The Triassic and Permian

The Triassic

When: 250 to 205 million years ago.

Animals: Reptiles dominate the land, molluscs dominate the sea (brachiopods and echinoderms are now rarer).

Plants: Ferns and conifers (like pine trees) grow on land.

Firsts: The Triassic sees the first dinosaurs, pterosaurs and mammals.

Lasts: Most groups lived through the Triassic, to the Jurassic.

Notes: Britain was an arid (dry) and warm area during the Triassic, so we don't see many British Triassic fossils.

This is a fossil crinoid or sea lily. Sea lilies are echinoderms - they are related to starfish and sea urchins.

This fossil was found in Germany where it lived just over 380 million years ago.

The Permian

When: 292 to 250 million years ago.

Animals: Reptiles rise to dominate the land, but amphibians are important in wetter environments. Giant trilobites, brachiopods and corals are common in the sea.

Plants: Conifers (pine trees) become important. A plant called Glossopteris is very common in Antarctica, Australia, South Africa and South America.

Lasts: Trilobites and eurypterids die out. Many groups of molluscs, crinoids and brachiopods also become extinct.

Notes: The Permian ends in a mass extinction. An estimated 96% of marine animals with hard parts die out.

Do you know what these fossils are?

This specimen is the skull of an ancient amphibian called Trematosaurus. It probably looked like like a giant salamander or newt. It was found in Germany in rocks that formed at the beginning of the Triassic period.

This is a skeleton of an extinct animal called Procynosuchus. Although it is an ancient reptile it is not a dinosaur. Procynosuchus was a mammal-like reptile, and it was from this type of reptile that all mammals (including humans like you) evolved. This skeleton was found in Zambia in Africa and is from the Permian period, about 255 million years old.

This is a fossil ammonoid - an extinct mollusc that floated through the seas in its coiled shell. It was found in France in rocks that formed in the Triassic period, over 225 million years ago.

This is a polished slab of a petrified wood. It was found in Arizona in America and came from a conifer (a tree like a pine tree) that grew in the Triassic period.

Each year a tree grows by adding a layer of wood to its trunk and branches. By counting the tree rings in a piece of fossilised wood we can work out how old it was when it died.
How old do you think this tree was when it died?

This is the femur (leg bone) of a dinosaur called Plateosaurus. It was found in Germany, and came from a plant-eater that probably grew up to eight metres long. Plateosaurus was an early type of dinosaur that lived in the Triassic period about 220 million years ago.

These are fossil bivalve molluscs that look just like some of the shells you may find on the beach today. They were found in County Durham and are from the Permian period, just over 250 million years old.

This is a type of mollusc called a nautiloid. Nautiloids are related to ammonites and other animals like squid. They were once common, but now only a few types live in seas around the world. This one was found in County Durham and is from the Permian period, just over 250 million years old.

These are fossil brachiopods. Although they look like the shells of bivalve molluscs like cockles and mussels, they are actually from very different animals. These ones were found in Texas in America and are from the Permian period, about 275 million years old.

These are fossil corals. These ones were found in Texas in America and are from the Permian period, about 275 million years old. At this time Texas was covered in warm tropical seas that allowed the growth of coral reefs.

This is the fossil of a fish that looks quite like the ones you would see swimming in the oceans today. This one was found in County Durham and is from the Permian period, just over 250 million years old.