After going unnoticed for over 140 years, a total of eight 2 cm long hatchlings were found in the fossils of the Berlin and Teylers specimens of Archaeopteryx.
The upper body of a winged and beaked animal with fossilized bones extends from the ventral side of the Berlin specimen’s thorax. Among its very small bones are elongated scapulae and hatchet-like coracoids, as seen in Archaeopteryx.
Three other beaked animals in its vicinity show surface morphology preservation, one of which is visible from head to tail, all fossilized in a clinging pose, demonstrating that Archaeopteryx hatchlings displayed clinging behavior.
Two similar animals were identified next to each other in the Teylers specimen’s fossil. One of these fossilized after dying while it was hatching from its egg. Its third wing finger crosses underneath the second as in Archaeopteryx. The other shows surface morphology preservation of the torso, head and part of one forelimb (including a finger claw), trachea, tail feathers, and structures that almost certainly correspond to both erupted and non-erupted teeth.
A disarticulated wing that is similar to that observed in one of the Teylers hatchlings was discovered in the fossil of the isolated Archaeopteryx feather, representing the first association between this isolated feather and Archaeopteryx animals.
Together with the descriptions of non-rigid eggs in Volume I and egg littering in Volume III, the still-lives of the Berlin and Teylers ground nests brought forward here enrich Archaeopteryx’s rediscovery as a nesting animal and help propel a new era of more detailed fossil analysis that may bring great contributions to evolutionary biology.