 |
in Zheng, Bailleul, ... et Zhou, 2021. |
Abstract
Previous findings on dinosaur cartilage material from the Late Cretaceous of Montana suggested that cartilage is a vertebrate tissue with unique characteristics that favor nuclear preservation. Here, we analyze additional dinosaur cartilage in Caudipteryx (STM4-3) from the Early Cretaceous Jehol biota of Northeast China. The cartilage fragment is highly diagenetically altered when observed in ground-sections but shows exquisite preservation after demineralization. It reveals transparent, alumino-silicified chondrocytes and brown, ironized chondrocytes. The histochemical stain Hematoxylin and Eosin (that stains the nucleus and cytoplasm in extant cells) was applied to both the demineralized cartilage of Caudipteryx and that of a chicken. The two specimens reacted identically, and one dinosaur chondrocyte revealed a nucleus with fossilized threads of chromatin. This is the second example of fossilized chromatin threads in a vertebrate material. These data show that some of the original nuclear biochemistry is preserved in this dinosaur cartilage material and further support the hypothesis that cartilage is very prone to nuclear fossilization and a perfect candidate to further understand DNA preservation in deep time.
 |
| Photograph and line drawing of Caudipteryx STM4-3. a Photograph of the full slab. b Close-up on the right femur showing the extracted fragment outlined in yellow. c Line drawing of the specimen showing bones in light gray, the mass of gastroliths inside the body in pale gray and integument imprints in dark gray. cav, caudal vertebrae; cev, cervical vertebrae; Demin. P-S, demineralization and paraffin sections; fi, fibula; G-S SEM, Ground-sections and scanning electron microscopy; il, ilium; is, ischium; l co, left coracoid; l de, left dentary; l fe, left femur; l hu, left humerus; l ra, left radius; l tb, left tibiotarsus; l ul, left ulna; ma, maxilla; mtII, metatarsal II; mtIV, metatarsal IV; pu, pubis; r co, right coracoid; r de, right dentary; r fe, right femur; r hu, right humerus; r ra, right radius; r sc, right scapula; r tb, right tibiotarsus; r ul, right ulna; sk, skull elements; TEM, transmission electron microscopy. |
 |
| Reconstruction of the Jehol Biota and the well-preserved specimen of Caudipteryx. Illustration: ZHENG Qiuyang |
Xiaoting Zheng, Alida M. Bailleul, Zhiheng Li, Xiaoli Wang and Zhonghe Zhou. 2021. Nuclear Preservation in the Cartilage of the Jehol Dinosaur Caudipteryx. Communications Biology. 4: 1125. DOI: 10.1038/s42003-021-02627-8
Organic molecule remnants found in nuclei of ancient dinosaur cells
