''Shastoceras'' is a genus of extinct ammonites found in Lower Aptian sediments in Northern

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. Although sometimes placed in the Heteroceratidae, a family characterized by a helically wound early portion, its form indicates it more likely belongs to the Ancyloceratidae. ''Shastoceras'' resembles '' Uhligia'' from the Lower

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is precede ...

of Germany, except for being stouter. In both genera the initial portion is short and in general straight, followed by a more or less 180 deg. bend and a straight to moderately curved shaft ending in a hook. The shaft of ''Shastoceras'' is shorter and broader than that of ''Uhligia''.

References

* W.J. Arkell, et al., 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L. Geological Society of America and University of Kansas Press. Ammonitida genera Early Cretaceous ammonites Ammonites of North America Ancyloceratoidea {{ammonite-stub