A team of researchers has discovered a half-a-billion-year-old sea creature in Canadian museum fossils that challenges our understanding of ancient arthropods. The 506-million-year-old Mosura fentoni, named after the fictional giant moth Mothra, was found in fossils from the Burgess Shale rock formation and features unique characteristics that set it apart from other extinct species.
Mosura fentoni is a small creature, about the size of a human finger, but its discovery has shed new light on the evolution of ancient arthropods. The fossilized remains include intricate details of the species’ biology, such as its nervous system, circulatory system, and digestive tract. This is extremely rare for fossils, which usually preserve only hard tissues.
The researchers believe that Mosura fentoni’s back-end gills were a specialized system for respiration, similar to those found in horseshoe crabs, wood lice, and other living arthropods. However, the reason behind this unique adaptation is still unknown. It may have been an adaptation to low-oxygen environments or an active lifestyle that required greater oxygen consumption.
The discovery of Mosura fentoni highlights that radiodonts, a group of ancient arthropods, were more diverse than previously thought. The team found 60 fossils of the newly described species between 1990 and 2022, primarily from the Raymond Quarry in Yoho National Park in British Columbia.
“Radiodonts were the first group of arthropods to branch out in the evolutionary tree,” said Jean-Bernard Caron, co-author of the study. “The new species emphasizes that these early arthropods were already surprisingly diverse and were adapting in a comparable way to their distant modern relatives.”
The discovery was published in the journal Royal Society Open Science and provides key insight into ancestral traits for the entire group of arthropods.
Source: https://www.livescience.com/animals/extinct-species/half-a-billion-year-old-3-eyed-sea-creature-dubbed-mosura-breathed-through-big-gills-on-its-butt