180 Million Years of Pterosaur Rise and Decline: A Long Waning Phase Beginning in the Early Cretaceous

Pterosaurs survived from the Triassic until the end of the Cretaceous, spanning nearly 180 million years of evolutionary history. During this immense interval, some species remained very small, whereas others evolved into giants with enormous wingspans. Their teeth, cranial crests, wings, and limbs also underwent extensive morphological change. A large-scale analysis of pterosaur macroevolution suggests that they experienced a flourishing period lasting about 115 million years, followed by a roughly 65-million-year waning period beginning in the Early Cretaceous, before finally disappearing in the Cretaceous–Paleogene extinction event.

Determining whether a group was flourishing or declining cannot reliably be done simply by counting how many fossil species are known from each interval. Whether fossils were preserved, which rock formations are exposed at the surface, and where paleontologists have collected fossils can all affect the number of species we recover. The study therefore examined several different aspects of pterosaur evolution at the same time. These included the net diversification rate, the difference between speciation and extinction rates; the rate at which body morphology changed; the extent of the morphospace occupied by different species, which reflects how morphologically different they were from one another; and changes in body size through time.