Berriasella is a discoidal evolute perisphinctacean ammonite, and type genus for the neocomitid subfamily Berriasellinae. Its ribbing is distinct, consisting of both simple and bifurcated ribs that extend from the umbilical seam across the venter; its whorl section generally compressed, the venter more or less narrowly rounded. The species Berriasella jacobi traditionally has been regarded an index fossil defining the base of the Cretaceous, however since 2016 this had been replaced by the first occurrence of Calpionella alpina. Some authors regard B. jacobi as instead belonging to the genus Strambergella.[2]
| Berriasella | |
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| Fossil shell of Berriasella jabronensis from Gard (France), on display at Galerie de paléontologie et d'anatomie comparée in Paris | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | †Ammonoidea |
| Order: | †Ammonitida |
| Family: | †Neocomitidae |
| Subfamily: | †Berriasellinae |
| Genus: | †Berriasella Uhlig, 1905 |
| Species | |
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Berriasella, named by Uhlig, 1905, is known from the late Upper Jurassic, Tithonian, to the early Lower Cretaceous, Berriasian and has a fairly worldwide distribution.[3]
Distribution
editFossils of Berriasella have been found in:
- Jurassic
- Latady and Himalia Ridge Formations, Antarctica
- Los Molles Formation, Argentina
- Guasasa Formation, Cuba
- Chia Gara Formation, Iraq
- Muktinath, Nepal
- Punta Moreno Formation, Peru
- Hajar Formation, Yemen
- Cretaceous
- President Beaches Formation, Antarctica
- Guchuochun Formation, China
- Buenavista Breccia, Colombia
- Stramberk Formation, Czech Republic
- France
- Szentivánhegy Limestone, Hungary
- Giumal Sandstone, India
- Shal Formation, Iran
- Chia Gara Formation, Iraq
- Carbonera and Taraises Formations, Mexico
- Pieniny Limestone and Rogozno Formation, Poland
- Chigan Formation, Russia
- Tollo and Miravetes Formations, Spain
- Dvuyakornaya Formation, Ukraine
- Hajar Formation, Yemen
- Lo valdes Formation, Chile
References
edit- ^ Sepkoski, Jack (2002). "A compendium of fossil marine animal genera (Cephalopoda entry)". Bulletins of American Paleontology. 363: 1–560. Archived from the original on 2016-02-25. Retrieved 2017-10-18.
- ^ Frau, Camille; Bulot, Luc G.; Reháková, Daniela; Wimbledon, William A.P.; Ifrim, Christina (November 2016). "Revision of the ammonite index species Berriasella jacobi Mazenot, 1939 and its consequences for the biostratigraphy of the Berriasian Stage". Cretaceous Research. 66: 94–114. Bibcode:2016CrRes..66...94F. doi:10.1016/j.cretres.2016.05.007.
- ^ Paleobiology Database - Berriasella at Fossilworks.org
Further reading
edit- Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.
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