Jaws found in 500-million-year-old fossils. A new study by scientists at the Royal Ontario Museum (ROM) has concluded that O. alata was likely one of the first arthropods with lower jaws, a departure from previous research that suggested the animal may have been a filter feeder.
The authors suggest that this biological feature likely started an evolutionary arms race, as the mandibles allowed O. alata to destroy large structures and gain access to more food sources.
Despite its odd appearance, the Cambrian creature Odaraia alata is an arthropod. Although its protective body did not survive the Cambrian, its jaw-and-mouth structure certainly did, as about 70 percent of all animals today, from insects to crustaceans, use similar methods to ingest food.
But Odaraia alata’s place as one of the earliest creatures with mandibles is actually a new discovery by scientists at the Royal Ontario Museum (ROM). While analyzing intact fossil specimens from the Burgess Shale, one of the most diverse and well-preserved fossil beds in the world, located in British Columbia, Canada, the scientists noticed jagged edges around the ancient arthropod’s mouth — a distinctive feature of mandibles. The findings were published in the journal Proceedings of the Royal Society B.
“Odarai’s head shield covers almost half of its body, including its legs, as if it were enclosed in a tube,” Alejandro Izquierdo-Lopez, lead author of the study and a University of Toronto undergraduate, said in a press release. He continued:
“Previous researchers have suggested that this shape would have allowed Odaraia to collect its prey, but the mechanism has eluded us until now. Odaraia was beautifully described in the 1980s, but given the limited fossil record at the time and its bizarre shape, two important questions remained unanswered: Was it really a lower jaw? And what did it eat?”
With 30 legs and a length of about 8 inches—a relatively large size for an animal of that particular geological period, which likely allowed it to roam in more open seas—O. alata and its chewing method have remained a mystery, largely because fossils have failed to detail these small, complex mouth parts. This has led some scientists to speculate that perhaps O. alata was a filter feeder, with its shell helping with water flow, but the results have been inconclusive.
Of the 150 samples used in this new study, 24 came from the Burgess Shale, The New York Times reports. The Burgess Shale is known in particular for its high-quality preservation of soft body parts due to various sedimentary advantages that limited the flow of oxidizer during the early burial of these animals. Because of this favorable sedimentary environment, Izquierdo-Lopez and his team were able to see details hidden from previous attempts to describe the 500-million-year-old creature.
“The Burgess Shale was a treasure trove of paleontological information,” ROM curator and study co-author Jean-Bernard Caron said in a press release. “We already know a significant amount about the early evolution of mandibles. However, some other species remained quite enigmatic, like Odaraia.”
Ancient predatory worms have forced scientists to rethink the history of life on Earth. 500 million years ago, the world was very different. In fact, all life lived in water, which was home to many animals that looked very different from those we know today.
Fossils of Selkirkia tsering found in a collection from the Fezuata Formation in Morocco. Javier Ortega Hernandez/Harvard Museum of Comparative Zoology
One of them was a group of predatory worms with throats covered in spines, hooks, and teeth to catch their prey. They built tubes around themselves and lived inside them, waiting for their next victim to crawl past. “These worms are pretty small… But if you’re an invertebrate crawling on the seafloor, this thing is a nightmare — like predatory organs coming out of its throat at you,” says Karma Nanglu, a research associate at Harvard University’s Museum of Comparative Zoology.
“The animals that came out of the Cambrian explosion… were kind of the first thing in life, like the Big Bang in a sense,” Nanglu says. “And then they didn’t last very long.”
The size of Selkirkia tsering. Javier Ortega Hernandez/Harvard Museum of Comparative Zoology
But a recent paper in the journal Biology Letters by Nanglu and paleobiologist Javier Ortega-Hernandez showed examples of a new species of this worm, Selkirkia, in the fossil record 25 million years after researchers thought they had disappeared from the face of Earth. Nanglu says the discovery could change how scientists understand life at different points in Earth’s ancient history.
“From a biological perspective, maybe some of these boundaries are a little bit blurrier than we previously thought,” he says.
Animal species shaped like a football discovered in 500-million-year-old shale. Paleontologists in Canada have discovered a new species of 1 1/2-foot-long marine animal shaped like a football, with a large protective shell on its head, a toothy mouth and a pair of sharp claws.
The new species, called Titanokorys gainesi, is thought to be part of a long-extinct group of animals from the Cambrian period, which lived about 500 million years ago. Titanokorys was a giant at a time when most sea creatures were the size of a pinky finger or smaller, according to scientists at the Royal Ontario Museum, who discovered the species in a fossil in Kootenay National Park in the Canadian Rockies.
A reconstruction of Titanokorys gainesi, a new species of extinct marine animal discovered in Canada. Lars Fields/Royal Ontario Museum
“The size of this animal is simply staggering, one of the largest Cambrian animals ever found,” Jean-Bernard Caron, the Richard M. Ivy curator of invertebrate paleontology, said in a statement.
Titanocoris belongs to a subgroup of primitive arthropods called hurdiids, which have a long head and a three-part carapace – a kind of hard outer shell.
High in the mountains of Kootenay National Park, a Royal Ontario Museum field crew removes a slab of shale containing a Titanokorys gainesi fossil. Jean-Bernard Caron/Royal Ontario Museum
“The head is so long relative to the body that these animals are really nothing more than floating heads,” said Joe Moysiuk, a University of Toronto graduate student who co-authored the study on the new species.
Scientists say Titanocorys’ broad, flat head suggests it swam close to the sea floor, using its forelimbs to pull prey toward its mouth.
A similar species discovered in the same area in 2018 was named Cambroraster falcatus because scientists thought its head shell resembled the Millennium Falcon, the ship from the Star Wars film.