World's smallest dinosaur egg fossils discovered in China

This undated file photo shows a new type of dinosaur egg fossils discovered in the city of Ganzhou, east China's Jiangxi Province. (China University of Geosciences (Wuhan)/Handout via Xinhua)

NANCHANG, Oct. 17 (Xinhua) -- Chinese researchers have discovered a new type of dinosaur egg fossils in east China's Jiangxi Province, with one measuring just 29 mm in length, the smallest ever found globally.

Following a three-year study, the team comprising researchers from the Jiangxi Geological Survey and Exploration Institute (JGSEI), China University of Geosciences (Wuhan) and the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences confirmed the six egg fossils dating back to the Late Cretaceous period, over 80 million years ago, as dinosaur eggs.

The relatively complete, irregularly arranged egg fossils were found in a well-preserved nest at a construction site in Meilin Township in Ganxian District in the city of Ganzhou in 2021.

Using scanning electron microscopy and electron backscatter diffraction, the team of researchers analyzed the microstructure of the eggshells, and determined that their morphology and microstructure suggest they belong to a non-avian theropod, said Lou Fasheng, chief engineer at the JGSEI.

The most complete egg has a maximum length of only 29 mm, setting a new record for the smallest dinosaur egg fossil, Lou said. The previously known smallest dinosaur egg fossil was found in China's Zhejiang Province, measuring approximately 45.5 mm X 40.4 mm X 34.4 mm in dimensions.

This latest discovery expands the diversity of dinosaur eggs from the Late Cretaceous and offers valuable insights into the evolution of theropods during that period, according to Lou.

The findings were published online on Monday in the journal Historical Biology.

Lou said the research team will use micro-CT scanning to reconstruct the burial state of the egg fossils, study their formation process and further pinpoint the dinosaur type that laid these eggs as well as the reproductive methods of the species.

This undated file photo shows a new type of dinosaur egg fossils discovered in the city of Ganzhou, east China's Jiangxi Province. (China University of Geosciences (Wuhan)/Handout via Xinhua)