Pteranodon (Cretaceous)

Pteranodon is a genus of terror-saur which lived about 86 million years ago on the North America territory. The first fossils of flying reptile were recovered in 1870, in western Kansas by Yale University expedition. Interestingly enough that being the size of a large cat, its wingspan could reach 7 metres. Today only four types of Pteranodon species are known: P. Occidentalis (western), P. Ingens (the largest), P. Longiceps (the smallest) and Pteranodon sternbergi with vertical crest.
The unique feature of Pteranodon distinguished it from Rhamphorhynchus and pterodactyl was its lack of teeth. . As such the diet included fish which was caught whilst in the water as the reptile was on the wing. . Moreover, Pteranodon males and females had long cranial crest. These crests consisted of skull bones projecting upward and backward from the skull.
The scientists suggested several theories regarding the crest function. One is that it was used for maneuvering in the air. It seemed to be true. However, the females’ crest was directed upward while the males one - backward. It was also assumed that the crest did function as an effective aerodynamic counterbalance. Nevertheless, this theory was also disputed as the large crest of Pteranodon sternbergi had a negative effect on the head balance making flight difficult. The third theory included temperature regulation function but was also disputable as well because no extra vascular system was ever detected in the crest.