Caudipteryx (kaw-DIP-tear-ricks) is a small two-legged theropod dinosaur that’s about the size of a modern-day peacock. It lived around 124 million years ago during the early Cretaceous period, and its remains have been found in the area surrounding northeastern China.
These dinosaurs appeared to be nimble individuals, as is what appears to be the case with small dinosaurs around their size. Caudipteryx was thought to have been omnivorous, given its striking similarities with living avian dinosaurs, also known as birds. Like most maniraptorans, like itself and perhaps the more famous Archaeopteryx, it appeared to be an odd mix between a dinosaur and a bird. It clearly had feathers, yet it also had a pretty dinosaur-like snout with some teeth in it. It also had a tail, reminiscent of theropod dinosaurs like T. rex and cousins—yet the tail itself was tipped with stiffened bone, analogous to the fused bone now found in all living birds, called a pygostyle.
Caudipteryx’s initial finding would prove to be a one-of-a-kind fossil find, yet it somehow hasn’t run out of surprises; another specimen, also found in Liaoning province in China, would contain one of the most spectacular finds in paleontology: dinosaur cells, locked in time and preserved for at least 125 million years. The study, by a team of scientists from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences and from the Shandong Tianyu Museum of Nature (STM), was published in the journal Communications Biology.
In the study, the team obtained pieces of the fossil from what would be its right femur. Afterwards, the team decalcified the specimen, removing minerals and allowing the team to access its prized remnant proteins. In doing so, the team realized that nearly all the cells of this Caudipteryx specimen were preserved via silicification after the specimen’s death, making way for the exquisite preservation of cells.
“Geological data has accumulated over the years and shown that [its] fossil preservation […] was exceptional due to fine volcanic ashes that entombed the carcasses and preserved them down to the cellular level,” said co-author and IVPP associate professor LI Zhiheng.
From here, the research team isolated a couple of cells for analysis. Here, they applied hematoxylin, a chemical all too common in biological laboratories, to these preserved cells. Hematoxylin is used in laboratories as a histologic stain, and is known to stain cell nuclei.
Remarkably, the team found a single cell to have been stained purple due to the hematoxylin; according to Zhiheng and team, this means this single preserved dinosaur cell preserved enough original biomolecules that hematoxylin stained it anyway. It even contained traces of dark purple threads in the staining—a sign of the presence of chromatin threads, the researchers say.
Chromatin threads within cells are made of DNA molecules bundled together. It appears that the team has tantalizing preliminary data on their hands that may suggest the presence of preserved 125 million-year-old DNA in the Caudipteryx cell—a “holy grail” find for paleontology. However, to prove their results further, Zhiheng and team need to analyze their specimen more thoroughly, and must use all the tools they have at their disposal to prove once and for all if they found the sought-after dinosaur DNA. This will prove to be quite the challenge, as the oldest DNA ever sequenced are from fossils not much older than a million years old; this Caudipteryx fossil is at least 125 times older than that.
Said Alida Bailleul, lead author of the study and also from IVPP: “Let’s be honest—we are obviously interested in fossilized cell nuclei because this is where most of the DNA should be if DNA was preserved. […] So, we have good preliminary data, very exciting data, but we are just starting to understand cellular biochemistry in very old fossils. At this point, we need to work more.”
In the future, Bailleul and Zhiheng, together with the research team, hope to find out what exactly did their hematoxylin detect and stain as biological molecules, and whether or not they truly contain the long-sought ancient dinosaur DNA. For now, dreams of replicating movies like Jurassic Park in real life must remain as such.
(For more special finds in paleontology, check out our previous piece on a remarkable turtle egg fossil find that’s also from China.)
References
- Chinese Academy of Sciences. (2021a, September 24). Organic molecule remnants found in nuclei of ancient dinosaur cells. Chinese Academy of Sciences. https://english.cas.cn/newsroom/research_news/life/202109/t20210924_284183.shtml
- Chinese Academy of Sciences. (2021b, September 25). Potential remnants of original dinosaur dna discovered in exquisitely preserved dinosaur cells. SciTechDaily. https://scitechdaily.com/potential-remnants-of-original-dinosaur-dna-discovered-in-exquisitely-preserved-dinosaur-cells/
- Zheng, X., Bailleul, A. M., Li, Z., Wang, X., & Zhou, Z. (2021). Nuclear preservation in the cartilage of the Jehol dinosaur Caudipteryx. Communications Biology, 4(1), 1–9. https://doi.org/10.1038/s42003-021-02627-8
