Three trilobites found at the Emu Bay Shale in Australia showing injuries suggesting possible cannibalism.Credit...Russell Bicknell
The New York Times Trilobites column has a story about cannibalism among trilobites. A new study published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology found evidence of cannibalism in 512 million year old fossils from Emu Bay on Kangaroo Island off the south Australia coast.
Cannibalism is common among the millions of modern arthropod species. A praying mantis consumes her mate after copulation, termites suck blood out of wounded peers, and mosquitoes snack on larvae. But how far back does this gruesome mode of dining go in the history of life feeding on life?
Previous studies place the earliest cannibalism about 450 million years ago in the Late Ordovician period. But a study published last month in the journal Palaeogeography, Palaeoclimatology, Palaeoecology says even older evidence of cannibalism can be found in a 514-million-year-old treasure trove of trilobites on an island off the South Australian coast, at a site called Emu Bay. There, old wounds on trilobite shells abound, and fossil excrements, likely produced by trilobites, contain yet more trilobite shells. These hint that cannibalism could be dated to the early Cambrian era — over 50 million years earlier than previously thought.
Paleontologists consider a preserved meal inside fossilized guts the best evidence that one animal consumed another. But such fossils are rare.
The site at Emu Bay, however, had optimal conditions to preserve a different kind of evidence for who ate whom: fossilized injuries and fossilized feces.
