Haploceratoidea

Haploceratoidea
Temporal range: Bajocian–Albian
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: †Ammonoidea
Order: †Ammonitida
Suborder: †Ammonitina
Superfamily: †Haplocerataceae
Zittel, 1884
Families

see text

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

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 Haplocerataceae is though to have given rise to any subsequent group.

Superfamily Haplocerataceae Zittel, 1884

References

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