''Anatropites'' is a genus of

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) ...

in the

ceratitid Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post Triassic ammoni ...

family

Tropitidae The Tropitidae is a family of Upper Triassic Ammonoidea belonging to the Tropitoidea, a superfamily of the Ceratitida Tropitidae have subspherical to discoidal, involute to evolute shells with long body chambers and a ventral keel bordered by fur ...

with spines instead of nodes on the umbilical shoulder, at least in early whorls.Arkell et al. Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Ammonoidea. 1957 Ceratitids are mostly Triassic

ammonoid 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) ...

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

. ''Anatropites'' comes from British Columbia in Canada, Oregon and California in the United States, and Indonesia. The shell is in general evolute, but deeply impressed along the inner, or dorsal, margin. The whorl section is broad with flanks converging on a gently arched venter that bears a median keel.Paleobio Anatropites
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References

Tropitidae Ceratitida genera Triassic ammonites of North America Late Triassic life Fossil taxa described in 1893 {{Ceratitida-stub