A mid-Cretaceous enantiornithine (Aves) hatchling preserved in Burmese amber with unusual plumage
Lida Xing, Jingmai K. O’Connor, Ryan C. McKellar, Luis M. Chiappe, Kuowei Tseng, Gang Li, Ming Bai
Summarized by Sarah Sheffield
What data was used? Newly discovered Cretaceous-age (~100-65 million years ago) amber specimens that contain parts of a bird hatchling; rarely found soft tissues of the plumage were also preserved. These specimens were found in Myanmar.
Methods: The specimens, encased in amber, were CT scanned using a micro CT scanner. Each preserved piece of the bird skeleton (e.g., neck, foot, etc.) were scanned separately. Researchers then did a 3D reconstruction of the bird, combining all of the scanned pieces.
Results: Researchers found that a number of the bones in this specimen were unfused, which indicates that the bird was very young (bones typically fuse as an organism grows-human babies do this too!). The specimen preserved two types of feathers: downy-type feathers and outer feathers, similar to birds today and to some of the earliest birds in the Jurassic, like Archaeopteryx, the famous bird-dinosaur transitional fossil.
Why is this study important? Feathers and other types of soft tissue are exceedingly rare in the fossil record! Typically, the only things that get preserved are bones, shells, and other hard tissues. Amber is one of the ways that soft tissue can be preserved; when we find soft tissue preserved, it’s certainly a reason to celebrate! This data can shed a lot of light on how organisms looked from millions of years ago. This hatching’s preservation tells us a lot about how feathers in juvenile birds looked from the Cretaceous, and can be compared to the other soft tissue feathers that have been found previously belonging to adult birds. The bones also provide more information on how skeletal changes of birds occurred from juvenile to adult stages.
The big picture: Soft tissue preservation is an incredible opportunity to learn about organisms that lived a very long time ago-other soft tissue fossils have shown us what dinosaur skin looked like, how organs of extinct mammals look, and more. As you can imagine, it’s also rare to find well-preserved juveniles in the fossil record (many groups of fossils don’t have juvenile representatives at all!), so when we do find examples of younger organisms, it’s important to study them to understand how their bodies changed throughout their lifetime.
Citation: Lida, X., O’Connor, J.K., McKellar, R.C., Chiappe, L.M., Li, G., Bai, M., 2017, A mid-Cretaceous enantiornithine (Aves) hatchling preserved in Burmese amber with unusual plumage