''Asteroceras'' ("star horn") is an extinct genus of

cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

belonging to the

Ammonite Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

subclass. These fast-moving nektonic carnivores lived during the

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

and

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 143.1 Mya. ...

periods (from 205.6 to 189.6 Ma).

Species

*'' Asteroceras blakei'' Spath, 1925 *'' Asteroceras confusum'' Spath, 1925 *'' Asteroceras obtusum'' (Sowerby, 1817) *'' Asteroceras reynesi'' Fucini, 1903 *'' Asteroceras saltriensis'' Parona, 1896 *'' Asteroceras smithii'' (Sowerby, 1814) *'' Asteroceras stellare'' (Sowerby 1815) *'' Asteroceras turneri'' (Sowerby, 1814) Paleobiology Database - Asteroceras
2014-05-29.

Distribution

''Asteroceras'' fossils may be found in the Jurassic marine strata of Canada, China, Germany, Hong Kong, Hungary, Peru, and Turkey, in the Triassic of United States and at

Lyme Regis Lyme Regis ( ) is a town in west Dorset, England, west of Dorchester, Dorset, Dorchester and east of Exeter. Sometimes dubbed the "Pearl of Dorset", it lies by the English Channel at the Dorset–Devon border. It has noted fossils in cliffs and ...

in the ''Asteroceras obtusum'' zone of Upper

Sinemurian In the geologic timescale, the Sinemurian is an age (geology), age and stage (stratigraphy), stage in the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series. It spans the time between 199.5 ±0.3 annu ...

age.Martell, D. M. 1995. An Ichthyosaur with Preserved Soft Tissue from the Sinemurian of Southern England. Palaeontology. 38(4): 897–903

References

Ammonitida genera Arietitidae Jurassic ammonites Ammonites of Europe Triassic ammonites Sinemurian life Fossil taxa described in 1867 {{Ammonitida-stub