Owl Discovered That Hunted Like A Hawk 55 Million Years Ago



Comparison of the skeleton of Primoptynx poliotauros next to that of the extant snowy owl (Bubo scandiacus) (c) Sven Tränkner & Gerald Mayr
Owl Discovered That Hunted Like A Hawk 55 Million Years Ago
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Siska Van Parys

Paleontologists have described a large owl that killed medium-sized mammals with its feet and claws some 55 million years ago. “Today, owls kill with their beak," says paleontologist Thierry Smith (RBINS), who participated to the study of the well-preserved skeleton from Wyoming, USA. Primoptynx poliotauros is a new species and a new genus.

The skeleton excavated by American paleontologists at Bighorn Basin in Wyoming thirty years ago, is one of the most complete fossilized owls of the Paleogene, the geological period after the extinction of the non-avian dinosaurs 66 million years ago. The fossil, of which all major postcranial bones have been preserved, is 54.5 to 55 million years old (early Eocene).

Different Toes

Primoptynx poliotauros was about 50 centimeters in size - comparable to Hedwig, the snowy owl of Harry Potter - and belongs to an extinct group of owls. “Its feet are different from those of today's owls”, says paleontologist Thierry Smith of the Royal Belgian Institute of Natural Sciences (RBINS), co-author of the study with Gerald Mayr of the Senckenberg Research Institute in Frankfurt and Philip Gingerich of the University of Michigan. “Owls today have four toes with claws of equal size to catch relatively small preys and kill them with the beak. Primoptynx has longer first and second toes, as seen in hawks and other members of the family Accipitridae. Those more developed toes are used to pin down prey, which are punctured by the talons. So it was an owl that hunted like a hawk on medium-sized mammals.”

This fossil shows - together with other finds - that during the early Eocene there were already many species of owls, of different sizes, which occupied different ecological niches. The success of the owls runs parallel to that of the mammals, which became very diverse after the fifth mass extinction, that wiped out the dinosaurs. The later extinction of Primoptynx poliotauros and other proto-owls may have been due to the emergence of diurnal birds of prey in the Late Eocene.

The study is published in the Journal of Vertebrate Paleontology.

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