Paleontologists have discovered fossils of an ancient bug species that has been encased in fool’s gold for the last 450 million years in central New York. This newly identified species, Lomankus edgecombei, is related to today’s horseshoe crabs, scorpions, and spiders. It lacked eyes and had small front appendages that were adapted for digging in the dark ocean sediments of an era when present-day New York was underwater.
Paleontologists have discovered fossils of an ancient bug species that has been encased in fool’s gold for the last 450 million years in central New York.
This new species, Lomankus edgecombei, is a distant relative of modern horseshoe crabs, scorpions, and spiders. It was eyeless, and its tiny front appendages were ideally designed for sifting through dark ocean sediment when what is now New York was a sea.
Interestingly, Lomankus is bright gold, owing to layers of pyrite—commonly known as fool’s gold—that have seeped into its remains.
This golden hue serves a purpose beyond mere aesthetics. The pyrite, found in a fossil-rich region near Rome, New York, called “Beecher’s Bed,” played a crucial role in preserving the fossils by gradually replacing the soft tissue structures of Lomankus before they decomposed.
“These extraordinary fossils reveal how the quick replacement of fragile anatomical features by pyrite, before decay occurs, successfully preserves essential evidence of evolutionary history in the oceans from 450 million years ago,” explained Derek Briggs, the G. Evelyn Hutchinson Professor of Earth and Planetary Sciences in Yale’s Faculty of Arts and Sciences.
Briggs is a co-author of a recent study published in Current Biology that details this new species, and he also serves as a curator at the Yale Peabody Museum.
Briggs and his colleagues noted that Lomankus, which is part of an extinct group of arthropods known as Megacheira, holds evolutionary importance in various ways.
Similar to other Megacheirans, Lomankus showcases an arthropod with a versatile head and specialized appendages—similar to the claws of a scorpion or the fangs of a spider. Specifically, Lomankus features front appendages with three long, flexible, whip-like flagella, which may have been utilized for sensing its environment and locating food.
“Typically, arthropods have one or more pairs of front legs that are modified for specialized functions, such as detecting their surroundings and capturing prey,” said Luke Parry, a former Yale postdoctoral researcher now serving as an associate professor at the University of Oxford and co-corresponding author of the study. “These adapted legs enhance their adaptability, much like a biological Swiss army knife.”
Additionally, the fossils of Lomankus demonstrate that Megacheirans evolved and diversified longer than was previously estimated. This species is among the few known Megacheirans that persisted past the Cambrian Period (485 to 541 million years ago) and into the Ordovician Period (443 to 485 million years ago). Paleontologists believe that Megacheirans were largely extinct by the onset of the Ordovician Period.
The newly discovered Lomankus fossils are also linked to Yale’s paleontological work that dates back over a century.
The location of their discovery, Beecher’s Bed, was named after Charles Emerson Beecher, who led the Yale Peabody Museum from 1899 to 1904. Beecher wrote foundational papers on the anatomy and relationships of trilobites (among the earliest arthropod groups) from this site, and his work has been built upon by other scientists for many years.
Briggs is among those researchers. His initial paper regarding the fossils from Beecher’s Bed was published in 1991, and as the curator of invertebrate paleontology at the Peabody in the early 2000s (later becoming director of the museum), he oversaw Yale’s lease of the site for field studies until 2009.
Paleontologist Yu Liu from Yunnan University in China, who co-authored the study, reached out to Briggs about the new fossils from Beecher’s Bed that he obtained from a Chinese fossil collector. Briggs subsequently involved Parry, with whom he was collaborating on similar fossil research at the Peabody.
“The preservation is outstanding,” Briggs remarked. “The density of the pyrite is noticeably different from the mudstone that buried them. We utilized computed tomography [CT] scanning to extract their details, providing us with 3D images of the fossils.”
The new fossil samples have been donated to the Peabody Museum.
