Anatropites is a genus in the ceratitid

Ceratitida

The 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 ammonites....

 family Tropitidae

Tropitidae

The Tropitidae is a family of Upper Triassic Ammonoidea belonging to the Tropitaceae, a superfamily of the CeratitidaTropitidae have subspherical to discoidal, involute to evolute shells with long body chambers and a ventral keel bordered by furrows. The surface may have ribs, nodes, or spines, or...

 with spines instead of nodes on the umbilical shoulder, at least in early whorls. Ceratitids are mostly Triassic ammonoid cephalopods

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.

References

• Arkell et al. Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Ammonoidea. 1957
• Paleobio Anatropites