This baby bird fossil gives a rare look at ancient avian development
The lack of complete breastbone suggests diversity in how some early birds developed
TINY FOSSIL The breastbone of this fossilized ancient baby bird was still mostly cartilage, rather than bone, when the bird died, meaning it wouldn’t yet have been able to fly, an analysis suggests.
F. Knoll et al/Nature Communications 2018
This baby bird had barely hatched before it died 127 million years ago — and its lack of fully developed bony breastbone, or sternum, suggests it couldn’t yet fly. The tiny fossil, just a few centimeters long, is giving paleontologists a rare window into the early development of a group of extinct birds called Enantiornithes, researchers report March 5 in Nature Communications.
Previous studies of juvenile Enantiornithes have shown that the sternums of these birds ossified in a pattern different from modern and other ancient birds. The sternum’s ossification — a process in which the cartilage is replaced by bone — is a prerequisite to withstand the stresses of flight. But which parts of the sternum fuse first varies widely among modern birds. Those patterns are reflected in modern birds’ life
