Scientists are delighteThe ancient skeletal marine organisms with a 'complex constitution'- pictured here for the first time - are believed to be the oldest in the world. Picture: Sargylana Yakovleva

A discovery of the fossilised remains of vertebrates believed to be more than 500 million years old may shatter existing theories of the development of skeletal creatures.

The find was made by a Russian-Chinese-British expedition led by Professor Andrey Ivantsov, of the Paleontological Institute of the Russian Academy of Sciences, from August 23 to September 13 in the Ust-Maysky district of the Sakha Republic, also known as Yakutia.

The ancient skeletal marine organisms with a 'complex constitution'- pictured here for the first time - are believed to be the oldest in the world, predating finds in China and Namibia, which had a simpler structure. Prof Ivantsov said: 'The organisms found in Yakutia have a more complex structure and push the first appearance of skeletal animals on the Earth to 20 million years earlier than previously thought.'

Detailed analysis will now take place to check the initial scientific conclusions on the age and significance of the vertebrates which were found on the banks of the Maya River, close to its confluence with the Yudoma River.

Professor Andrey Zhuravlev, of Moscow State University, told Yakutsk.ru that the site comprised 'very interesting geological sections' dating to the transition from the pre-Cambrian to Cambrian geological stages - 'the transition from the time when there were not so many creatures on the Earth to the time when there were a lot of them.'

Today Siberian is famed for its cold, but in this epoch it was tropical, and hot. 'During the late Precambrian interval, and at the beginning of the Cambrian, Yakutia and the whole of Siberia was a separate continent, which was approximately located in the equatorial area. There were shallow carbonate seas. Apparently, this geographical and climatic situation allowed these skeletal mineral organisms to appear here.'

The fossils resemble fragments of snail shells.

Professor Zhu Maoyan, of Nanjing Institute of Geology and Palaeontology, said: 'If these are indeed the oldest fossils in the world, these specimens are a treasure of a planetary scale. They are very valuable for science and will be able to change our understanding of the evolution of animals on earth.'

Professor Rachel Wood, from the University of Edinburgh in Scotland, said in comments translated from Russian said: 'First of all scientifically this is unique place, because here we can see the emergence and increase in the diversity of animal organisms.

'And what I'm particularly interested is to understand, studying the probes I took here, is the process of the accumulation of oxygen in the ocean. The oxygen content in the ocean has not always been as it is now. We need to understand when sufficient oxygen was accumulated in the ocean and how it is connected with the evolution of animals.'

Further work will take place at Moscow State University, Edinburgh University and Nanjing Institute of Palaeontology, part of the Chinese Academy of Sciences, with each institution examining separate aspects of the groundbreaking discovery. Remains of animals of the Cambrian period are preserved only in China, Canada and Russia. Preliminary results from the research are expected in around one year. (The Siberian Times)