''Asteroceras stellare'', the true star ammonite, is an extinct species of cephalopod belonging to the

Ammonite Ammonoids are a group of extinct 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 (i.e., octopuses, squid and cuttlefish) ...

subclass and to the family

Arietitidae Arietitidae is a family of true ammonites that make up part of the superfamily Psiloceratoidea, named after the type genus ''Arietites''. They comprise medium-size to large or gigantic genera which in general are strongly ribbed, tuberculate in s ...

.Biolib
/ref> These fast-moving nektonic carnivores lived during the lower

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, around 196.5 to 189.6 million years ago.The Paleobiology Database
/ref>

Description

''Asteroceras stellare'' has a shell reaching a diameter of about .

Distribution

Fossils of this species may be found in the Jurassic of Germany, Hungary and United Kingdom.

References

Arietitidae Jurassic ammonites {{Ammonitida-stub