New fossils from Morocco show that trilobites are neatly arranged. Jean Vannier, the head of the study, said: "It may have been buried in the Ordovician ocean when they trudged from one place to another. They were buried by an ancient game of' following the leader'."
"I think people think that collective behavior is a new thing in the process of evolution, but in fact complex behavior began very early." Paleontologist at the University of Lyon, France.
A large number of marine fossils have been discovered in Morocco
Trilobites are blind, so they may keep in touch with their spiny body protrusions when marching in line. Clover chop
Vannier from Marrakech, Morocco, and his colleagues found trilobites in an area famous for well-preserved early Ordovician animal fossils in southern Morocco. This geological period began about 485 million years ago and is one of the six periods that constitute the Paleozoic. The Ordovician is famous for its diverse marine life, from primitive fish to corals to human-sized sea scorpions. Trilobites-arthropods that look a bit like cockroaches-also wandered around the bottom of the Ordovician or swam across the ocean. These elastic creatures first evolved in the Cambrian before the Otivik period and survived two mass extinctions (one at the end of Ordovician about 444 million years ago and the other at the end of Devonian about 360 million years ago). Trilobites did not disappear until 252 million years ago, when a mass extinction at the end of Permian wiped out 95% of the species on the earth.
Little is known about the behavior of trilobites, but some fossil evidence shows that trilobites can't swim or dig holes alone. Paleontologists have discovered swarms of trilobite fossils. Obviously, they gather in groups to molt or mate.
Related photo albums: CAMBRIAN creatures: primitive marine life
The new fossils in Morocco are striking because trilobites are arranged neatly and obviously will not float in place after death. Fannier said: These animals all face in the same direction and often touch each other with their spines. Vannier told Life Science that their single row layout is reminiscent of the migration of modern spiny lobsters. These Caribbean creatures lined up in the storm to go to calm waters, and their tentacles moved close to each other.
These trilobite queues reveal the collective behavior of early animals. Vannier and his colleagues reported in today's Science Report (10, 17), which reminds people of the mass migration of modern Caribbean spiny lobster (Jean Vannier). The rocks around the collective "Kdsp" show signs of repeated and rapid storm deposition. Rows of trilobites are likely to be immediately buried by avalanche-like sediments, possibly accompanied by agitated anoxic water, which helps animals suffocate quickly. These fossils record no signs of death struggle; Whatever took their lives didn't even disturb the carefully lined trilobites. Similar trilobites have found fossils in younger rocks. Vannier said that fossils from southern France showed that the same species (Ampex Prius) were arranged together. Trilobites are blind, so they may follow each other with protruding spines when they move.
"This seems to be the normal behavior of this species in different parts of the world," Vannier said.
Trilobites are not the only ancient animals that showed collective behavior. Fossils of shrimp-like synovial animals were found in China 520 million years ago. Scientists suspect that they migrated as a whole. Horseshoe crabs, which first appeared on the scene 450 million years ago, still gather on the coastline today and breed under the cover of darkness.
These strange pictures of sea monsters once ruled the ocean: 508 million years ago, furry worms looked like brushes in the kitchen. Photos of ancient worms with spiny arms were first published in Life Science.
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