Hildoceratoidea

{{Short description|Extinct superfamily of ammonites}}

{{Automatic taxobox

| fossil_range = Early—Middle Jurassic, {{fossil range|Pliensbachian|Bajocian}}

| image = Ammonite harpoceras exaratum, 180 milioni di anni, da zona di friburgo.JPG

| image_caption = Harpoceras exaratum

| taxon = Hildoceratoidea

| authority = Hyatt, 1867

| subdivision_ranks = Families

| subdivision_ref = {{cite web | title= Paleobiology Database - Hildoceratoidea | year = | url = https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=257826| access-date = 2017-10-19 }}

| subdivision =

• Erycitidae{{cite journal |last1=Kovács |first1=Z. |last2=Géczy |first2=B. |year=2008 |title=Upper Toarcian – Middle Aalenian (Jurassic) Erycitinae SPATH (Ammonitina) from the Gerecse Mts, Hungary |journal=125th Anniversary of the Department of Palaeontology at Budapest University – A Jubilee Volume Hantkeniana |volume=6 |pages=57–108 |url=http://rogov.zwz.ru/Kovacs,Geczy,%202008_%20Erycitinae.pdf |access-date=2010-11-25 |archive-url=https://web.archive.org/web/20110716054754/http://rogov.zwz.ru/Kovacs%2CGeczy%2C%202008_%20Erycitinae.pdf |archive-date=2011-07-16 |url-status=dead }}
• Hildoceratidae
• Hammatoceratidae
• Graphoceratidae
• Sonniniidae

}}

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, 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 Hammatoceratidae[http://taxonomicon.taxonomy.nl/TaxonTree.aspx?id=114327 Taxonomicon (Hildocerataceae)|]

Hildoceratidae, which is the ancestral family, is derived from the Acanthopleuroceratinae, a subfamily in the Eoderoceratoidean family, Polyorphitidae. The Stephanoceratoidea, Perisphinctoidea, and Haploceratoidea have their source in the Hammatoceratidae which is derived from the Hildoceratidae.

File:Hildoceratoidea.svg