A complete specimen of an ancient sea predator is shedding light on how the brains of prehistoric beasts worked. The Lyrarapax unguispinus was similar to a prawn and was about 5 inches long.
Due to the fossil being so well-preserved, scientists could actually examine the structure of its brain. Similar to the velvet worms that live in jungles today, Lyrarapax had a simple brain in front of its mouth, as well as two bundles of nerve cells that sat between its claws and its eyes. This is considered a simple structure, including simpler than the other sea creatures it fed on. This mapping of the Lyrarapax's brain gives evolutionary biologists a better understanding of this creature and its prehistoric cousins' placement in the evolutionary paths to today's wildlife.
Lyrarapax unguispinus, which is Latin for "spiny-clawed lyre-shaped predator," was a sea predator during the Cambrian period. It is a new species of Anomalocaridids, segmented ocean dwellers that had large claw-like appendanges near its mouth, used to attack prey and for eating. Some Anomalocaridids were over three feet long. Anomalocaridid translated to "Abnormal Shrimp."
The facts about the Lyrarapax and its brain were reported in the paper, "Brain structure resolves the segmental affinity of anomalocaridid appendages," found in the scientific journal, "Nature." The article was authored by Peiyun Cong, Xiaoya Ma, Xianguang Hou, Gregory D. Edgecombe and Nicholas J. Strausfeld.
The Lyrarapax fossil was found at a site in Yunnan, in the south-west area of China. Many anomalocaridid fossils have been found in China. They have also been found in other Cambrian fossil sites around the world, including in the U.S., Australia, Canada and Poland.
The Cambrian was the first geological period of the Paleozoic Era, taking place from about 541 million years ago to 485 million years ago. It is remarkable for something called the Cambrian Explosion, the relatively quick evolution of life on earth from single cell organisms living in colonies to a variety of complex creatures, many of which are recognizable ancestors to today's animal life. Life on earth was mostly found in the sea during the Cambrian, excluding a few simple microbial organisms on land.
The brain that the fossil of the Lyrarapax indicates has some features in common with velvet worms and other descendants of the arthropod family that exist today.
Photo: Espen Horn