A new 150-million-year-old theropod-avialan has been discovered in China. Fujianvenator prodigiosus provides new insights into early bird evolution and late terrestrial ecosystems The dinosaurs era.

Birds descended from theropod dinosaurs before the late Jurassic period, but our understanding of the earliest evolution of the class Avialae, encompassing all modern birds, Deinonychus or TroodonIt became complicated due to the limited diversity of fossils from the Jurassic Period. (A branch is a group of organisms consisting of a single common ancestor and its direct descendants, representing a branch of the “tree of life”.)

Currently, no definitive Avialan has been reported, except for the Middle-Late Jurassic Yanliao Biota (166-159 million years ago) in northeastern China and the slightly younger Solnhofen Limestones of Germany. archeopteryx. So there is a gap of about 30 million years before the earliest known Cretaceous bird records. But Jurassic birds play a key role in unraveling the evolutionary origins of the bird’s characteristic body plan. More importantly, they are key to reconciling the phylogenetic disagreement over the origin of birds.

a new discovery

A joint research team from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences in Beijing and the Fujian Geological Research Institute (FIGS) identified and analyzed a new 150-million-year-old bird theropod from Zhenghe County. . , Fujian Province.

A new species has been named Fujianvenator geniusexhibits a peculiar assemblage of morphology shared with other birds, troodontids and dromaeosaurids, and demonstrates the influence of evolutionary mosaicism on the evolution of early birds.

The morphometric area of ​​the body plan and handwriting Fujianvenator genius compared to other Mesozoic theropods. Author: Ming Wang

Fujianvenator’s unique morphology

Lead author of the study and lead author of the study from IVPP, Dr. “Our comparative analysis shows that marked changes in body plan occurred in the early bird lineage, which was mainly driven by the forelimbs, eventually leading to typical avian limb proportions,” said Ming Wang. “But Fujianvenator it is a peculiar species that has deviated from this basic trajectory and has developed a peculiar hindlimb architecture.’

The surprisingly elongated tibia and other morphologies, combined with other geological observations, show that: Fujianvenator it lived in a swampy environment and was a high-speed runner or long-legged waterfowl; represented a previously unknown ecology for early birds.

Stratigraphic records and vertebrate fossil assemblages discovered in the Late Jurassic Zhenghe fauna. Author: Ming Wang

geological context and implications

“Not including Fujianvenator “We found a large number of other vertebrates, including teleosts, testis, and choristodes,” said Limin Xu of FIGS, lead author of the study.

During the Late Jurassic-Early Cretaceous, southeast China experienced intense tectonic activity due to the subduction of the Paleo-Pacific plate, resulting in widespread magmatism and simultaneous fault basins and depressions at the location of the Fujianvenator. . This geological background is essentially the same as the Late Jurassic in northern and northeastern China, where the ancient Yanliao biota is preserved.

Co-author of the study from IVPP, Dr. “The extraordinary diversity, unique vertebrate composition and paleoenvironment strongly suggest that this region documents a terrestrial fauna that we call the Zhenghe fauna,” said Zhonghe Zhou. In situ radioisotope dating and stratigraphic studies limit the Zhenghe fauna to 150-148 Ma. For this reason, Fujianvenator It documents one of the stratigraphically youngest and geographically southernmost representatives of the Jurassic birds.

The discovery of Zhenghe fauna opens a new window into the planet’s Late Jurassic terrestrial ecosystem, and the joint IVPP and FIGS research team plans to continue exploring Zhenghe and its surroundings. Source