Archaeopteryx of "Archaeopteryx" bones appear poorly vascularized; in living vertebrates, poorly vascularized bone is correlated with slow growth rate. They also assume that all known skeletons of "Archaeopteryx" come from juvenile specimens. Because the bones of "Archaeopteryx" could not be histologically sectioned in a formal skeletochronological (growth ring) analysis, Erickson and colleagues used bone vascularity (porosity) to estimate bone growth rate. They assumed that poorly vascularized bone grows at similar rates in all birds and in "Archaeopteryx". The poorly vascularized bone of "Archaeopteryx" might have grown as slowly as that in a mallard (2.5 micrometres per day) or as fast as
Ruppert Archaeopteryx Ruppert Archaeopteryx The Ruppert Archaeopteryx () is a Swiss high-wing, pod-and-boom, single-seat, microlift glider that was designed by Roger Ruppert and is produced by Ruppert Composite GmbH. The aircraft is named for the feathered Archaeopteryx dinosaur. The Archaeopteryx was conceived as a foot-launchable microlift sailplane, with the design goals of a light empty weight, low stall speed with gentle stall characteristics, good maneuverability and good high speed performance. A further goal was a sailplane that could be foot-launched in zero wind conditions. The Archaeopteryx design started in 1998 at the Zurich University of Applied Sciences (ZHW) as a research project.