Spitidiscus
| Spitidiscus Temporal range: Hauterivian - Barremian | |
|---|---|
 | |
| Fossil shell of Spitidiscus species from Alpes-de-Haute-Provence, on display at Galerie de paléontologie et d'anatomie comparée in Paris | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Order: | Ammonitida |
| Family: | Holcodiscidae |
| Genus: | Spitidiscus Kilian, 1910 |
Spitidiscus is an ammonite genus placed in the family Holcodiscidae.
Species
- Spitidiscus kilapiae Rawson and Aguirre-Urreta 2012
- Spitidiscus oregonensis Imlay 1960
- Spitidiscus simitiensis Haas 1960
Description
Member species have a rather evolute shell in which the whorl section is more or less circular, venter broadly rounded and dorsum fairly deeply impressed. Close, fine low, single or rarely branching ribs are interspersed by frequent straight or slightly sinous, moderately deep but wide constrictions.
Geologic Time Scale
The first appearance of the species Spitidiscus hugii or Spitidiscus vandeckii are proposed to be the marker for the beginning of the Barremian.[3]
Distribution
Spitiduscus has been found in the Lower Cretaceous of Europe (Czechoslovakia, France, Italy, Portugal, Spain, Russia), as well as of Morocco, Argentina, Colombia and Mexico. [2] The type species S. rotulia is from the Hauterivian of England.
References
- ↑ Sepkoski, Jack Sepkoski's Online Genus Database – Cephalopoda
- ↑ 2.0 2.1 The Paleobiology Database
- ↑ "GSSP Table - Mesozoic Era". Geologic Time Scale Foundation. Retrieved 15 January 2014.
- W.J. Arkell, et al, 1957. Mesozoic Ammonoidea Treatise on Invertebrate Paleontology, Part L, Ammonoidea. Geological Society of America and Univ Kansas Press.