Oldest Animal Fossil Discovered By Scientists

A group of scientists from Australia, Russia and Germany have found that a 558 million-year-old fossil of Dickinsonia was an animal. Dickinsonia was belong to Ediacaran biota, a group of organisms which lived 571 million to 541 million years ago in Ediacaran Period. It was a marine animal and could grow up to 1.4 meters. From the previous fossil records, we thought that animals were first appeared during the Cambrian Period.  But, this new finding reveals that the animals might have started to appear before the Cambrian period; that is in the Ediacaran period. The Dickinsonia fossil was discovered in the White Sea region of Russia. It is the oldest animal fossil now.

(Dickinsonia Fossil - Wikipedia)

The scientists studied the fossil deposit of lipids from the organism. Fossilized lipids are usually used as biomarkers to identify the types of organisms. Because, different types of organisms produce different types of lipids. For example, green algae produce predominant amount of stigmasteroids, lichens produce ergosteroids and animals produce cholesteroids. The scientists have used gas chromatography - mass spectrometry to identify the fossilized lipids. 

(Reconstruction image of Dickinsonia - Wikipedia)

They have collected samples above and below the Dickinsonia fossil. This samples were examined to find whether other organisms lived around the Dickinsonia fossil. They compared the results from these samples and actual sample from the Dickinsonia fossil. The comparison helped to remove contamination from other organisms and give exact lipid content of the Dickinsonia fossil. The samples collected around the Dickinsonia fossil contained 71.3 to 76.0% of stigmasteroids and 10.6 to 11.9% of chlosteroids. It may indicate the presence of green algae. The scientists have mentioned that the presence of stigmasteroids was common in Ediacaran period organisms.

(See the below video about the scientists talking about this interesting discovery)

The gas chromatography experiment with the samples collected from the Dickinsonia fossil showed the presence of 93% cholesteroids, 1.8% ergosteroids and 5.2% stigmasteroids. This result clearly shows that the Dickinsonia might belong to animal kingdom. This discovery brought both surprise and controversy among the scientific community. As usual, more scientists will work on the Dickinsonia fossils to update this report. The common people, like us, are always curious to know more about the prehistoric animals and other organisms.