Fukuipteryx

In 2013, the first associated skeleton of an Early Cretaceous bird from Japan was collected at the Kitadani Dinosaur Quarry in Katsuyama, Fukui, central Japan. Unlike many other Early Cretaceous bird specimens, the specimen was three-dimensionally preserved, and exhibited several autapomorphies, which lead to the creation of a new taxon.[1]

In 2019, the type species Fukuipteryx prima was named and described by Takuya Imai, Yoichi Azuma, Soichiro Kawabe, Masateru Shibata, Kazunori Miyata, Wang Min and Zhou Zhonghe. The genus name combines a reference to Fukui with a Ancient Greek pteryx, meaning "feather". The specific name means "the first" in Latin and refers to its basal position on the avialan phylogenetic tree.

The holotype, FPDM-V-9769, was found in a layer of green sandstone from the Kitadani Formation that dates from the Aptian, about 120 million years old. It consists of a partial skeleton with a lower jaw. In total, a right surangular, two cervical vertebrae, four back vertebrae, two sacral vertebrae, five tail vertebrae, the pygostyle, ribs, a wishbone, both coracoid pelvis bones, the right ilium bone, the left upper arm bone, the ulna and radius of both forearms, the second right metacarpal, the left hand and both lower hindlimbs minus the calf bones and toes are preserved. The skeleton is not articulated but is preserved three-dimensionally. It is a subadult animal, less than one year old. It is part of the collection of the Fukui Prefectural Dinosaur Museum. The fossil was not fully prepared from its matrix and the bones were reconstructed via a CAT-scan.[1]

Fukuipteryx was placed basally in the Avialae. A cladistic analysis found a position below Jeholornis in the phylogeny, as the sister group to Pygostylia. The writers saw the Avialae as more derived than Archaeopteryx. This means that Fukuipteryx is the first basal avialan found outside of China.[1]