Echioceratidae

Echioceratidae is an extinct family of ammonites that lived during Sinemurian stage of Early Jurassic.

Description
Ammonites belonging to this family are characterised by serpenticone shells with a keel, which can be surrounded by grooves if a species is densely ribbed and compressed. The whorl section is either circular or has flat sides. Ribs are simple and strong with the exception of Leptechioceras which instead possessed a strongly compressed, smooth outer whorl. The initial ontogenical stage of these ammonites is typically smooth but very short. Tubercules are represented in a few genera within this group.

Genera and subgenera
Following genera are members of this family:


 * Palaeoechioceras Spath, 1929
 * Gagaticeras Buckman, 1913
 * Plesechioceras Trueman and Williams, 1925
 * Orthechioceras Trueman and Williams, 1925
 * Echioceras Bayle, 1878
 * Paltechioceras Buckman, 1924
 * Leptechioceras Buckman, 1923
 * L. (Leptechioceras)
 * L. (Neomicroceras) Donovan, 1966

Distribution
Fossils of species within this family have been found in the Jurassic rocks of north Africa, South and North America, Europe and Asia.