Werkgroep Fossielen regio Wageningen

American palaeontologists have discovered small fossils that may show that the assumption that the first land animals came ashore as tadpoles is incorrect. The fossils come from Mazon Creek, in the US state of Illinois. 

An almost perfectly preserved pterosaur has been found in Brazil. Its bone structure was examined using an electron microscope and appears to be similar to that of modern birds. Because it was encased in limestone, even organic molecules have been preserved – steroids!

The ammonites became extinct during the mass extinction 65 million years ago, following the asteroid impact. The nautilus, however, did not. An attempt has been made to explain this by referring to the size of the eggs they laid, but this hypothesis has been shown to be incorrect. The reason for their extinction therefore remains unknown for the time being.

A fossil from South Africa belonging to the dicynodont genus Lystrosaurus, dating from the Early Triassic, has been examined using high-resolution CT scans and synchrotron radiation. Crucially, the symphysis of the lower jaw is not fused, a developmental feature found only in the embryos of modern birds and turtles prior to hatching. The full article can be read on the Plos website. Beautiful illustrations and photos!