Researchers from all around the world have and continue to be fascinated by the Burgess Shale. Burgess Shale is remarkable fossil that came from a unique period in time, greatening our understanding of a major evolutionary event in the history of life, the Cambrian Explosion. Throughout the Middle Cambrian period, the marine Burgess Shale formation occurred in the Canadian Rocky Mountains. The Burgess Shale plays an important role in the discovery of other soft-bodied fossils in other Cambrian localities that are directly comparable. Hence, Burgess Shale is of great importance revealing the distribution of these fossils during the Cambrian period.
Burgess Shale has a tremendously larger concentration in the Lower and Middle Cambrian, these larger concentrations seem to be mostly located in North American (Laurentia) and Chinese (South China) cratons. The concentration of Burgess Shale is significantly lower in Gondwana.
Distribution of some of the Cambrian Burgess Shale-type localities (Han, J., et al., 2008).
Recent findings in Yunnan Province in Southwest China from the Lower Cambrian, show great significance, given the geographical landscape separation between the North American (Laurentia) and Chinese cratons. This discovery along with the Burgess Shale likelihood to transpire to deep waters proposes that by deep-water, migration may have happened between at least these two cartons. In the future, there may even be more discoveries around the world of the Burgess shale.
Anomalocaris was the largest predator of the Cambrian and a key animal to understand the history of life. It is clear that Anomalocaris were very important in Cambrian marine ecosystems. Anomalocaris fossils have been found all around the world but the main localities are North America, South Australia and China.
The Canadian Rockies in British Columbia is one of the largest fossil areas. The diversity of Anomalocaridids is significantly higher than formerly thought, in the Burgess Shale formation in Canada. In the 1980s in Canada, they discovered that the different fossil elements were all parts of the one animal, Anmolocaris. The fossil of Anomalocaris was first discovered in the Ogygopsis Shale and the first fossilized mouth was found in British Columbia. The Anomalocaris was the first anomalocardid ever found.
Figure 2 – A and B
Location map of Burgess Shale localities. A : Location of Mount Stephen and Mount Field. B: Members of the Burgess Shale Formation, showing the relative locations of the localitiesThe sites marked with a star – located on Mount Stephen and marked with a circle – located on Fossil Ridge.
In South Australia, on the Kangaroo Island the first record of the anomalocaridids was found in the lower Cambrian Emu bay Shale. This record of anomalocaridids was based on frontal appendages and a putative oral cone.
While Anomalocaris fossils have been found in South China and Canada, the Australian discovery was in fact, the first place an intact eye has been found. This was due to the shale rock in which it was deposited, that once had been zero-oxygen mud. At a very slow rate, the fossil had been pushed from the sea floor and after a long period the fossil ended up on Kangaroo Island, South Australia. Around 500 million years ago when the Anomalorcaris fossil was deposited in the seafloor, Australia was part of the supercontinent of Gondwana.
Anomalocaris full body fossil (arrow) ) (Daley, A.C., 2013).
Figure 4 – Anomalocaris
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Daley, A.C., (2013). Anomalocaridids, Current Biology, Volume 23, Issue 19,Pages R860–R861.
Daley, A.C. and Budd, G.E., (2010). Palaeontology, New anomalocaridid appendages from the Burgess Shale, Canada, Volume 53, Issue 4, pages 721–738.
Daley, A.C., et al., (2013).New anatomical information on Anomalocaris from the Cambrian Emu Bay Shale of South Australia and I reassessment of its inferred predatory habits, Palaeontology, pp. 1–20.
Han, J., et al., (2008). A preliminary note on the dispersal of the Cambrian Burgess Shale-type faunas, Snowball Earth to Cambrian Explosion, Gondwana Research, Volume 14, Issues 1–2, Pages 269–276.
Petrovich, R., (2001). Mechanisms of Fossilization of the Soft-Bodied and Lightly Armored Faunas of the Burgess Shale and of Some Other Classical Localities, Department of Geosciences, University of Tulsa, 600 South College Avenue,Tulsa, Oklahoma 74104-3189, American Journal of Science, Vol. 301, Page 683–726.
Zhanga, X., et al, (2008). Snowball Earth to Cambrian, Explosion Cambrian Burgess Shale-type Lagerstätten in South China: Distribution and significance, Volume 14, Issues 1–2, Pages 255–262.