Pterosaurs: dragons of the air

Ordovician: invertebrates dominate the sea

Life in Ordovician seas continued to diversify, with some arthropods reaching gigantic proportions. One arthropod group related to scorpions, the eurypterids, may have used a form of underwater flight to swim.

The Ordovician may have seen the first plants colonising the land. Evidence is sparse, with fossil spores found in Ordovician rocks in Oman appearing to be from a liverwort-like plant, but there is no certain evidence of any animals being on land.

Global reconstruction courtesy of Professor Ron Blakey, Northern Arizona University, Geology.

Image courtesy of Dr Simon Brady, University of Bristol.

Eurypterids

Eurypterids were aquatic, scorpion-like animals that may have used their expanded rear appendages as underwater wings, flying rather than rowing through the water. If so, then these ancient predators were the first animals to fly – but, like penguins, they just couldn’t fly in the air.

Sacabambaspis

Sacabambaspis is one of the earliest vertebrates. Coming from South America, this beast had no jaws and simply swam through the mud filtering out small invertebrates. Its kind eventually evolved into all of the vertebrates alive today. It is only 25cm long.

Image courtesy of Muséum national d’Histoire naturelle, Paris.