On 7th June 2013 Science (journal) said that Pascal Godefroit, the paleontologist who led the team that described "Aurornis", is uncertain if the fossil material came from Liaoning province's 160-million-year-old Tiaojishan Formation as claimed by the fossil dealer. It may be from the province's 125-million-year-old Yixian Formation, which is known to have produced several ancient bird fossils. The failure to secure rigorous provenance casts doubt on the claim that "Aurornis" is 160 million years old and predates "Archaeopteryx". Godefroit's team will try to confirm the specimen's age by mineralogical and botanical analysis on the shale slab. 