Berriasella jacobi
| Berriasella jacobi Temporal range:
| |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | †Ammonoidea |
| Order: | †Ammonitida |
| Family: | †Neocomitidae |
| Genus: | †Berriasella |
| Species: | †B. jacobi
|
| Binomial name | |
| †Berriasella jacobi Mazenot 1939
| |
Berriasella jacobi is an extinct species of ammonite from the late Jurassic and early Cretaceous.[1] Because of its unique stratigraphic position, it is used as an index fossil to determine the boundary of the Cretaceous and Jurassic periods. The Berriasella jacobi zone defines the substage of the Lower Berriasian, the Berriasian being the lowest stage of the Cretaceous.[2] However, due to the species limited geographic distribution, several other candidates have also been nominated, including Calpionella alpina.
References
- ^ "Berriasella jacobi". mindat.org. Retrieved 2022-11-11.
- ^ Zakharov, Viktor A.; Bown, Paul; Rawson, Peter F. (1996). "The Berriasian Stage and the Jurassic-Cretaceous boundary" (PDF). Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre. 66.