RHAMPHORHYNCHUS

genus of extinct primitive flying reptiles found as fossils in Late Jurassic deposits (those 144 to 163 million years old) in Europe and East Africa. Rhamphorhynchus was about 0.5 m (1.5 feet) long, with a long skull and large eyes. The nostrils were set back on the beak. The teeth slanted forward and interlocked; the animal was probably a fish eater. The trunk was short, and the front limbs adapted into winglike structures; each thin wing membrane stretched from a long, strong fourth finger and probably attached near the hind limbs. The other three fingers had claws at their ends. The upper arms were strong and provided attachment for well-developed breast muscles that supported the wings in flight. The tail was very long, almost twice the length of the body, and had a rudderlike piece of skin at its end; it probably helped balance and perhaps even steer the animal while in flight. Many of the bones were hollow, an obvious advantage to a flying animal. The hind limbs were not well developed, and Rhamphorhynchus must have been awkward on the ground and inefficient in flight because the soft wing membrane was capable of only full flapping movement. Some well-preserved specimens found in fine-grained sediments show the impressions of hairlike structures, but there is no evidence of scales or feathers. How Rhamphorhynchus reproduced is uncertain; it probably laid eggs, but it is uncertain whether nesting behaviour was developed. See also pterosaur.