[ad_1]
Paleontologists have uncovered fossils of a giant trilobite species that inhabited Australian waters about 500 million years ago (Cambrian period).
An artist impression of Redlichia Rex on the Cambrian background. Image credit: Katrina Kenny.
Trilobites are a group of extinct marine arthropods that resemble modern northern crabs and are related to modern crustaceans and insects.
These creatures appeared in the ancient oceans at the beginning of the Cambrian, about 540 million years ago, and disappeared during the massive extinction at the end of the Permian, there are about 252 million of them. 39; years.
They were extremely diverse, with about 20,000 species and their fossil exoskeletons can be found all over the world.
Double Redlichia Rex, the newly discovered species is the largest Cambrian trilobite discovered in Australia.
It was about 30 cm long, almost twice the size of other Australian trilobites of the same age.
"We decided to name this new species of trilobite Redlichia Rex – similar to Tyrannosaurus rex – Because of its giant size, as well as its tremendous paws with thorns used to crush and shred food, which could have been other trilobites, "said James Holmes, a PhD student at the University of Toronto. University of Adelaide.
A specimen of Redlichia Rex Shale of Emu Bay, Kangaroo Island, Australia. Scale bar – 10 mm. Image credit: Holmes et al, doi: 10.1080 / 14772019.2019.1605411.
The preservation of 'soft parts' – such as antennae and legs – in fossilized trilobites is extremely rare.
Redlichia Rex was discovered in the Emu Bay Shale on Kangaroo Island, South Australia, a world-renowned deposit known for this type of preservation.
"Interestingly, trilobite specimens from Emu Bay Shale – including Redlichia Rex – present wounds caused by predators that crush their shells, "said Dr. Diego García-Bellido, a researcher at the University of Adelaide and at the South Australian Museum.
"There are also large specimens of fossilized coprolites containing trilobite fragments in this fossil deposit."
"The large size of the wounded Redlichia Rex specimens and associated coprolites suggest that much larger predators were targeting Redlichia Rex, such as Anomalocaris, an even larger creature resembling a shrimp, or that the new species had cannibalistic tendencies. "
One of the main factors in the Cambrian explosion was probably an evolving "arms race" between predators and prey, each developing more effective defense and attack measures.
"The crushing size and legs of Redlichia Rex are probably a consequence of the arms race that took place at that time. This giant trilobite was probably the terror of small creatures on the bottom of the Cambrian Sea, "said Holmes.
The discovery is featured in an article published online this week in the newspaper Journal of Systematic Palaeontology.
_____
James D. Holmes et al. Trilobite Redlichia Konservat-Lagerstätte schist from southern Australia in lower Cambrian Emu Bay: systematic, ontogeny and soft-tissue anatomy. Journal of Systematic Palaeontology, published online June 12, 2019; doi: 10.1080 / 14772019.2019.1605411
[ad_2]
Source link