55-million-year-old owl skeleton reveals early evolution

Scientists at the Senckenberg Centre for Human Evolution and Palaeoenvironment, along with colleagues from Belgium and the US, have described a new fossil owl species, Primoptynx poliotauros. The 55-million-year-old skeleton is the most complete fossil found from the early stages of owl evolution, offering the first insights into the lifestyle of these ancient birds.

The fossil originates from the Willwood Formation in North America and was discovered 30 years ago by researcher Philip Gingerich. "Fossils from the early evolution of owls are extremely rare. Typically, only isolated bones or fragments are found," stated Dr. Gerald Mayr of the Senckenberg Institute. The new find, with most of the skeleton preserved except for the skull, is exceptionally significant.

Primoptynx poliotauros was roughly the size of a modern snowy owl, but its foot structure differed significantly from present-day owls. It possessed considerably larger talons on its hind toe and second toe compared to its other toes. This type of talon morphology is characteristic of modern birds of prey, such as hawks and eagles, which use their talons to kill their prey.

Researchers hypothesize that this ancient owl killed its prey with its feet, unlike modern owls that use their beaks. "It appears that the lifestyle of these early owls differed significantly from that of their modern relatives," Mayr added. The discovery also suggests a high diversity among owls in North America during the early Eocene, ranging from the small species Eostrix gulottai to this newly described large species.

It remains unclear why owls' hunting strategies evolved over time. Scientists speculate that competition with diurnal birds of prey later in the Eocene may have been a contributing factor, potentially driving owls to develop nocturnal habits.