Turrilites

Turrilites is a genus of helically coiled ammonoid cephalopods from the lower part of the Upper Cretaceous (Cenomanian and Turonian); generally included in the Ancyloceratina. Previously (Arkell, 1957) it was included in the ammonoid suborder, Lytoceratina.

Turrilites Temporal range:
Turrilites costatus from Rouen, France, on display at Galerie de paléontologie et d'anatomie comparée, Paris
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Suborder:	†Ancyloceratina
Family:	†Turrilitidae
Genus:	†Turrilites Lamarck, 1801

The shell of Turrilites is tightly wound in a high trochospiral, with an acute angle at the apex. Ribs are weak to strong and may have 3 or 4 rows of equal numbers of tubercles. Thought to be derived from Mariella. Includes three subgenera.

Subgenera and species

Turrilites has three subgenera.

• Turrilites (Turrilites) Lamarck, 1801
  • Turrilites (Turrilites) acutus Passy, 1832
  • Turrilites (Turrilites) costatus Lamarck, 1801
  • Turrilites (Turrilites) scheuchzerianus Bosc, 1801
• Turrilites (Euturrilites) Breistroffer, 1953
• Turrilites (Mesoturrilites)

Subgenus Turrilites has weak ribs and strong tubercles. Subgenus Euturrilites has strong ribs, commonly depressed in middle, especially on early whorls, and no tubercles. Subgenus Mesoturrilites has almost no ribs and clavate tubercles that tend to form spiral ridges.

References

• Arkell et al., Mesozoic Ammonoidea (L222); Treatise on Invertebrate Paleontology Part L, Ammonoidea. Geological Soc. of America and Univ Kansas Press.
• The Paleobiology Database Turrilites entry