| Arcticoceras Temporal range: Bathonian [1] | |
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| Arcticoceras cranocephaloides fossils at the Geological Museum in Copenhagen | |
Fossil | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Ammonoidea |
| Order: | Ammonitida |
| Superfamily: | Stephanoceratoidea |
| Family: | Cardioceratidae |
| Subfamily: | Arctocephalitinae |
| Genus: | Arcticoceras [2] Spath,(1924) |
Arcticoceras is an extinct ammonoid cephalopod genus from the late Middle Jurassic belonging to the ammonite family Cardioceratidae, more commonly found to high northern latitudes.
Ammonoids are an extinct group of marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids than they are to shelled nautiloids such as the living Nautilus species. The earliest ammonites appear during the Devonian, and the last species died out in the Cretaceous–Paleogene extinction event.
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174 to 163 million years ago. Fossil-bearing rocks from the Middle Jurassic are relatively rare, but some important formations include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland, the Daohugou Beds in China, Itat Formation in Russia, and the Isalo III Formation of western Madagascar.
The Arcticoceras shell is involute, inner whorls sharply ribbed, outer ones becoming smooth. [3] The suture, following the description of the Stephanoceratoidea, is complex, ammonitic, with a dominant 1st lateral lobe and well-developed umbilical lobe. May be derived from Arctocephalites .
Arctocephalites is an extinct ammonitic cephalopod genus from the Middle Jurassic with a wide northern distribution belonging to the stephanoceratacean family, Cardioceratidae.
Arcticoceras is found in northern Alaska, arctic Canada, Greenland, northern and central Russia, as well as in Wyoming, North Dakota, and Utah. [3] Part of the fauna that lived in high latitude (arctic and subarctic) marine waters during the second half of the Middle Jurassic.
Arcticoceras kochi and A ishmanae have been found in the boreal Bathonian stage of central East Greenland. Arcticoceras and Arctocephalites are found the Volga River Basin, Sartov Region, and Arctocephalites in the Pechora River Basin indicating an earlier and deeper penetration of arctic water into European Russia than previously thought. [4]
