Scientists discover unknown lifeform they are unable to explain

The Earth is so old we may never learn exactly what lived on it and when. Especially if these creatures are teeny tiny microbes. One unknown microbe, that bizarrely feasted on desert limestone, is baffling researchers as they are unsure if this mysterious form of life still exists or went extinct eons ago. But one thing they do know is that they don’t know what it is (Picture: Cees Passchier/ Geomicrobiology Journal)

Researchers in the scorching deserts of Namibia, Oman, and Saudi Arabia uncovered a strange feature in the rocks that looked like thin, orderly tubes running through marble and limestone. But these structures don’t resemble any  known geological process which is why researchers believe they may be the work of an unidentified form of microbial life (Picture: Cees Passchier/ Geomicrobiology Journal)

Geologist Professor Cees Passchier from Johannes Gutenberg University Mainz found the structures as erosion had exposed the fossil burrows so his team looked further and found biological material inside. He said: ‘We were surprised because these tubes are clearly not the result of a geological process. We don’t currently know whether this is a life form that has become extinct or is still alive somewhere’ (Picture: Cees Passchier/ Geomicrobiology Journal)

In their paper, which is published in the Geomicrobiology Journal, the team wrote: ‘A biotic origin of the observed structures supposes the presence of liquid water, without which biological growth would be impossible. The investigated areas are currently arid, but experience occasional rain showers and regular dense coastal fog, while wet periods occurred in the past’ (Picture: Cees Passchier/ Geomicrobiology Journal)

But what kind of microbe could it be? Bacteria, fungi and lichens have shown that they can survive extreme conditions, and we know that some are endolithic – which means they can live inside rocks. So, Professor Passchier wanted to see if the organisms that created the burrows could possibly belong to any of these groups (Picture: Cees Passchier/ Geomicrobiology Journal)

The team ruled out cyanobacteria which need sunlight for photosynthesis. Fungi secrete digestive agents that were not found in the rocks. And they said that the burrows were parallel and evenly spaced which is unusual for fungi, so it’s likely it's not fungi either. The burrows were too wide to be made by one organism at a time, and there was growth rings, so it was more likely that they were formed by colonies of microbes (Picture: Cees Passchier/ Geomicrobiology Journal)

The chemical composition of the rocks meant that whatever had been there had to have been alive. Dr Passchier said: ‘As no known chemical or physical weathering mechanism can explain this phenomenon with the microstructural and geochemical observations presented here, and the micro-burrows form inside the host rock. We suggest that they are of biological origin’  (Picture: Cees Passchier/ Geomicrobiology Journal)