| Fossil range | Early—Middle Jurassic, |
|---|---|
| Taxon | Hildoceratoidea |
| Authority | Hyatt, 1867 |
| Subdivision ranks | Families |
| Subdivision |
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.[2]
Hildoceratoidea is an upper Lower to lower Middle Jurassic group belonging to the Ammonitina that unites the Hildoceratidae, Hammatoceratidae, Graphoceratidae, and Sonniniidae.[2] In some taxonomies the name Phymatoceratidae is substituted for the Hammatoceratidae[3]
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.[2]
References
- ^ Kovács, Z. & Géczy, B. (2008). "Upper Toarcian – Middle Aalenian (Jurassic) Erycitinae SPATH (Ammonitina) from the Gerecse Mts, Hungary". 125th Anniversary of the Department of Palaeontology at Budapest University – A Jubilee Volume Hantkeniana. 6: 57–108. Archived from the original on 2011-07-16. Retrieved 2010-11-25.
- ^ Arkell et al., Treatise on Invertebrate Paleontology, Part L Ammonoidea, (1956)
- ^ Taxonomicon (Hildocerataceae)|