A 450-million-year-old fossil of an ancient relative of spiders has been discovered preserved in 3D by fool’s gold.
The new species, which is distantly related to arachnids such as scorpions and horseshoe crabs, was found by a research team lead by the University of Oxford.
It belongs to an arthropods group called megacheirans, which have a large, modified leg at the front of their bodies used to capture prey.
Associate prof Luke Parry, of the university’s department of earth sciences, said that the fossils were “spectacularly preserved”.
#### Discovery of the Fossil
The fossil was found at a site at the famous Beecher’s Trilobite Bed in New York State, a layer of rock containing multiple well-preserved fossils. The animals preserved there lived in a hostile, low oxygen environment. That allowed iron pyrite, commonly known as fool’s gold, to replace parts of their bodies after they were buried, resulting in golden 3D fossils.
#### Insights into Arthropod Evolution
The new species has been called Lomankus edgecombei, after arthropod expert Greg Edgecombe of London’s Natural History Museum. Experts suggest the discovery sheds light on the long-standing riddle of how arthropods evolved the parts on their heads, which can include the antennae of insects and crustaceans, and the pincers and fangs of spiders and scorpions. Unlike other megacheirans, the flexible, whip-like hairs of Lomankus edgecombei suggest the creature was using its frontal appendage to sense the environment, rather than to capture prey.
#### Additional Insight
This discovery provides important insights into the evolution of arthropods and the adaptations that enabled their success. By studying the intricacies of the ancient fossil, researchers can better understand how these creatures developed versatile features in their heads that allowed them to thrive in various environments. As Associate Prof Parry mentioned, the adaptability of their head and appendages acted like a biological Swiss army knife, helping them overcome challenges and ensuring their survival.
