Photo: Screenshot of a video posted by The Paper

The smallest dinosaur footprints ever discovered in China in Zigong city, Southwest China's Sichuan Province, possibly reveal a developmental stage of precocity or ultra-precocity for theropod dinosaurs. 

With three obvious toes, one of the tiny dinosaur footprints, measured only 10.2 millimeters long and 9.6 millimeters wide, is the smallest dinosaur footprint recorded in China. Palaeontologists believe that the footprint, along with over 40 footprints discovered on the same rock plate, belong to the footprint category of Grallator prints, which usually measure less than 15 centimeters. 

Similar to most tiny footprints of theropod dinosaurs, whether the smallest footprint came from a newborn or an adult dinosaur is still unknown. But paleontologists think that the tiny footprint came from a newborn dinosaur. The body length of the dinosaur is estimated to be about 12 centimeters, roughly the size of a modern sparrow. 

The rock plate preserves a series of relatively unified footprints of varying sizes, which researchers suggest could represent a collection of footprints from small theropod dinosaurs at different stages of development