Yuezhuornis
Genus of extinct avialan
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Yuezhuornis (lit. 'Yuezhuo bird') is an extinct genus of basal avialan known from the Late Jurassic (Kimmeridgian–Tithonian ages) Nanyuan Formation of China.The genus contains a single species, Yuezhuornis yangyuanensis, known from a partial skeleton and skull. It has significantly shorter arms than its closest relatives—being proportionally more similar to many non-avialan theropods—implying it was incapable of flight. It was a close relative of Zhengheornis, which is known from the same locality.
| Yuezhuornis | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Avialae |
| Family: | †Zhengheornithidae |
| Genus: | †Yuezhuornis Xu et al., 2026 |
| Species: | †Y. yangyuanensis |
| Binomial name | |
| †Yuezhuornis yangyuanensis Xu et al., 2026 | |
Discovery and naming
The Yuezhuornis fossil material was discovered during fieldwork in the summer of 2024, in outcrops of the Nanyuan Formation near Yangyuan Village of Zhenghe County, Fujian Province, China. The specimen is housed in the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), where it is permanently accessioned as specimen IVPP V34427. It consists of a highly compressed, partially articulated incomplete skeleton preserved on a single slab. Known material includes a poorly preserved skull, components of all regions of the vertebral column, and parts of the pectoral girdle, forelimbs, pelvis, and hindlimbs.[1]
In 2026, Liming Xu and colleagues described Yuezhuornis yangyuanensis as a new genus and species of early avialan dinosaur based on these fossil remains, establishing IVPP V34427 as the holotype specimen. The generic name, Yuezhuornis, combines a reference to the Yuezhuo, a mythological bird associated with the fenghuang (Chinese phoenix), with the Greek word ornis, meaning 'bird'. The specific name, yangyuanensis, refers to the discovery of the only known specimen in Yangyuan Village.[1]
Classification
To test the affinities and relationships of Yuezhuornis, Xu et al. (2026) included it in an updated version of the phylogenetic matrix of Wang et al. (2026).[2] Yuezhuornis was recovered as the sister taxon to the contemporary Zhengheornis, a clade Xu et al. named Zhengheornithidae. These taxa are placed within the Avialae, diverging after Anchiornithidae and Archaeopteryx, but immediately before the coeval Baminornis. These results are displayed in the cladogram below:[1]
Paleoecology
Yuezhuornis is known from the Nanyuan Formation, which dates to around 150 to 148 million years ago, around the border between the Kimmeridgian and Tithonian ages of the late Jurassic period. The outcrops of this formation have been interpreted as representing a primarily swamp-like depositional environment. Most of the vertebrate fossils from the formation represent aquatic and semiaquatic animals, including indeterminate unnamed teleost fish, turtles, and choristoderes. Some other avialan dinosaur fossils have also been discovered, including the anchiornithid Fujianvenator, the closely related Zhengheornis,[2] the more derived Baminornis,[3] and some additional indeterminate birds, including a possible ornithuromorph known from a furcula. This lagerstätte is collectively referred to as the Zhenghe Fauna.[4]