Nyctosaurid

Nyctosaurids are characterized by their lack of all but the wing finger. In most pterosaurs, the hand has four fingers, with the fourth elongated to support the wing, and the remaining three are usually small, clawed, and used in walking or climbing. The lack of functional fingers in nyctosaurids may suggest that they spent almost all of their time in the air, rarely walking on the ground. Nyctosaurids also possessed a distinctively enlarged crest for muscle attachment on their upper arm bone, or humerus, the deltopectoral crest, hatchet shaped like in the unrelated rhamphorhynchids. Nyctosaurids are generally characterized as specialized, pelagic soarers like frigatebirds; however, the Alcione species appear to have had shorter wings and possibly have been divers like some modern piscivorous birds.