The evolution and geography of Jurassic ammonoids

Ammonites are probably the most famous marine fossil of the Jurassic System, being often abundant and with a virtually global distribution where appropriate fades are preserved. Along with their fundamental role for Jurassic stratigraphy and correlation, this frequency of occurrence and wide distribution can also provide valuable insights into Jurassic marine biogeography as well as into evolutionary and other palaeobio-logical processes. In the Jurassic, up to seven suborders can be recognized: Phylloceratina, Psiloceratina, Ammonitina, Lytoceratina, Haploceratina, Perisphinctina and Ancyloceratina. Each is reviewed, citing a selection of important evolutionary case histories. These suborders range through up to about 20 distinguishable biogeographical provinces and subprovinces distributed through up to seven realm-group biochores. The latter comprise a northern, high latitude Pan-Boreal Realm or Superrealm (including the Arctic, Boreal-Pacific and Boreal-Atlantic realms/subrealms) and the low latitude and southern Pan-Tethyan Realm or Superrealm (including the Mediterran-Caucasian, East Pacific, Indo-Pacific and possibly Austral realms/subrealms).