180-154 Million Years Ago

The Middle Jurassic, called the Dogger in the European system of classification, is the second epoch of the Jurassic Period. It lasted from 180-154 million years ago.

During this time, marine life (including ammonites and bivalves) flourished and new types of dinosaurs evolved on land (including Cetiosaurs, brachiosaurs, megalosaurs and hypsilophodonts).

In the seas, Ichthyosaurs, although common, are reduced in diversity, while the top marine predators, the pliosaurs, grew to the size of killer whales and larger (Pliosaurus, Liopleurodon). Also in this period Pangea started to separate.

The Middle Jurassic period was split into four sub divisions:

Aalenian - a subdivision of the Middle Jurassic epoch of the geologic timescale that extends from about 175.6 million years ago to about 171.6 million years ago.

Bajocian - this lasted from approximately 171.6 million years ago to around 167.7 million years ago.

Bathonian - this lasted from approximately 167.7 million years ago to around 164.7 million years ago.

Callovian - occurring from 164.7 to 161.2 million years ago.

It is the last stage of the Middle Jurassic.

The stage takes its name from an old spelling of Kellaways Bridge, 3 km north-east of Chippenham in Wiltshire in England.

Dinosaurs of the Middle Jurassic include:

Brachytrachelopan | Gasosaurus | Monolophosaurus | Omeisaurus

Precambrian | Cambrian | Ordovician | Silurian | Devonian | Carboniferous | Permian | Upper Triassic | Lower Jurassic | Middle Jurassic | Upper Jurassic | Lower Cretaceous | Upper Cretaceous