First Ever Fossil Of An Owl That’s Active In Daytime Unearthed In China

An exquisitely preserved fossil skeleton of a long-extinct owl unearthed in the Tibetan Plateau reveals this species hunted by day, marking a dramatic shift in our understanding of owl evolution

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Artist’s reconstruction of the recently unearthed fossil of an extinct owl, Miosurnia diurna, perched in a tree with its last meal of a small rodent, overlooking extinct three-toed horses and rhinos with the Tibetan Plateau rising up on the horizon. (Credit: Zheng Qiuyang.)

A team of scientists based in China report they have found a remarkably well-preserved fossil skeleton of an extinct owl that lived more than six million years ago during the Late Miocene Epoch in China. They unearthed the fossil in the Linxia Basin of China’s Gansu province, at the edge of the Tibetan Plateau at an elevation of nearly 2,100 meters (7,000 feet).

The team named this new-to-science owl species Miosurnia diurna in recognition of its close living relative, the Northern Hawk Owl, Surnia ulula, a medium-sized species that is active during the day.

The fossil skeleton was very nearly complete, and included body parts that rarely fossilize like the bones of the tongue apparatus (the hyoid), along with the trachea (!), the kneecap, and even tendons (!) for wing and leg muscle attachments. Amazingly, the fossil also featured visible remnants of the owl’s last meal of a small mammal (Figure 1).

F I G U R E 1. Photographic detail of the thoracic region of Miosurnia diurna (STM 20–1) with X-ray computed tomography rendering of the unregurgitated dietary pellet materials preserved in situ. The bone residues are characterized by a honeycomb-like structure, visualized in red, with blue indicating infilling sediments. The different materials were selected and rendered in Avizo (9.2 Thermo Fisher Scientific) based on density related to the gray-scale values of the CT scan. (doi:10.1073/pnas.2119217119)

I contacted lead author, Zhiheng Li, by email and received a response to my questions that was composed by both Dr Li and the study’s second author, Thomas Stidham. Both scientists are vertebrate paleontologists and professors with the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences, where they study the evolution of birds from their dinosaurian origins up through modern birds. They frequently work together on research projects such as this one.

The most remarkable feature of this fossil is its spectacular state of preservation, which allowed Dr Li and Dr Stidham to determine that this owl was active during the day.

“We studied the fossilized eye bones called scleral ossicles that are preserved in the eye socket of the skull in this owl in order to determine that it was diurnal”, Dr Li and Dr…