Wednesday , October 5 2022

Burgess Shale fossils add branches to the tree of life, says the report of the Royal Society


VICTORIA: The tiny remains of an extinct creature that was discovered in the Burgess Shale fossil repository of 500 million years old, adds a new branch to the evolutionary tree of life, According to a PhD student who followed the development of the body.

The discovery of fossilized soft tissue, including single digestive tract, antennas and extinct agnostic appendages, help to solve an evolutionary riddle of the agnostic genealogical tree, says Joe Moysiuk, ecologist and evolutionary biologist Student PhD at the University of Toronto.

The expert-reviewed study, published on Wednesday at the Royal Society B Records in the United Kingdom, joins the agnostids with trilobites as distant cousins. Evolutionary researchers have reflected on whether trilobites were related to agnostids and the new research shows the connection, said Moysiuk.

"The Agnostids seem to be the ones we call the brother group, as a distant cousin of trilobites," he said. "They are more related to other trilobites than other anthropods, as they say, crustaceans, such as arachnids, spiders and such."

The trilobites, which are also extinct, are similar to horseshoe crabs today, Moysiuk said.

Moysiuk and paleontologist Jean-Bernard Caron, associate professor of evolutionary biology at the University of Toronto and curator of the Royal Ontario Museum, conducted the research.

Moysiuk said that his research also helps answer questions about the origins of agnostids, which lived between 520 million and 450 million years ago.

The work emphasizes the importance of continuing to explore Burgess Shale to track the evolutionary process of other species, Moysiuk said in an interview.

"This is an animal that has been a great mystery in that it adapts to the tree of life for a long time and, therefore, it is always good to adapt to a small piece of Puzzle".

Agnostids usually have less than one centimeter in length, with back armor plates, a circular circular shield and a similar tail-shield, he said.

Moysiuk said that finding agnostids in the Shale area of ​​Burgess is important because it is not only the hard part of the conserved creature, but also the soft tissues such as its nervous system and its digestive tracts, even sometimes containing the last meal of the animal.

"These fossils give us this incomparable vision of what life was in the Cambrian period."

He said that the discovery of the soft tissue of crustaceans was "even weaker than we would have imagined."

They found a couple of sensory antennas at the head of the body of the animals and two pairs of swimming appendages, which would have been used as rowing through water, he said .

"They have many segments and these strange sorts of luck that come from them, which we have raised with the hypothesis of having been used for breathing in these animals. So they breathed the legs, potentially."

Moysiuk said that he had been to the site of Marble Canyon in Kootenay National Park, where fossils were found, but he spent most of his time at the Royal Ontario Museum, where there is a large collection of Burgess Shale fossils.

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