Paleontologists at the University of Toronto (U of T) and the Royal Ontario Museum (ROM) have discovered a new sea creature that looks like a monster had many appendages and two humongous pincers to boot.
It is 508 million years old and it bears an uncanny resemblance to a lobster. This creature has 50 legs and two claws. Also its shell resembles a tent in its form. This creature is the oldest known arthropod and it had mandibles.
Arthropods are invertebrates that include in their ranks: spiders, insects and crustaceans. Others including ants, flies, crayfish and centipedes have jaws that are called mandibles. These can grip, pulverize and chop food down into bite-size manageable bits. Up until now, it wasn’t clear when these mandibles evolved.
Now though we can say with certainty that mandibles evolved by the Late Cambrian Period. This period was extant 543 million to 490 million years ago. About 21 fossil remains of this creature were found preserved in sedimentary rock in British Columbia, Canada about half a decade ago.
This four inch long creature was labeled as Tokummia katalepsis. The creature looks weird and strange by today’s standards. It legs, which were fifty in number, looked like paddles. They helped it swim and walk in the sea. Its claws had great strength. In fact, they were the strongest ever seen in an arthropod.
The claws probably allowed the sea creature to get a firm and solid grip on soft worms and make a quick meal out of them. It had a bivalve shell and two tiny eyes at the base of antennae. Its serrated mandibles were the main feature though.
Animals with mandibles constitute a large group on earth. This group includes: millipedes, centipedes, shrimps, lobsters, barnacles and several species of insects. This creature was fully formed after the spiders and mites split off from the family tree.
“This spectacular new predator, one of the largest and best preserved soft-bodied arthropods from Marble Canyon, joins the ranks of many unusual marine creatures that lived during the Cambrian Explosion, a period of rapid evolutionary change starting about half a billion years ago when most major animal groups first emerged in the fossil record,” said co-author Jean-Bernard Caron, senior curator of invertebrate paleontology at the ROM and an associate professor in the Departments of Ecology & Evolutionary Biology and Earth Sciences at U of T.
Seen from a particular angle, this creature forms the very base of mandibulates (creatures with mandibles). Its 50 body segments were another important series of features.
They represented an attenuation to the circumstances. This creature allows us a view into the evolution of arthropods. Further observation and study of it will yield rich data regarding the environment that existed 508 million years ago.
“The pincers of Tokummia are large, yet also delicate and complex, reminding us of the shape of a can opener, with their couple of terminal teeth on one claw, and the other claw being curved towards them,” said Aria. “But we think they might have been too fragile to be handling shelly animals, and might have been better adapted to the capture of sizable soft prey items, perhaps hiding away in mud. Once torn apart by the spiny limb bases under the trunk, the mandibles would have served as a revolutionary tool to cut the flesh into small, easily digestible pieces.”
The findings are described in the paper “’Burgess Shale fossils illustrate the origin of the mandibulate body plan”. Funding for the research was provided primarily by a Natural Sciences and Engineering Research Council of Canada Discovery Grant (#341944) to Caron, and Royal Ontario Museum fieldwork grants.