Chinese scientists have identified two new dinosaur species in Lingyuan County-level City, Liaoning Province, shedding light on the evolution of small, feathered theropods and the remarkable diversity of the 125-million-year-old Jehol Biota.

The research, published in the National Science Review, details the discovery of Sinosauropteryx lingyuanensis, a new species, and Huadanosaurus sinensis, a new genus and species.

A key finding of the study reveals the first direct evidence of dinosaur-mammal predation in this ancient ecosystem. The fossil of Huadanosaurus sinensis contained the remains of two mammals: a complete skeleton of a eutriconodont and fragments of a eutherian.

The study also revises the classification of these feathered dinosaurs, reinstating Sinosauropterygidae as a distinct group. Previously, they were grouped under Compsognathidae, a classification now deemed inaccurate.

The researchers connect the diversification of these dinosaurs to tectonic shifts that occurred 125 million years ago. The destruction of the North China Craton created isolated rift basins, intensifying competition among species.