Bird or dinosaur?
During the 20th century, scientists often spoke of the extinction of dinosaurs, linking it to a mass die-off at the end of the Cretaceous period caused by a colossal meteor strike over what is now Mexico. Later findings clarified that many dinosaurs persisted in other forms, and today birds are recognized as members of the dinosaur lineage, specifically theropods. Birds diverged from bipedal dinosaurs during the Jurassic, though gaps in the fossil record make details about their early evolution sparse. Researchers continue to debate how birds first learned to fly—from gliding from trees to running and taking off from the ground. To understand how reptiles evolved into the birds that dominate modern ecosystems, scientists study the oldest known avian and dinosaur species. Close relatives among living birds and dinosaurs remain housed in their own distinct evolutionary lineages.
Researchers from the Fujian Geological Research Institute and collaborators identified what appears to be one of the oldest bird-like creatures in the fossil record. Discovered near Yangyuan village in Fujian Province, the specimen dates to roughly 148–150 million years ago. The fossil preserves a detailed skeleton, including elongated legs, wings, a pelvis, a spine, and numerous ribs, enabling a highly accurate reconstruction of its form. The specimen has been given the name Fujianvenator genius.
The creature was medium-sized, comparable in body mass to a wedge-tailed pheasant. Estimates place its weight around 641 grams, with the skeleton indicating a juvenile individual. Notably, the humerus measures 1.38 times longer than the femur, a ratio typical of avian lineages that follow the Jurassic into the Cretaceous. The tibia is particularly distinctive, reaching about twice the length of the femur and among the longest seen in theropods from that era. The combination of forelimb extension, hallmarks of flight in birds, alongside robust leg development, sets Fujianvenator genius apart and highlights an anatomical blend characteristic of early birds.
Runner or swamp dweller?
Understanding how early birds diversified toward the end of the Jurassic hinges on vision and limb proportions. Fujianvenator genius shares some traits with Archeopteryx, especially in the layout of the bones in the upper limbs, yet differs in the configuration of the hind region. The Fujian specimen shows limited adaptation for powered flight and notably long legs, which suggests terrestrial life as a prominent feature. This has puzzled researchers because many early birds, including Archeopteryx, are thought to have lived in trees, with gliding between branches proposed as a stepping stone to flight.
Scientists have wrestled with why such elongated limbs would appear if flight was the primary goal. A prevailing view is that longer legs could enhance running speed by delivering longer strides. Analyses of the skeleton indicate that Fujianvenator genius could have been a capable runner, perhaps outpacing some predatory theropods famed for speed. Yet there is room for another interpretation: long legs may also reflect adaptations for life in watery or flood-prone environments. In swampy habitats, extended limbs can help birds wade, and the region around Yangyuan has yielded evidence of aquatic and semi-aquatic life in ancient times.
Thus, Fujianvenator genius might have occupied a dual niche as both an agile hunter and an early coastal or riverbank hunter, possibly even a pioneer among fishing birds. The puzzle remains because details about toe morphology, which could clarify its exact lifestyle, were not preserved in the fossil material. As new discoveries surface and reexaminations of existing specimens continue, the evolutionary story of how flight emerged and how early birds adapted to diverse environments becomes clearer, piece by piece.