Imagine a creature shaped like a toilet brush running on the sea floor about 500 million years ago near what is now southwestern China. Now imagine this toilet brush with floating eyes on the rods; a pair of arm-like appendages bordered by spines; and a tail fan with long, wide blades, and you’ve got a nice picture of a recently described strange animal that lived in the Cambrian period (541 to 485.4 million years ago).
In 1990, scientists found fossil specimens, one of which was almost completely juvenile, at Chengjiang Lagerstätte in Yunnan Province, China. The juvenile was nearly 6 inches (15 centimeters) long and about 2 inches (5 cm) wide, and belongs to a group of extinct oceanic ancestral arthropods called radiodonts, the researchers reported Sept. 7 in the journal. Journal of the Geological Society (opens in a new tab).
Initially, researchers identified this strange animal as a previously known species of radiodont. (The group gets its name from the circular ring of teeth surrounding the animals’ mouths.) However, the fossil’s front pair of spiny limbs — known as the predator’s appendages — differed from all other radiodonts, leading to a recent reevaluation of the fossil. , said lead study author Han Zeng, an associate professor at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences.
Although radiodonts share similar body plans, the species “are primarily distinguished by the various forms of predator-like appendages,” and those found in the fossil were so unique that the researchers determined they belonged not simply to a new species, but to an earlier unknown species. , Zeng told CNET in an email.
related: A new study has found that the “strange miracle” of evolution has an even stranger cousin
They nicknamed the strange species Innovatiocaris maotianshanensis, According to the study, the genus name comes from the Latin words for “innovation” and “crab,” and the species name refers to Maotianshan, the site in Chengjiang where the fossils were found. During its lifetime, this species was one of the most feared predators in the ocean; In fact, radiodonts are among the oldest giant apex predators on Earth, Zeng said.
(opens in a new tab)
“Their appearance in the Early Cambrian approximately 520 million years ago indicates the formation of complex food webs and marine ecosystems,” he explained. “In addition to their ecological importance, Radiodonta have a very bizarre morphology that has puzzled scientists for more than a century since their first fossil discoveries in [the] 1880s”.
Radiodonts are so oddly shaped that for decades paleontologists have identified their individual body parts as belonging to a wide range of animal groups. Some of the unusual radiodont relatives of this newly described animal had rear-facing vents and trunks with claws, etc looked like the Millennium Falcon. in the Star Wars movies or vacuumed booty like a Roomba.
It wasn’t until the 1980s, when scientists discovered the first complete radiodont fossils, that researchers finally decided to classify the group “as an ancestral lineage of arthropods,” Zeng said.
in I. maotianshanensis, “the carnivores’ spiny appendages indicate predation on relatively large prey,” while its large eyes suggest it had good vision, Zeng said. The gills and shields along its body were probably used for breathing and swimming, while the tail structures helped it turn and maneuver. “Overall, these body structures made this animal an active predator,” Zeng said.
I. maotianshanensis offers intriguing new clues about these elusive and strange arthropod ancestors. But with each new discovery of fossil radiodonts, new questions arise about the ecology of the group and evolution about their 120-million-year history, such as the number of species, how they hunted and fed on ocean prey, and how they evolved, Zeng said.
As a new genre, “Innovatiocaris suggests the presence of a new evolutionary lineage among the Radiodonta,” hinting that much remains to be discovered about the group’s diversity and evolutionary history, Zeng told CNET. “Future new Radiodonta fossils will definitely tell us more,” he said.