July 17, 2024

Discovery of “Trilobite Pompeii” – forschung.de

Discovery of “Trilobite Pompeii” – forschung.de

Volcanic ash has preserved their bodies down to the finest detail: Paleontologists have reported three-dimensionally preserved fossils that were formed during a volcanic eruption near the coast about 500 million years ago. Now, discoveries in the Atlas Mountains of Morocco have provided new insights into the anatomy of these famous prehistoric aquatic animals. The findings also suggest that fossil treasures could lie in other Pompeii-like deposits around the world, the researchers say.

They are prominent among the extinct creatures in the history of the Earth: from the Cambrian period about 521 million years ago to the end of the Permian period about 251 million years ago, the world’s seas were teeming with trilobites. This is evidenced by countless fossils of representatives of this species-rich group of arthropods (arthropods). Therefore, trilobites are among the best-studied marine animals in the history of evolution. But this does not mean that they have yet revealed all their secrets. As a rule, only their hard shells have been well preserved. On the other hand, the fine structures of the previous body structure have mostly been lost during fossilization. There is still some uncertainty about the characteristics of the delicate body structures and internal organs of trilobites.

New light is now being shed on the microscopic physical structure of prehistoric creatures by the extraordinary discoveries reported by an international research team led by Abderrazak Albani from the University of Poitiers. They come from the so-called Tatlet Formation in the Atlas Mountains of Morocco, which dates back to the Cambrian period, around 500 million years ago. The researchers discovered the amazingly detailed fossils of two species of trilobite there. “I have been studying trilobites for nearly 40 years, but I have never had such a keen sense of looking at living animals. The three-dimensional preservation in this state is truly astonishing,” says co-author Greg Edgecombe from the Natural History Museum in London.

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Furnished with ashes

As the team reported, studies of the material in which the fossils were buried indicate that it is of volcanic origin. Some silicates and other materials indicate that the rock was formed from hot ash that came into contact with salt water. Therefore, the team assumes that the fossils were formed as a result of a flow of lava ash that swept into a shallow area of ​​the sea after a volcanic eruption. When it entered the water, it formed a dense cloud of fine materials that covered and buried all life. About 500 million years ago, trilobites suffered a fate similar to the inhabitants of the Roman city of Pompeii after the eruption of Mount Vesuvius. The researchers explained that in the case of prehistoric aquatic animals, subsequent fossilizations resulted in amazingly detailed fossils that show no deformities or bruises.

In order not to destroy the delicate structures, the team recorded them using computer tomography. Based on the data, they then created virtual X-ray sections, resulting in three-dimensional representations. This revealed how well the animals’ details were preserved: even the hair-like structures running along their limbs could be seen, as could the tiny clams that were once attached to the trilobite shells. The structures of the digestive system were also preserved, the researchers reported. In some cases, the ash appeared to have reached these internal structures.

Video: CT scan results allow the detailed 3D structures of the fossils to be displayed in the model. © Greg Edgecombe

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New insights into trilobite anatomy

Investigations have now also revealed structures not previously discovered in less well-preserved fossils. For example, it was assumed that trilobites had three pairs of head appendages behind long antennae. But as discoveries of small structures in the mouth area showed, there were actually four pairs. For the first time, researchers were also able to discover a structure in prehistoric arthropods that covered the mouth, called the labrum.

“The results also revealed in fascinating detail a set of specialized pairs of legs around the mouth, giving us a clearer picture of how trilobites feed. It also showed that the head and body appendages have inward-directed spine configurations,” says co-author Harry Birks from the University of Bristol. “, similar to those found in horseshoe crabs today.”

In addition to new insights into trilobite anatomy, the team also sees a key message in the study’s findings: “These results demonstrate that marine volcanic ash deposits represent a previously unexplored source of exceptionally preserved organisms.” He writes. “I believe that lava deposits should become a new target of studies because they have an exceptional preservation potential,” says the Albanian lead author. Such findings could lead to important discoveries about the evolution of life on our planet, the scientist said.

Source: University of Bristol, Specialized Article: Science, doi: Science, doi: 10.1126/science.adl4540