New Timeline for Tetrapod Biodiversity found in Fossils

A new study and timeline has been released showing 190 million years of tetrapod biodiversity, exceptional data for fossils and paleontology.

Recently, we have been able to provide some answers to the questions of how diverse through time has life been, based on the building of large fossil occurrence databases and new methods of analysing them. One such development has been the Paleobiology Database, a professional crowd-sourced archive of fossil history, where the context of fossils is provided in both space and time, and largely based on the published record of fossil discoveries.

…By applying SQS with our development of large fossil occurrence datasets, voila, we are able to gain renewed insight into the diversity of life through history in a way that accounts for the inherent biases of the fossil record!

And that’s just what a new study in PLOS Biology set out to do. Led by Roger Benson of the University of Oxford, an international team of researchers applied SQS to one of the largest tetrapod fossil occurrence databases ever assembled (if not the largest!), comprising more than 27,000 individual fossil occurrences! This represented almost 5000 fossil species, and the data were restricted to just those fossils that dwelled on land – so this excludes groups like ichthyosaurs and plesiosaurs, for example. They also excluded flying tetrapods, so birds, bats and mammals, as these are known to have very different preservational histories in the fossil record. For palaeontology though, this is definitely ‘big data’.

The team restricted their analyses to just the Mesozoic to early Paleogene, a time span of around 190 million years (a fairly long time, even by geological standards!). If you think about it, that’s 5000 species over about 190 million years, which compared to 30,000 around today is pretty weird even in itself.

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Oldest Fossils Found in Australia

Stromatolites in Sharkbay Australia - Wiki Commons

Live Science reported that a 3.5-billion-year-old fossil microbial community has been found in Australia by scientists, revealing some of the most ancient fossil life forms ever discovered.

The new find reveals that a scant 1 billion years after Earth’s origin, complex microbial communities that clung to sediments along the windswept seashore had already begun harvesting energy from sunlight, rather than the rocks.

…A few stromatolites, or domelike like rock structures built by ancient microbial communities, have been found at the Strelley Pool formation in Australia that may date to about 3.45 billion years ago. Fossil sulfur-eating microbes from about 3.4 billion years ago have also been found there as well. Other fossils from South Africa reveal microbial communities that date to 2.9 billion years ago.

…More primitive rock-eating bacteria, called chemolithotrophs, likely evolved before the microbial mats, though no trace of Earth’s earliest pioneers has yet been found. Chemolithotrophs harvest energy by chemically modifying minerals such as iron or sulfur in the rock, and many such bacteria are still alive today.

But the newly discovered communities were anchored to the seashore close to sun and water, so they probably weren’t eating minerals found in rock. Instead, they must have harvested energy through photosynthesis, suggesting such bacteria evolved earlier than previously thought.