Pterosaurs: dragons of the air
Cretaceous: pterosaurs grow huge
Taking its name from the great chalk formations of Europe, the Cretaceous was a time of rising sea levels that by the beginning of the Late Cretaceous had flooded many of the world’s largest continents. Most of Europe was inundated for much of the Late Cretaceous and great inland seas extended into the heart of Africa and North America. Much of South America was flooded too. The cause of this massive rise in sea level is attributed to rapid increases in the rate of opening of the Atlantic and other oceans, giving rise to more mid-ocean ridges, and also to increasing warming of the climate melting any ice caps that might have been present.
Global reconstruction courtesy of Professor Ron Blakey, Northern Arizona University, Geology.
This is the left humerus of Quetzalcoatlus. The part sticking out is for the attachment of flight muscles.
Where land still existed life flourished. Dinosaurs continued to diversify quite spectacularly, with the meat-eating dinosaurs achieving gigantic proportions. Spinosaurus was a 16m-long North African fish eater, while Giganotosaurus and Tyrannosaurus hunted large dinosaurs on the plains of South America and North America respectively. In the oceans long-necked plesiosaurs and ferocious pliosaurs continued to get bigger, and were joined by mosasaurs and gigantic turtles. Pterosaurs still dominated the skies, with some forms achieving gigantic proportions, including at the end of the Cretaceous the spectacular Quetzalcoatlus with a wingspan of nearly 10m. But while birds were rather scarce during the Jurassic, they diversified considerably in the Cretaceous, and were happy to share the skies with the pterosaurs, but occupied rather different ecological niches.
Mammals were diversifying too, with some happy to prey on small dinosaurs. But the end of the Cretaceous was a time of catastrophic destruction. The highly successful non-avian dinosaurs, as well as many other groups, were annihilated when a massive meteorite of between 10-30km in diameter impacted into the Yucatan peninsula. This spelled the end for pterosaurs, but not birds that remained airborne, while one group of small, insectivorous mammals eventually came to conquer the night sky.
The Early Cretaceous pterosaur, called Ludodactylus, from Brazil died when a pointed leaf became wedged between its lower jaws. This prevented the animal from feeding and the wound probably went sceptic. Did it die of starvation or septicaemia?
Photograph courtesy of Robert Loveridge