Around half a million years ago, a skilled predator flapped its wings around the primordial ocean, drawing in its long butt gills and capturing its prey.
Recently, scientists unearthed this creature from 506 million years ago. Mothra Fentoni, discovered in fossil deposits at a Canadian museum, suggests that these early arthropods were more diverse than previously believed. The name was inspired by Mothra, a fictional giant from Japanese cinema, as this imaginative arthropod resembled moss, reminiscent of distant creatures.
Mothra may be large enough to battle Godzilla in films, but the real M. Fentoni was merely the size of a human finger. Despite its diminutive stature, this tiny organism marks a significant and rare discovery for researchers.
Fossils of M. Fentoni, primarily sourced from the Burgess Shale Rocky Formation in the Canadian Rockies, are exceptionally well preserved, revealing intricate biological details, including the creature’s nervous system, circulation system, and gastrointestinal tract. This level of soft tissue preservation is rare and offers valuable insights into the evolution of ancient arthropods.
“Very few fossil sites around the world offer such depth of understanding regarding soft internal anatomy,” said research co-author Jean Bernard Carron, Richard M. Ivy Curator of Invertebrate Paleontology at the Royal Ontario Museum, in a statement. “We can observe traces that indicate bundles of eyes possibly used for image processing, akin to living arthropods. The details are astonishing.”
Researchers published their findings on Wednesday (May 14th) in Royal Society Open Science.
Related: Scientists discover “windowed, legless, headless” creatures that roamed long before the dinosaurs
Arthropods are a vast category of invertebrates characterized by rigid exoskeletons, segmented bodies, and articulated legs. Today, they comprise roughly three-quarters of all living animals, encompassing insects, spiders, and crustaceans. One contributing factor to their evolutionary triumph is their specialized body segments. These varying segments enable arthropods to adapt, resulting in forms ranging from the familiar horseshoe crab to moths.
M. Fentoni belongs to the ancestral group of arthropods known as Radiodonts, identifiable by traits like side flaps and head appendages. These invertebrates thrived during the Cambrian period (541 million to 485 million years ago), though fossil evidence has so far depicted primarily uniform body segments.
The team collected fossils of this newly described species between 1990 and 2022 from the Raymond Quarry, mainly located in Yoho National Park in British Columbia. Many of these specimens were housed at the Royal Ontario Museum for years prior to the authors of the new study examining them closely. The researchers also discovered additional specimens at the Smithsonian National Museum of Natural History in Washington, DC.
“The museum’s collection is both old and a treasure trove of information about our past,” noted Joe Moysiuk, curator of paleontology and geology at the Manitoba Museum, in a statement. “If you think there’s nothing left to discover, just take a look inside the museum drawers.”
Researchers utilized photography and scanning techniques to create biological images of the ancient creature. They found that, unlike other radiodonts, M. Fentoni possessed multiple body segments along with gills. This species, although small, had the longest gills relative to its body size among all known radiodonts based on their findings.
The team concluded that the gills likely served as a specialized breathing system. Living arthropods such as horseshoe crabs and woodlice have since evolved similar systems. Researchers remain uncertain about why M. Fentoni required such elongated gills, but speculate it could be an adaptation to a low-oxygen environment or a possibly active reproductive lifestyle. Regardless, this discovery emphasizes the diversity of radiodonts, which was greater than previously understood.
“Radiodonts represent the earliest divergence in the evolutionary tree of arthropods, offering crucial insights into the shared characteristics of the entire group,” Caron stated. “The new species demonstrates that these early arthropods were already remarkably diverse and adapted in ways similar to their modern relatives.”
Source: www.livescience.com