The tiny remnants of an extinct, bug-like creature discovered in the 500-million-year-old British Columbia Burgess Shale Fossil Deposit add a new branch of the evolutionary tree of life, says a doctoral student who tracked the development of the organism.
The discovery of fossilized soft tissue, including the unique digestive tract, antennae and appendages of extinct Agnostides, helps solve a long-standing evolutionary puzzle about Agnostide's pedigree, says Joe Moysiuk, Doctoral in Ecology and Evolutionary Biology at the University of Toronto ,
The Peer Review study, published Wednesday in the Proceedings of the Royal Society B in the United Kingdom, links the agnostids with trilobites as distant cousins. Evolutionary researchers have considered whether trilobites were related to Agnostids, and new research proves the link, Moysiuk said.
"Agnostids seem to be the sister group we call a distant group cousin of the trilobites," he said. "They are more closely related to other trilobites than other anthropods, such as crustaceans or similar arachnids, spiders, and the like."
Trilobites, also extinct, resemble today's horseshoe crabs, Moysiuk said.
He and paleontologist Jean-Bernard Caron, associate professor of evolutionary biology at the University of Toronto and senior curator of the Royal Ontario Museum, conducted the research.
Mr. Moysiuk said that her work also helps answer questions about the origins of Agnostides, who lived from 520 million to 450 million years ago.
The work underlines the importance of further exploring Burgess Shale to follow the developmental process of other species, Mr. Moysiuk said in an interview.
"This is an animal that is a mystery, where it fits into the tree of life for a very long time, and it is always nice to put in a small puzzle piece.
Agnostids are usually less than an inch long, with armor plates on their backs, a circular head shield, and a similar-looking rear shield.