What caused the death of this ancient bird with small stones in its throat?

Fossils can often identify the type of animal that lived millions of years ago, yet they rarely show the exact circumstances of its demise. An extraordinary 120-million-year-old bird fossil at Chinas Shandong Tianyu Museum of Nature may be a unique case in this regard.

Among the thousands of bird fossils at Shandong Tianyu Museum, this one immediately caught my attention, said Jingmai OConnor, associate curator of fossil reptiles at Chicagos Field Museum. It was clear that we were looking at a previously unknown species.

Although its skeletal structure and prominent teeth resembled the larger Longipteryx bird, this newfound species was only about the size of a modern sparrow. A surprising discovery came when the fossil was examined under a microscope.

There was a strange cluster of stones in its esophagus, right next to the neck vertebrae, OConnor explained in a study published in Palaeontologica Electronica. I had never seen anything like it in other fossils.

While it is common for some animals to ingest stonesknown as gastrolithsfor digestive purposes, further investigation revealed that this was not the case for the new bird. Crocodiles, ostriches, and chickens are examples of species that swallow stones to aid in grinding food, but the cluster in this bird appeared unusual.

Using CT scans and comparisons with other birds known to use gizzard stones, the research team determined that the fossil contained over 800 small objects that were not traditional gastroliths. Many of them werent even stones, but tiny clay-like spheres, OConnor noted. They clearly werent swallowed to help digest food.

The team proposed that the bird, possibly sick, had ingested the objects and then attempted to regurgitate them. Unfortunately, the mass became lodged in its throat, likely causing its death by choking.

Based on this discovery, the bird was named Chromeornis funkyi. The genus name is a tribute to OConnors favorite musical duo, the techno-funk band Chromeo, who expressed delight at the unexpected homage.

Author: Ava Mitchell