Sexual dimorphism ofPteranodonand other pterosaurs, with comments on cranial crests

Abstract

ABSTRACT Metric data from the large collection of the Late Cretaceous pterosaur Pteranodon are bimodally distributed with a more numerous small size-class and a less numerous large size-class. The size-classes differ in cranial crest and pelvic structure. The small size-class has small cranial crests and deep puboischiadic plates that produce a large pelvic canal, while the large size-class has large cranial crests and shallow puboischiadic plates that produce a small pelvic canal. The difference in pelvic structure suggests that the small size-class is female. The various functions proposed for cranial crests are reviewed, and it is concluded that none can account for the difference in crest size. The conclusion is that the large crests of males are display structures.