Haploceratoidea

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

Haploceratoidea Temporal range:
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Suborder:	†Ammonitina
Superfamily:	†Haploceratoidea Zittel, 1884
Families
see text

Haploceratoidea begins with all three families in the lower Middle Jurassic, Bajocian. Strigoceratidae is limited to the Bajocian but Oppeliidae, and Haploceratidae extend through the remaining Jurassic, well into the Cretaceous; the Oppeliidae into the middle Albian, the Haplocertidae only into the Valanginian.

Diagnosis

Haploceratoidea are typically compressed, discoidal Ammontida that may be keeled or unkeeled, tending to be oxyconic, with usually falcoid or falcate ribbing. The aptychi are paired and differ between families and have been found in situ in e.g. Oppelia subrudiata and in Pseudolissoceras.

Taxonomy

The Origin of the Haploceratoidea is undetermined but it is likely all three component families have their beginnings in the Hammatoceratidae in the middle Bajocian. None of the Haploceratoidea is thought to have given rise to any subsequent group.

Superfamily Haploceratoidea Zittel, 1884

• Family Haploceratidae Zittel, 1884
  • Genus Lissoceras Bayle, 1879
  • Genus Glochiceras Hyatt, 1900
  • Genus Haploceras Zittel, 1870
  • Genus Neolissoceras Spath, 1923
• Family Oppeliidae Bonarelli, 1894
  • Subfamily Aconeceratinae (Spath, 1923)
    • Genus Aconeceras Hyatt, 1903
    • Genus Gyaloceras Whitehouse, 1927
    • Genus Koloceras Riccardi et al., 1987
    • Genus Sanmartinoceras
  • Subfamily Hecticoceratinae Spath, 1925
    • Genus Hecticoceras Bonarelli, 1893
    • Genus Pseudosonninia Parent, 2019
  • Subfamily Mazapilitinae Spath, 1928
  • Subfamily Oppeliinae Bonarelli, 1894
    • Genus Submazapilites Cantu-Chapa, 1962
  • Subfamily Streblitinae Spath, 1925
    • Genus Bornhardticeras Böhm & Riedel, 1933
    • Genus Cyrtosiceras Hyatt, 1900
    • Genus Substreblites Spath, 1925
    • Genus Uhligites Kilian, 1913
  • Subfamily incertae sedis
    • Genus Naramoceras McNamara, 1985
• Family Strigoceratidae Buckman, 1924
  • Genus Oecoptychius
  • Genus Phlycticeras Hyatt, 1900
  • Genus Strigoceras Quenstedt, 1886

References

• Treatise on Invertebrate Paleontology, Part L Ammonoidea, (L171), Geological Society of America and University of Kansas press, 1964.