DINOSAUR FOUND WITH BIRD IN ITS GUT

At least one non-avian dinosaur, Microraptor gui, feasted on birds, according to a new paper published in the journal Proceedings of the National Academy of Sciences.

The evidence is strong. Paleontologists found a fossil of the small, bird-like dinosaur with remains of a bird in its gut. It appears that the dinosaur grabbed the bird and swallowed it whole. The bird must have been the dinosaur's last meal, given how fossils for the two animals were preserved together over millions of years.

Before I continue here, for the sake of brevity, the word "dinosaur" by itself in this text will refer to a non-avian dinosaur. Birds are living dinosaurs, confusing the whole matter. Paleontologists continue to grapple over the differences and similarities between the two animal groups. For example, there's ongoing debate on whether or not the world's supposed oldest known bird was actually a dinosaur.

This latest discovery sheds important light on how some dinosaurs and birds interacted.

The project leader was Jingmai O'Connor of the Institute of Vertebrate Paleontology and Paleoanthropology in China. O'Connor and colleagues Zhonghe Zhou and Xing Xu write in the paper, "Preserved indicators of diet are extremely rare in the fossil record; even more so is unequivocal direct evidence for predator–prey relationships. Here, we report on a unique specimen of the small nonavian theropod Microraptor gui from the Early Cretaceous Jehol biota, China, which has the remains of an adult enantiornithine bird preserved in its abdomen, most likely not scavenged, but captured and consumed by the dinosaur."

I love that enantiornithines have their own Facebook page. As you can see there, they were extinct birds that still retained teeth and had clawed fingers on their wings. These birds evolved for tree living, given how their legs and feet were shaped. The Microraptor therefore likely lived in trees too.

The tree connection is a big deal because, since these animals "were distinctintly arboreal," according to the researchers, the newly described fossil "suggests that Microraptor hunted in trees thereby supporting inferences that this taxon was also an arborealist, and provides further support for the arboreality of basal dromaeosaurids."

In other words, flight probably evolved to permit animals to live in trees. Another theory has held that animals began to fly for hunting or defensive purposes. Trees instead seem to be key.

Here's another look at the bird-eating dinosaur Microraptor gui, which lived about 125 million years ago. It's been found with traces of feathers on its wings and legs. Fossils for it suggest that the small dino was about 30 inches long and only weighed about 2 pounds.