Jingmai O’Connor / Field Museum
The unlucky bird fossil, preserved with more than 800 small throat stones (visible as the gray matter to the left of the neck bones)
It was no bigger than a sparrow. For some reason, he swallowed 800 stones, and, unsurprisingly, that was the cause of his death. Why did you do it? Nobody knows. Perhaps it was sick and wanted to expel parasites from its esophagus, says Jingmai O’Connor, the “punk rock paleontologist” who examined the fossil.
A prehistoric bird that lived and died 120 million years ago has presented forensic paleontologists with a intriguing mystery doctor. Somehow, the bird managed to die with more than 800 small stones in the throat, a situation that investigators believe was the cause of his death.
But, after all, why would this little bird, like size of a sparrowswallowed so many stones?
The discovery, presented in a published in Palaeontologica Electronicaraises interesting questions about the diet, behavior and physiology of prehistoric birds, particularly given the mass of stones found in the esophagus of the recently identified Chromeornis funkyi it is something unparalleled among modern birds.
“It is quite rare for us to be able to know what caused the death of a specific individual in the fossil record”, explains the paleontologist Jingmai O’Connorresearcher at the Field Museum in Chicago, in .
“Although we don’t know Why did this bird swallow all those stones?I am quite convinced that the attempt to regurgitate that mass caused him to suffocateand that’s what killed the little animal”, adds O’Connor, known in scientific circles as the ““.
O Chromeornis stands out for several reasons that have nothing to do with his death, having immediately captured O’Connor’s attention when she came across the fossil in the Shandong Tianyu Museum, in China.
The bird was fossilized in a formation known as deposita deposit of sedimentary rock that preserves, in exceptional detail, the organisms buried there – often even including details of the soft tissues.
It was the case of Chromeornisone extraordinary fossil which retains characteristics such as the contour of the skin around the neck, wings and legs; feathers; traces of dark eye pigment; and even signs of muscles — in addition to the hardest parts of the anatomy, which fossilize more easily, such as the beak and bones.
These details allowed O’Connor and his team to determine the location of the Chromeornis in the family tree of prehistoric birds.
It was a tiny animal, weighing about 33 gramsbelonging to an extinct family called Longipterygidae – small birds, with teeth only at the tip of their long beaks. Its closest similarity is with the genus Longipteryx.
It was upon examining the animal more closely that doubts began to arise as for the enormous mass of small stones that the little bird had. “I noticed that there was a very strange mass of stones in the esophagus, right next to the neck bones”, says O’Connor.
“It’s something really unusualbecause in all the fossils I know of, no one has ever found a mass of stones inside an animal’s throat”, highlights the Field Museum paleontologist.
A careful analysis of the composition of stones revealed that its mineralogy was distinct both from the rock in which the fossil was embedded, and from each other. This excluded the hypothesis of natural deposition after the death of the birdsuggesting that, for some reason, she I would have swallowed the stones while still alive.
Some birds swallow small stones to aid digestion; these stones, called gastrolytesremain in the gizzard, where a muscular section, the so-called gastric mill helps to crush and break down the food.
In some birds, when the stones are too polished to fulfill this role, the animal regurgitates them and looks for new, rougher stones to swallow.
However, the family of birds to which the Chromeornisincluding himself, shows no signs of having a gastric millthe structure responsible for grinding stones in the gizzard of certain birds. Furthermore, the volume and total number of stones were too high for the size of a bird of this size.
“We found more than 800 small stones in this bird’s throat – much more than you would expect in other birds with gizzards. And, due to their density, some of these stones They weren’t even real stonesthey looked more like little balls of clay,” explains O’Connor.
“With these data, we can clearly state that these stones were not swallowed to help crush the food”, guarantees the paleontologist.
The other hypothesis is that Chromeornis was sick. It is known that some current andswallow stones to help expel parasites, for example, or to compensate for nutritional deficiencies.
“When birds are sick, start doing strange things” says O’Connor. “So we put forward the hypothesis that this was a sick bird that ate rocks because it was sick. He swallowed too many and tried to regurgitate them all at once. But the mass was too big and got stuck in the esophagus”, concludes O’Connor.
