Abstract: A typical vertebrate assemblage has been discovered in the Cretaceous Quantou Formation in Changchun area of Jilin Province. It is represented by eight main fossil vertebrate groups, including the basal Ornithopoda, Iguanodontia, Ceratopsia, Theropoda, Sauropoda, Crocodilia, Eutheria and dinosaur eggs. The basal ornithopod Changchunsaurus parvus is the most dominant taxon, with a large number of fossil bones. Herein, we define this assemblage as “Changchunsaurus Fauna”. In order to study the diversity of this fauna, the theropod dental materials in our collections have been studied in detail. The selected measurement data from the specimens are plotted on a two-dimensional scatter diagram for analysis, and the morphological comparison and identification of the specimens are carried out in combination with the features of the teeth. The study found that there are at least four different types of theropods in the fauna, respectively allosaurs, dromaeosaurs, tyrannosaurs, and a large indeterminate theropod. Among them, dromaeosaurs are reported for the first time in the Mesozoic strata in Songliao basin. The high diversity of theropods in Changchunsaurus Fauna indicates that this assemblage should be a vertebrate community with a rich species composition.

Key words: Changchunsaurus Fauna, theropod, tooth fossil, diversity