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.
| Jurassic period | ||
|---|---|---|
| Lower/Early Jurassic | Middle Jurassic | Upper/Late Jurassic |
| Hettangian | Sinemurian Pliensbachian | Toarcian |
Aalenian | Bajocian Bathonian | Callovian |
Oxfordian | Kimmeridgian Tithonian |