Hildoceratoidea, formerly Hildoceratacaea, 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.Arkell ''et al.'',

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953–2007 by the Geological Society of America and the University of Kansas, then 2009–present by the University of Kansas Paleontological Institute, is a definitive multi-authore ...

, Part L Ammonoidea, (1956) 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 HammatoceratidaeTaxonomicon (Hildocerataceae),
/ref> Hildoceratidae, which is the ancestral family, is derived from the Acanthopleuroceratinae, a subfamily in the

Eoderoceratoidea Eoderoceratoidea is a superfamily of true ammonites (suborder Ammonitina) from the Lower Jurassic, comprising seven phylogenetically related families, characterized in general by having ribbed evolute shells that commonly bear spines or tubercle ...

n family, Polyorphitidae. The

Stephanoceratoidea Stephanoceratoidea, formerly Stephanocerataceae, is a superfamily of middle- upper Jurassic ammonoid cephalopods within the order Ammonitida containing diverse forms, generally with sharp ribbing and complex suture lines. Aptychi are believed ...

Perisphinctoidea Perisphinctoidea, formerly Perisphinctaceae, is a superfamily of Middle Jurassic (Bajocian) to Lower Cretaceous (Barremian) Ammonitina, ammonites, commonly with evolute shells with strong ribbing that typically divides about mid flank before cro ...

, and

Haploceratoidea Haploceratoidea, formerly Haplocerataceae, is an extinct superfamily of Ammonoidea, ammonoid cephalopods belonging to the Ammonitida that unites three families, Strigoceratidae, Oppeliidae, and Haploceratidae, listed below. Haploceratoidea begins ...

have their source in the Hammatoceratidae which is derived from the Hildoceratidae. Hildoceratoidea

References

Jurassic ammonites Ammonitida superfamilies Ammonitina Early Jurassic first appearances Middle Jurassic extinctions {{Ammonitina-stub