Proterozoic Metazoans?

Complex life pushed back in time (ABC News in Science).

The Vindyan sedimentary basins in central India have been contentious for quite some time, with claims of animal body and trace fossils going back into the Meso-Proterozoic (1.6-1.0 Gya.) That claim has been given a shot-in-the-arm by new work reported in the Proceedings of the National Academy of Sciences which describes fossils found in the Vindyan from 1.65 Gya (late Paleoproterozoic) akin to those usually found in the Cambrian and Ediacaran.

So what’s going on? Is complex life really so old? Did it experience a global setback and took a billion years to recover?

There’s merit to that idea. A current puzzle of astrobiology, that I’ve blogged on time and time again, is the Fermi Paradox – in sum, if Life is similar in age to the Galaxy then why isn’t the Galaxy full of obvious signs of Life? As in alien space-junk in our Solar System, or stars shrouded in Dyson Swarms or whatever…

But what if there’s a faulty assumption? What if Life only gets so old, then gets knocked back to microbes? Perhaps we’re now in an epoch of recently removed restrictions on Life – like frequent gamma-ray bursts – and soon, in cosmic terms, the Galaxy will be colonized. Or perhaps what we’re seeing in the fossils is a reminder that the Galaxy may still be a dangerous place.