Echioceratidae

Echioceratidae is an extinct family of ammonites that lived during Sinemurian stage of Early Jurassic.[1]

Echioceratidae
Temporal range: Sinemurian, [1]
Fossil shells of Echioceras raricostatum from Pierreclos (France), on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: †Ammonoidea
Order: †Ammonitida
Suborder: †Ammonitina
Superfamily: †Psiloceratoidea
Family: †Echioceratidae
Buckman, 1913

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. [1]

Genera and subgenera

Following genera are members of this family:[1]

  • 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.[2][1]

References
  1. M. K. Howarth 2013. Treatise on Invertebrate Paleontology, Part L, Revised, Volume 3B, Chapter 4: Psiloceratoidea, Eoderoceratoidea, Hildoceratoidea.
  2. The Paleobiology Database


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