Hoplites
| Hoplites | ||||||||||||
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Hoplites dentatus |
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| Temporal occurrence | ||||||||||||
| Middle albium , chalk | ||||||||||||
| approx. 108 to 104 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Hoplites | ||||||||||||
| Neumayr , 1875 | ||||||||||||
| species | ||||||||||||
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Hoplites are a genus of ammonites from the Cretaceous period . It is the type genus of a larger ammonite family, the Hoplitidae .
features
The housing has a slightly narrowed, rectangular to slightly flattened trapezoidal cross-section. The genus is characterized by particularly strong and forwardly curved ribs that emanate from thickenings on the umbilical shoulders. Between these primary ribs, one or two other ribs that are slightly higher can intervene. The ribs are interrupted at the venter and are there alternating or opposing each other. They end in small nodules.
Occurrence and stratigraphic range
Representatives of the genus Hoplites are found mainly in Europe and Mexico . Another occurrence is in the Transkaspi region, the Asian side of the Caspian Sea . In terms of time, they are limited to the Middle Albium of the Cretaceous Period.
Systematics
The genus that used to be quite large and broad is now very narrow and restricted to a few species that are very closely related to the type species of the genus. The other species were assigned to new genera closely related to the genus Hoplites . The close relationship of the new genera with the old Hoplites genus is expressed with the second part of the name -hoplites, with which many of the new genera end. The genus is divided by some authors into two subgenus, the nominate subgenus Hoplites (Hoplites) Neumayr, 1875 and Hoplites (Isohoplites) Casey, 1954.
literature
- Raymond C. Moore (founder), Roger L. Kaesler (ed.): Treatise on Invertebrate Paleontology . Part L: Mollusca 4th vol. 4: Claud W. Wright , John H. Callomon , Michael K. Howarth : Cretaceous Ammonoidea. Revised edition. Geological Society of America et al., Boulder, CO et al. 1996, ISBN 0-8137-3112-7 .