 "Deinonychus" may also display partial volancy, with the young being capable of flight or gliding and the adults being flightless.In 2018, a study concluded that the last common ancestor of the Pennaraptora had joint surfaces on the fingers, and between the metatarsus and the wrist, that were optimised to stabilise the hand in flight.This was seen as an indication for secondary flightlessness in heavy basal members of that group.