Stenopopanoceras

Stenopopanoceras
Temporal range: Anisian
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ceratitida
Superfamily: Megaphyllitoidea
Family: Parapopanoceratidae
Genus: Stenopopanoceras
Popov, 1961

Stenopopanoceras is an involute, discoidal ceratitid ammonite from the Middle Triassic that has been found on Spitsbergen and in arctic Russia and British Columbia. The name, Stenopopanoceras, indicates that its shell as compressed, relatively thin; involute as for the family. The siphuncle is ventral throughout, unlike Parapopanoceras where in the siphuncle starts off more centrally located and migrates within the fist few whorls to become ventral. Septal necks start off retrochoanitic, pointing to the rear, but by the beginning of the third whorl are prochoanitic, forward pointing.

Related general include Amphipopanoceras and Parapopanoceras.

References

This article is issued from Wikipedia - version of the Saturday, November 14, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.