The Dinosaur Microbiome
Recently years have seen spectacular claims published about organic material preserved in dinosaur bones, including DNA, protein, even cells and blood vessels. But even if we can avoid contamination of samples after excavation and during analysis, what about contamination in the ground? One of the most important discoveries about our biosphere is that it’s much, much larger than we thought- microbes live everywhere from the soil just under our feet to rock miles underground, a deep biosphere far beneath the Earth’s surface, and the ocean crust. If microbes can thrive deep in the rock, why not inside fossils too? In a new study, we’ve sequenced DNA and isolated organic material from inside a Centrosaurus bone. But instead of dinosaur, the DNA sequences are bacteria, and the amino acids show evidence of recent biological activity. See the writeup here.
Mass extinction of pterosaurs at the end of the Cretaceous
Pterosaurs, winged cousins of the dinosaurs, appear to gradually decline in diversity before the asteroid impact that wiped out the dinosaurs, but is this pattern driven by an absence of pterosaurs, or an absence of pterosaur fossils? The pterosaur skeleton is specialized for flight, with the skeleton being made up of thin-walled tubes filled with air inside. This made them light, but it also makes their bones delicate and unlikely to survive fossilization. New fossils from northern Morocco now show us that pterosaurs remained highly diverse up until the very end of the Cretaceous period, with multiple families- Pteranodontidae, Nyctosauridae, and Azhdarchidae- surviving. Not only that, pterosaurs appear to have staged a major radiation towards the very end, producing supergiants like Quetzalcoatlus and moving into marine ecosystems.