''Protetragonites'' is an extinct genus of ammonoid cephalopods belonging to the family
Lytoceratidae
Lytoceratidae is a taxonomic family of ammonoid cephalopods belonging to the suborder Lytoceratina, characterized by very evolute shells that generally enlarge rapidly, having whorls in contact but mostly overlapping very sightly, or not at all. ...
. These fast-moving nektonic carnivores
[ lived from the ]Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
period Tithonian
In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the K ...
age to the Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
period Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...
age.[Sepkoski, Jac]
Sepkoski's Online Genus Database – Cephalopoda
/ref>
Species
[
* ''Protetragonites crebrisulcatus'' Uhlig, 1883
* ''Protetragonites obliquestrangulatum'' (Kilian, 1889)
* ''Protetragonites quadrisulcatus'' d'Orbigny, 1841
* ''Protetragonites zuegeli'' Maisch & Salfinger-Maisch, 2016
]
Description
Shells of ''Protetragonites'' species reach a diameter of about . Shells show few constrictions and a circular or triangular section.
/ref>
Distribution
Fossils of species within this genus have been found in the Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
rocks of Austria, Canada, Czech Republic, Slovakia, Dominican Republic, France, Hungary, Madagascar, Morocco, Poland, Spain, Russia, Ukraine, Western Sahara, as well in the Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
of Germany, Hungary and Italy.[
]
References
External links
Lithotheque.France
Jurassic ammonites
Cretaceous ammonites
Ammonites of Europe
Tithonian first appearances
Early Cretaceous genus extinctions
Ammonitida genera
Lytoceratidae
{{ammonitida-stub