Berriasella is a discoidal evolute perisphinctaceanammonite, and type genus for the neocomitid subfamily Berriasellinae. Its ribbing is distinct, consisting of both simple and bifurcated ribs that extend from the umbilical seam across the venter; its whorl section generally compressed, the venter more or less narrowly rounded. The species Berriasella jacobi traditionally has been regarded an index fossil defining the base of the Cretaceous, however since 2016 this had been replaced by the first occurrence of Calpionella alpina. Some authors regard B. jacobi as instead belonging to the genus Strambergella.[2]
Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.
