Wulong bohaiensis
- 演化之聲
- Mar 19
- 2 min read
Updated: 2 days ago
Age
Cretaceous（Aptian）
120.3 Ma
Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Order: Saurischia
Family: Dromaeosauridae
Genus: Wulong
Species: Wulong bohaiensis
Morphological description
Wulong bohaiensis is a small dromaeosaurid, with a body length of approximately 1 meter. Its tail is exceptionally long, reaching about twice the length of the body. The known specimen represents a juvenile individual, estimated to be just over one year old, and therefore had not yet reached full size. Based on growth patterns observed in other small theropods, the holotype likely represents about two-thirds of the adult body size.
The body is fully covered in feathers. Both the forelimbs and hindlimbs bear wings composed of asymmetrical feathers, forming a four-winged configuration. At the end of the tail, elongated tail feathers extend about 12 cm and display a bifurcated structure. The limb feathers exhibit iridescence, reflecting different colors depending on viewing angle, while the remaining plumage is predominantly gray.
Etymology
Wulong: from Chinese wu ('dance') and long ('dragon'), referring to its agile and dynamic appearance
bohaiensis: referring to the Bohai region, indicating that the specimen is housed in the Dalian Natural History Museum near the Bohai Sea
Biological description
The fossil of Wulong bohaiensis was discovered in the Jehol Biota of Liaoning, China. It belongs to a group of small dromaeosaurids, many of which possessed four-winged configurations similar to Microraptor.
Wulong bohaiensis is closely related to Sinornithosaurus, though the two are separated by approximately 5 million years. Three evolutionary scenarios have been proposed: that both taxa share a recent common ancestor and diverged into separate lineages; that Wulong represents a direct descendant of Sinornithosaurus; or that Wulong should be included within the genus Sinornithosaurus. The third hypothesis has been rejected due to the temporal gap and the presence of diagnostic features that distinguish the two taxa regardless of ontogeny. The first two hypotheses remain unresolved.
Although Wulong bohaiensis possesses iridescent feathers and elongated tail plumes that appear suited for display, the known specimen is a juvenile. This suggests that such features may not have been exclusively linked to sexual selection, and could have played roles in intraspecific communication. This pattern differs from most modern birds, in which display feathers typically develop only after sexual maturity.
Functional analyses suggest that Wulong bohaiensis may have been capable of some degree of flight or aerial locomotion. However, its flight efficiency was likely lower than that of modern birds, possibly due in part to the incomplete development of flight feathers in the juvenile specimen.
（Author: Bai Leng）
References
Poust, A. W., Gao, C., Varricchio, D. J., Wu, J., Zhang, F. (2020). A new microraptorine theropod from the Jehol Biota and growth in early dromaeosaurids. The Anatomical Record. American Association for Anatomy.
Croudace, A. D., Shen, C., Lü, J., Brusatte, S. L., Vinther, J. (2023). Iridescent plumage in a juvenile dromaeosaurid theropod dinosaur. Acta Palaeontologica Polonica.
41.2, 119.4
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