Pterosaurs: dragons of the air

Silurian: life colonises the land

The Silurian was an eventful time in the evolution of terrestrial life. The first freshwater animals are found in Silurian lake and river deposits, while the first very small vascular plants are found on land. Vascular plants are plants with tubes for getting water from roots to leaves. All plants except algae and liverworts are vascular plants.

This period also sees the first fossils of terrestrial animals. These early land animals, like the plants, were small and usually no longer than 2-3mm. They include now extinct animals related to spiders called trigonotarbids (please see below for more information), while circumstantial evidence strongly suggests wingless insects may have been present.

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

Trigonotarbids

Trigonotarbids were an extinct group of arthropods related to spiders and scorpions. They were among the very first fully terrestrial animals. Most were just a few millimetres long. They have been found in Silurian strata of the Welsh Borders.

Image courtesy of Dr Jason Dunlop, Museum für Naturkunde, Berlin