What is "hildoceratoidea"

Hildoceratoidea, formerly Hildocerataceae, is a superfamily of compressed or planulate ammonites, some tending to develop acute outer rims; generally with arcuate or sigmoidal ribs. Aptichus were found in place are double-valved.

Hildoceratoidea is an upper Lower- to lower Middle Jurassic group belonging to the Ammonitina that unites the Hildoceratidae, Hammatoceratidae, Graphoceratidae, and Sonniniidae. In some taxonomies the name Phymatoceratidae is substituted for the Hammatoceratidae

Hildoceratidae, which is the ancestral family, is derived from the Acanthopleuroceratinae, a subfamily in the Eoderoceratacean family, Polyorphitidae. The Stephanocerataceae, Perisphinctaceae, and Haplocerataceae have their source in the Hammitoceratidae which is derived from the Hildoceratidae .