A new genus and species of non-ornithothoracine bird has been identified from bones collected in Japan.

The ancient bird lived approximately 120 million years ago during the Aptian age of the Early Cretaceous epoch.

Dubbed Fukuipteryx prima, it was the size of a pigeon and is one of the most primitive birds ever discovered.

“Fukuipteryx prima is a non-ornithothoracine bird and is the first such record to our knowledge outside north-eastern China,” said Dr. Takuya Imai, a researcher in the Institute of Dinosaur Research at the Fukui Prefectural University and the Fukui Prefectural Dinosaur Museum, and his colleagues from Japan and China.

Except for Archaeopteryx, non-ornithothoracine birds had previously been known only from the Jehol Biota and contemporary deposits in northern Korean Peninsula.

The partial skeleton of Fukuipteryx prima was found in the Kitadani Dinosaur Quarry in the city of Katsuyama in Japan’s Fukui province in 2013.

“Unlike most other Early Cretaceous birds, the specimen is 3D preserved, and exhibits several autapomorphies, leading to erect a new taxon, Fukuipteryx prima,” the paleontologists said.

A bone analysis suggests that this individual was likely a subadult (less than one year old) nearly reaching its skeletal maturity.

The bird had a set of features comparable to that of other earliest birds including Archaeopteryx.

However, it was much more advanced than Archaeopteryx and had a long, robust, and rod-shaped pygostyle — a fused cluster of tail vertebrae to which to which tail feathers are attached.

Dr. Imai and co-authors believe that Fukuipteryx prima was capable of limited flight.

“The discovery of Fukuipteryx prima further increases the geological distribution of non-ornithothoracine birds,” they said.

“It appears that they are not restricted to a relatively cold, highland lacustrine environment in the Early Cretaceous of north-eastern China, but inhabited more temperate, lowland regions such as the one represented by the Kitadani Formation, most likely with other ornithothoracines widespread around the globe.”

The findings were published in the journal Communications Biology.

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T. Imai et al. 2019. An unusual bird (Theropoda, Avialae) from the Early Cretaceous of Japan suggests complex evolutionary history of basal birds. Commun Biol 2 (399); doi: 10.1038/s42003-019-0639-4