'The world's oldest cannibalistic trace' can be found in fossil trilobites over 500 million years ago



Cannibalism , in which animals eat the same kind of solids, is seen in multiple animals such as mantis, spiders, and sharks, and human cannibalism , which eats human meat, has been practiced in various cultural backgrounds. Regarding such cannibalism, research results have been announced that 'the world's oldest trace of cannibalism' was found in fossil trilobites more than 500 million years ago.

Cambrian carnage: Trilobite predator-prey interactions in the Emu Bay Shale of South Australia --ScienceDirect
https://www.sciencedirect.com/science/article/abs/pii/S0031018222000475

Trilobite Fossils Suggest Cannibalism Is Older Than Once Thought --The New York Times
https://www.nytimes.com/2022/03/25/science/cannibal-trilobites.html

World's oldest known case of cannibalism revealed in trilobite fossils | Live Science
https://www.livescience.com/oldest-cannibalism-found-in-trilobite-fossils

Trilobites are marine arthropods that appeared about 541 million years ago and have had a hard exoskeleton that is easier to fossilize than soft tissues, and fossils have been found in various parts of the world. increase. Russell Bicknell , a paleontologist at the University of New England, Australia, has spent five years studying fossil trilobites about 514 million years old found in the Emu Bay Shale Formation on Kangaroo Island , South Australia. I've been doing it.

The fossil trilobites found in the Emu Bay Shale Formation are said to have two species of trilobites in the genus Redlichia , one is the relatively small species Redlichia takooensis (R. takooensis) and the other. One is a large species called Redlichia rex (R. rex) . R. rex's dung fossil contains a shell that seems to belong to a trilobite, and since many bites have been confirmed on the body of R. takooensis, R. rex called R. takooensis. It is suggested that it was preying. However, it is said that not only the fossil of R. takooensis but also the body of R. rex was found to have a bite on the body.

Bicknell has posted an image of a 'bitten wounded trilobite fossil' found in the Emu Bay Shale Formation on his Twitter account. Although these wounds are called bites for convenience, they are actually thought to be wounds made on the two legs used during predation.



'There are few other biomechanically optimized toolkits in this formation other than R. rex that can easily chew hard objects,' Bicknell said. , R. rex's body bite claims to have been caused by another R. rex attempting cannibalism.

Most of the bites found in the fossils found in the Emu Bay Shale Formation are said to have been in the abdomen rather than the head. Mr. Bicknell believes that the reason for this is that the trilobites that were about to be predated tried to escape, but 'the trilobites that were attacked on the head were eaten and the abdomen was attacked, but fossils. It suggests that there may be a survival bias that 'only remains.'

The trilobite fossils reported by Bicknell et al. Show 'the oldest traces of cannibalism in the world,' but Bicknell said that cannibalism was more common than the fossils suggest. thinking about. 'It's safe to say that arthropods have been eating arthropods since the earliest days when they became arthropods,' said Bicknell.

Allison Daley, a paleontologist at the University of Lausanne who is not directly involved in the study, admits that the bite of R. rex is certainly the result of cannibalism by individuals of the same species. On the other hand, he argued that if there was a softer prey, he would have given priority to eating it, and said that the trilobites did not have a pure cannibalistic habit.

in Science,   Creature, Posted by log1h_ik