Hildoceratoidea

Hildoceratoidea
Temporal range: Early—Middle Jurassic, Pliensbachian–Bajocian
Harpoceras
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: †Ammonoidea
Order: †Ammonitida
Suborder: †Ammonitina
Superfamily: Hildoceratoidea
Hyatt, 1867
Families

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.[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 Eoderoceratacean family, Polyorphitidae. The Stephanocerataceae, Perisphinctaceae, and Haplocerataceae have their source in the Hammitoceratidae which is derived from the Hildoceratidae .[2]

Approximate timeline of Hildoceratoidea families with their evolutionary relationships.

References

  1. ↑ Kovács, Z.; Géczy, B. (2008). "Upper Toarcian – Middle Aalenian (Jurassic) Erycitinae SPATH (Ammonitina) from the Gerecse Mts, Hungary" (PDF). 125th Anniversary of the Department of Palaeontology at Budapest University – A Jubilee Volume Hantkeniana. 6: 57–108.
  2. 1 2 3 Arkell et al, Treatise on Invertebrate Paleontology, Part L Ammonoidea, (1956)
  3. ↑ Taxonomicon (Hildocerataceae)|
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