Downy feather fossils from the Lower Cretaceous of the Jiuquan Basin, Gansu Province, Northwest China

Abstract

Mesozoic feather fossils are well known for their exceptional preservation. However, the scarcity of quantities and the lack of fine structural details preserved in carbonaceous fossils, most studies have focused on the macro-morphology of such feather fossils, neglecting the significance of the microscopic morphology. A group of 28 downy feather fossils preserved in the Lower Cretaceous strata of the Jiuquan Basin are similar to the modern feather, including basic structures such as calamus, barb, and barbules, and are considered to be early downy feathers. Based on well-preserved and quantified feather characteristics, multivariate statistical analysis (PCA and CVA) was used to compare fossil groups with modern down feathers. The results revealed that the microscopic morphology of fossil feathers was noticeably different from living birds, that feathers from the Early Cretaceous may not yet be true down feathers. And the species specificity between different specimens within the fossil taxa suggests that they may have come from different coelurosaurs. This gives us further information about the evolution of Early Cretaceous feathers.