Discoveries shed light on feathered dinosaurs
This is an exciting time in paleontology. One recent week had reports about a misidentified dinosaur and about the behavior of pterosaurs.
One of the most famous prehistoric animals is Archaeopteryx. For years known as the first bird, we now know it was a feathered dinosaur (as all birds are). Discovered in 1861, another 11 skeletons of Archaeopteryx have been found since then, all in the Eichstatt area of Germany.
For more than 100 years, no other feathered dinosaurs were found until one was reported from China in 1991. Since then, dozens of species of feathered dinosaurs have been discovered around the world.
A team of researchers recently proposed that one of the skeletons, called Archaeopteryx, is not that animal but is actually a member of a group called anchiornithids, feathered dinosaurs previously found only in China.
It is only the second bird-like dinosaur from the Jurassic Period discovered outside Asia.
Putting all the evidence together, it looks like the bird branch of the dinosaur family tree originated in eastern Asia in the middle of the Jurassic Period. By late in the period, some members (including Archaeopteryx) had reached Europe, then exploded across the rest of the globe in the subsequent Cretaceous Period.
The second exciting report that week concerned pterosaurs, the flying reptiles of the Mesozoic Era. Around 200 species are known, ranging in size from those of sparrows to Quetzalcoatlus, whose wingspan approached 40 feet and when standing, had there been any giraffes then, could have looked one in the eye.
That many species had a wide variety of feeding modes — some ate fish, others insects, and some probably preyed on baby dinosaurs or the young of other pterosaurs.
Often called “flying dinosaurs,” they weren’t dinosaurs but sprang from a branch close to the dinosaur family tree. They are colloquially known as “pterodactyls,” but that term actually refers to just one of the two main groups of pterosaur.
The first pterosaur was described in 1785, but for more than 200 years, fossils of their eggs were unknown. That is in sharp contrast to dinosaurs, eggs of which were discovered in the 1920s, and since then thousands have been found.
The first pterosaur egg wasn’t described until 2004. Subsequently, a few more were discovered, but the total remained small until a few weeks ago, when a report appeared on the astounding discovery of at least 215, and possibly as many as 300, at a site in China.
Produced by the fish-eating pterosaur Hamipterus, which had an adult wingspan of about 11 feet, the eggs were about 3 inches long with shells that were thin and leathery like some lizards, not hard like birds.
The eggs, along with thousands of bones, were found in thin layers of sand that had been transported by streams into an ancient lake, probably by storm events. In one area, eight separate layers of sandstone contained pterosaur bones, four with eggs. That indicated the animals bred in large colonies along the shore of the ancient lake, and showed that the animals returned to the same site year after year.