After the Mother of All Extinctions, an Unexpected Triassic Fauna – #365papers – 2017 – 51

#365papers for February 20, 2017

Brayard, Krumenacker, Botting, Jenks, Bylund, Fara, Vennin, Olivier, Goudemand, Saucede, Charbonnier, Romano, Doguzhaeva, Thuy, Hautmann, Stephen, Thomazo, and Escarguel, 2017, Unexpected early Triassic marine ecosystem and the rise of the modern evolutionary fauna: Science Advances, v. 3, e1602159.

What’s it about?

This paper describes the fossils from four of early Triassic localities that have been correlated to be the same age. It is mostly descriptive of the fossils found.

Why does it matter?

The Triassic began with the the biggest extinction in Earth’s history – the Permo-Triassic extinction – which took out 95% of marine life. This group of fossils represents what was living a mere 1.3 million years later. One would have predicted that there wouldn’t be a great diversity as the Earth was still recovering from the extinction, but instead, the fauna, now called the Paris Biota, was a lively and complex assemblage of organisms showing many affinities with more modern marine assemblages.

Most notable were the presence of sponges previously known only from the Cambrian through Ordovician (200 million years earlier) and some squid-related molluscs that are only in the fossil record 50 million years later. These attest to the incompleteness of the fossil record.

Why did I read this?

I was casually looking for a good paper to use for the Wednesday Exercise in my course this week. I mindlessly did a search with the keywords Macroevolution, Fossil, and Record. This was one of the many hits. It caught my eye because of the phrase “Modern evolutionary fauna” which is a topic we’ll be covering in a few weeks.