Haploceras is a genus of late Upper Jurassic (Kimmeridgian and Tithonian) ammonoid cephalopods and the type for the Haploceratidae, similar to Lissoceras but with a broader whorl section and small blunt lappets and a blunt rostrum; some species with feeble ventral folds on body chamber.
Distribution Jurassic deposites in North America, Africa, Europe and the mid east.
References
Arkell et al., 1957 Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology Part L. Geol Society of America and Univ Kansas Press R.C Moore (ed)