Image of the Day: <em>Fukuipteryx</em> Fossil
Image of the Day: <em>Fukuipteryx</em> Fossil

Image of the Day: Fukuipteryx Fossil

This ancient bird has a modern tail bone.

Emily Makowski
Nov 15, 2019
ABOVE: Side view of Fukuipteryx prima skeleton (left) and artist’s depiction (right)

Afossil of a previously undiscovered ancient avian species holds clues to the evolution of a tail bone in birds, according to a paper published in Communications Biology yesterday (November 14). A team led by paleontologist Takuya Imai at Fukui Prefectural University found the fossil at a quarry in Katsuyama, Japan and named the species Fukuipteryx prima. The pigeon-size bird lived during the early Cretaceous period, around 120 million years ago. This is the first avian fossil from this time period to be found outside China.

The F. prima fossil shares some characteristics with Archaeopteryx, the first known bird, but it also has features in common with modern birds—such as the presence of the pygostyle, a bony plate made of fused vertebrae that supports the tail feathers. Previously, the bone was thought to be an adaptation that helped enable birds to fly long distances. But because it was found fully formed in F. prima, which, like the pygostyle-less Archaeopteryx, could probably only fly short distances, Imai and colleagues report that they think it may actually just be a byproduct of the evolution of shorter tails.

Photo of the fossil (left) and schematic drawing of bones (right)

T. Imai et al., “An unusual bird (Theropoda, Avialae) from the Early Cretaceous of Japan suggests complex evolutionary history of basal birds,” Commun Biol, doi:10.1038/s42003-019-0639-4, 2019.

Emily Makowski is an intern at The Scientist. Email her at