A 450-million-year-old spider fossil found in fool’s gold

Newly discovered 450-million-year-old fossilized arthropods offer extraordinary insight into the evolution of ancient creatures, according to research published in the journal Current Biology. The species, named Lomankus Edgecombei, was unearthed at the famous Beecher’s Trilobite Bed in New York State, a site known for its exceptional preservation conditions that have produced fossils with intricate detail.

Lomankus Edgecombei is a distant relative of modern horseshoe crabs, scorpions and spiders. Belonging to an extinct class of predatory arthropods known as megacheirans, this discovery shows that the group was still evolving 450 million years ago. Megacheirans flourished during the Cambrian period (538-485 million years ago) and mostly became extinct during the Ordovician period (485-443 million years ago). Finding

Lomankus Edgecombei is a valuable piece in the puzzle of arthropod evolution. The fossil was preserved in three dimensions thanks to a unique natural process involving iron pyrite, also known as “fool’s gold,” which found its way into the remains after the animal’s death. Iron pyrite occupied empty spaces and reproduced animal shapes, ensuring exceptional retention of the golden luster. This process results from the specific conditions of low oxygen and high iron content in Beecher’s Trilobite Bed. Luke Parry, professor of paleobiology at the University of Oxford and lead author of the study, began studying fossils when he was a postdoctoral research fellow at the Yale Peabody Museum. He was “amazed” by how good it was

“In addition to their beautiful and striking golden color, these fossils are spectacularly preserved; “after washing, the rocks seem to come to life and escape,” Parry claimed, according to El Cronista. He added: “They look like they could just get up and run away.” Exceptional conservation has enabled scientists to study the anatomy of Lomankus Edgecombei in unprecedented detail.

The Beecher trilobite deposit contains a large representation of fossil organisms in perfect condition because the iron pyrite retained the shape of its bodies after being buried in the sediment. The low-oxygen environment in which Lomankus Edgecombei lived allowed the pyrite to quickly replace its delicate anatomical features before they decayed. Luke Parry explained that pyrite is formed by the action of sulfate-reducing bacteria, which, in the absence of oxygen, break down organic matter, producing hydrogen sulfide, which can then react with iron to form pyrite.

The anatomy of Lomankus Edgecombei allows us to understand how the appendages on the heads of arthropods evolved into the antennae, pincers and fangs now found in insects, crustaceans and arachnids. Megacheirans, including Lomankus edgecombei, were characterized by a large frontal appendage used to capture prey. However, Lomancus had a unique adaptation: its appendages bore three long, flexible tendrils resembling a whip. These features are similar to those of living arthropods, suggesting that the large appendage is equivalent to the antennae of insects and the snouts of spiders and scorpions.

Lomancus Edgecombei used its anterior appendage to perceive its surroundings rather than to capture prey, indicating a very different lifestyle from its older Cambrian relatives, who used their appendages to capture prey. This suggests that Lomankus edgecombei probably relied on its anterior appendage to detect and search for food in a dark, low-oxygen environment.

The unique conservation process has resulted in spectacular three-dimensional gold fossils that can be scanned to reveal hidden details about their anatomy. Due to the density of the pyrite, researchers had to use advanced techniques such as computed tomography to study the anatomical details of the pyrite.

Lomancus Edgecombei. CT scanning involves rotating the specimen to take thousands of X-ray images that allow the fossil to be reconstructed in three dimensions.

According to The Independent, Luke Parry said: “We’re getting almost a full view of their anatomy.” Specimens of Lomankus Edgecombei were buried alive in turbidites, ensuring rapid burial without decomposition, probably due to the huge piles of sediment carried by turbidity currents. These turbidity currents created special conditions that allowed arthropods to pyritize from the outside in.

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Co-corresponding author Professor Yu Liu of Yunnan University in China said: “These beautiful new fossils show a very distinct plate on the underside of the head, associated with the mouth and surrounded by large appendages,” as reported by The Independent. The arrangement of features on the head of Lomankus Edgecombei was similar to that of living arthropods, suggesting evolutionary links.

Greg Edgecombe of the Natural History Museum in London is considered one of the world’s leading experts on arthropods. The new species honors him in its nomenclature. The study confirms the importance of this discovery for the scientific community.

Steve Brusatte, professor of palaeontology and evolution at the School of GeoSciences at the University of Edinburgh, said Lomankus Edgecombei was an extraordinary find. “It’s amazing, as if the entire body of this little arthropod turned into gold jewelry,” he said, according to Science. “And that makes the fossil not only beautiful, but also important from a scientific point of view.”

The discovery of Lomankus Edgecombei provides valuable clues to better understand how arthropods developed frontal appendages to control their environment and capture prey. These well-preserved fossils provide new insight into the anatomy of megacheirans and help prove how the arthropods developed their appendages.

There are now more species of arthropods on Earth than any other group of animals, said Luke Parry, as reported by Science. “The key to this success is their highly adaptable head and its appendages, which have adapted to different challenges like a biological Swiss Army knife.”

Thanks to these unique discoveries, we can continue to learn about the evolution of life in ancient oceans and the delicately preserved anatomical features. The fossil offers a portal into the natural world from 450 million years ago, providing clues about what life was like on Earth at that time.

Sources: Popular Science, Cosmos, Discover Magazine, El Nuevo Día, The Independent, Mundo Deportivo, Milenio.com, Scienze Notizie, Yahoo News, Science, ScienceAlert, El Cronista

This article was written in cooperation with Alchemiq, a company dealing with generative artificial intelligence