FUKUI -- An almost complete bird fossil that was unearthed in the central Japan city of Katsuyama, Fukui Prefecture, has been confirmed as a new species, researchers announced on Nov. 14.
According to Fukui Prefectural University's Institute of Dinosaur Research and other sources, the fossil was excavated in August 2013 from stratum believed to date back 120 million years, during the early Cretaceous period.
The new species has been named "Fukuipteryx prima," after Fukui Prefecture and the Latin terms pteryx, meaning wing, and prima, meaning primitive. It is the oldest bird fossil discovered in Japan. Archaeopteryx, which lived in the late Jurassic period around 150 million years ago, uncovered in Germany, is still regarded as the oldest bird in the world.
Experts say the discovery, published in the British scientific journal "Communications Biology," provides a valuable hint about the evolution of birds.
The fossil, consisting of at least 100 bones including extremity and rib bones, was preserved three-dimensionally in a rock. Using computed tomography and other methods, a research team led by Fukui Prefectural University discovered traits that were absent in other bird fossils, including a protrusion on the pygostyle near the root of the tail feathers. Such traits were decisive factors in confirming the new species.
Analysis of bone tissue found that the fossilized bird was a young animal under the age of 1 with a wing span of about 50 centimeters. Researchers assume Fukuipteryx prima did not fly as well as modern birds, and possibly flapped its wings on the ground like chickens or just glided.
Lead author Takuya Imai, assistant professor of paleontology at the Institute of Dinosaur Research, stated, "Over 90% of bird fossils from the early Cretaceous period are excavated in northeastern China, and there's great significance in it being found elsewhere from the perspective of knowing more about the evolution of birds and their biology."
He added, "While it (Fukuipteryx prima) has a unique pygostyle, it's also very interesting that it has traits common in dinosaurs, such as having three digits."
Fukui Prefectural Dinosaur Museum in the city of Katsuyama began displaying the fossil on Nov. 15.
(Japanese original by Haruyuki Omori, Fukui Bureau)