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, 1929Gagaticeras Buckman, 1913Plesechioceras Trueman and Williams, 1925Orthechioceras Trueman and Williams, 1925Echioceras Bayle, 1878Paltechioceras Buckman, 1924Leptechioceras Buckman, 1923- *L.
- *L. Donovan, 1966