Over 500 million years ago, Matt Groening and The Simpsons introduced us to Blinking, mutated fish with extra eyes that swam from an old fish hole in Springfield, pursuing their prey through Cambrian seas. Once you catch a quarry, a circular mouth lined with teeth will do the rest.
This creature, named Mothra Fentoni, is a remarkable addition to the peculiar fossils preserved in the Burgess Shale, a significant fossil deposit in the Canadian Rockies. However, findings published in the journal on Wednesday Royal Society Open Science suggest that Mothra may not be as alien as it initially appears.
The first Mothra specimens were unearthed over a century ago by paleontologist Charles Walcott, who discovered Burgess Shale in 1909. In recent years, paleontologists at the Ontario Museum in Toronto have unearthed “layers of seabeds revealing a plethora of Mothra fossils.”
Although they were not fish, it was evident that the masses from the sea related to Radiodonts, the group of ancestral arthropods dominating the Cambrian food chain. However, comprehensive examinations of these animals only began in 2012 when numerous Mothra specimens were found at Marble Canyon, an outcrop of Burgess Shale.
“The collection of both old and new specimens motivated us to finally understand this animal,” said Joseph Moiszk, a paleontologist who studied the Marble Canyon fossils during his doctoral research.
Dr. Moiszk collaborated with advisors at the Royal Ontario Museum, including Jan Bernard Carron, to analyze approximately 60 ocean specimens. Like other Burgess Shale creatures, many Mothra specimens are well-preserved, showcasing features such as the gastrointestinal tract and circulatory system. Some even exhibited traces of nerve bundles in each of the creature’s three eyes.
The team meticulously documented the detailed anatomy of the flat fossils by photographing Mothra specimens under polarized light.
A defining characteristic of living arthropods is their body division into specialized segments. For instance, crustaceans like crabs have varying appendages suited for different functions such as feeding and locomotion. Fossils of early arthropod ancestors, including other Radiodonts, display relatively simple body plans. Consequently, researchers have long theorized that segmentation evolved slowly over time.
Mothra supports this trend. Though measuring only 2.5 inches in length, the creature’s body was divided into as many as 26 segments.
“This feature has never been observed in this group before,” remarked Dr. Moisiuk, currently at the Manitoba Museum in Winnipeg.
Along with its broad swimming flaps, the animal had a highly segmented trunk behind its body. Researchers note that this area resembles abdominal structures used by crabs, woodlice, and various insects for respiration.
Optimizing oxygen intake was crucial for active predators like Mothra. Researchers believe the animal hunted small prey in open waters while needing to distance itself from larger contemporaries, such as the 2-foot-long, oddly-shaped titanocory.
Since no other Radiodont displayed such a specialized trunk, researchers have classified Mothra in its unique group. Instead of naming the creature after that three-eyed cartoon fish, the team drew inspiration from another pop culture icon, Mothra, Godzilla’s winged adversary. Dr. Moysiuk stated that the name pays homage to the creature’s nickname while celebrating the lasting appeal of Japanese Burgess Shale creatures.
The team also identified other notable features in Mothra, such as dark, reflective patches and swimming flaps within the animal’s body. Researchers speculate these could indicate spaces for blood vessels, possibly linked to the heart’s pumping system.
However, some scientists remain skeptical that these features represent fossilized blood vessels. Joanna Wolf, a paleontologist at Harvard University who wasn’t involved in the study, suggested they might represent other structures, such as the digestive tract.
While some of Mothra’s attributes may stir scientific debate, Dr. Caron believes the body segments of this ancient sea creature reveal ties to modern arthropods. “It certainly is a very unique animal,” he concluded.
Source: www.nytimes.com
