Septimaniceras

Septimaniceras
Temporal range: Toarcian

[1]

Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: †Ammonoidea
Order: †Ammonitida
Family: †Dactylioceratidae
Subfamily: †Dactylioceratinae
Genus: †Septimaniceras
Fauré, 2002
Type species
Ammonites zitteli
Oppel, 1862
Species
  • S. zitteli Oppel, 1862
  • S. nicklesi Guex, 1971
  • S. pseudoyoungi Guex, 1972

Septimaniceras is genus of ammonites that has probably evolved from Peronoceras and lived during the midde Toarcian stage of early Jurassic. Members of this genus existed from Bifrons Subzone to lower part of Variabilis Subzone. Their fossils were found in France, Hungary and probably also in Austria.[2]

Description

Ammonites belonging to this genus have evolute shells of small size. Inner whorls are cadicone, while outer whorls are subquadrate. On younger whorls, ribs are widely spaced and are of 2 types. Bold ribs have large ventrolateral tubercules, while fine striate ribs exists between them. Later, single and looped ribs with ventrolateral tubercules on later ones are alternating.[2]

References

  1. ↑ M. K. Howarth 2013. Treatise on Invertebrate Paleontology, Part L, Revised, Volume 3B, Chapter 4: Psiloceratoidea, Eoderoceratoidea, Hildoceratoidea.
  2. 1 2 KOVÁCS, Z. (2014). Toarcian Dactylioceratidae (Ammonitina) from the Gerecse Mts (Hungary). Hantkeniana, 9, 45-77.


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