Spectacular fossil site discovery intrigues scientists

20 February 2014

Unknown animal species from half a billion years ago have been uncovered in the Canadian Rockies.

A team of scientists working in Canada have unearthed an extraordinary new site of exquisitely preserved animal fossils from the Cambrian Period to rival the Burgess Shale.

New species

Museum palaeontologist and zoologist Dr Xiaoya Ma said it was a significant and exciting find because of the abundance of new fossil material, some of which are completely new taxa (groups) of animals.

A team led by Royal Ontario Museum palaeontologist Dr Jean-Bernard Caron originally made the discovery in 2012. They reported their findings in the journal Nature Communications last week.

Burgess Shale rival

Prior to this newly discovered site known as Marble Canyon in Kootenay National Park in British Columbia, the most important Cambrian fossil sites have been the Burgess Shale, also in the Canadian Rockies, discovered in 1909, and the Chengjiang biota in Yunnan province, China, uncovered in 1984.

Some of the taxa found at Marble Canyon have previously only been found in the Chengjiang biota, which not only expands the geographical distribution of these animals, but also their longevity since the new site is around 15 million years younger than the site at Chengjiang.

Cambrian big bang

The Cambrian period, between 541 and 485 million years ago, saw a sudden global explosion in the number and diversity of fossil records that are similar to modern animals. Researchers continue to explore why this happened.

Most of the fossil specimens and the majority of species found at Marble Canyon are arthropods, the group of jointed-legged animals that includes lobsters, insects, millipedes and spiders.

Secret location

Although the new site is reported to be around 40km from the Burgess Shale, the exact location is being kept secret to protect it from pillaging from fossil hunters. 

Dr Ma and fellow Museum palaeontologist Dr Greg Edgecombe both work on specimens collected from the Burgess Shale and Chengjiang, some of which are kept in the Museum's collection.

In 2012, they were the first to report on fossilised neural tissue they found in some of the Cambrian arthropod fossils from the Chengjiang biota, which allowed them to compare the brain structure of these ancient animals with living arthropods.

Although most ancient fossils only contain what's left of hard exoskeletons or shells, Dr Ma said that in exceptional circumstances soft tissue, such as muscle, the gut or part of the nervous system, can be preserved.

Museum collaboration

Dr Ma and Dr Edgecombe are hoping to establish future collaborations with the team behind the Marble Canyon research because similar traces of fossilised brain are reported by the Canadian researchers. 

Dr Edgecombe said that comparing the ways in which these tissues are preserved in different fossil deposits and in different species, such as those from Marble Canyon and Chengjiang, could guide the search for more examples of early brains in the fossil record. 

More than lucky

Dr Ma, who studied zoology at Yunnan University in China before she became fascinated by fossils found at Chengjiang, said that discoveries such as Marble Canyon can appear to be luck, but that the scientists who make them always know what they're looking for.

  • by Nicola Pearson

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