What is "stephanoceratidae"

Stephanoceratidae is a family of planulate and coronate ammonites within the Stephanocerataceae. Shells are evolute so that all whorls are exposed and have strong ribbing that bifurcates, that is splits in two, on the flanks. Many have tubercles at the point of bifurcation. Whorl sections are generally subequant; the outer rim, or venter, commonly rounded.

The Stephanoceratidae are derived from the Otoitidae. Their fossils are found in upper Middle- and lower Upper Jurassic sediments.