Molecular paleontology is the study of ancient complex biomolecules associated within deep-time fossils, which may provide important information for understanding the organisms evolution and fossilization process at the molecular level,as well as facilitating the recognition of preserved biomarkers in order to identify life on other planets [1,2].In the paper by Bailleul et al.[3], the authors report the discovery of well-preserved subcellular structures morphologically consistent with nuclei and chromosomes in histological ground sections from skull bones of an Upper Cretaceous baby dinosaur.However, as the authors have stated that morphology alone is insufficient to diagnose any cellular or subcellular structures,they conducted further histochemical (Alcian blue stain for extracellular matrix of cartilage;PI and DAPI stains for chemical markers consistent with DNA) and immunological (antibodies against avian collagen H) tests.All tests were positive, providing strong evidence suggesting in situ preservation of extracellular matrix components, and even endogenous nuclear materials.