regardless of precise phylogenetic placement, these fossils demonstrate simple cell differentiation and morphogenic processes that are similar to those seen in some metazoans today.

including a "graphical abstract":

fx1.jpg

Thank you!!!