Oppeliidae
# Oppeliidae

Oppeliidae are compressed to oxyconic, sculptured Haploceratoidea, either unkeeled, unicarinate, bicarinate, or tricarinate; with sutures in great variety, but ribbing usually more or less falcoid or falcate. The Oppeliidae is the principal family of the Haploceratoidea, with the longest duration, extending from the Middle Jurassic (Bajocian) to the Upper Cretaceous (Cenomanian) Their derivation is from the Hildoceratoidea.

## Subfamilies

Nine subfamilies are recognized, the first eight of which are included in the earlier Treatise, Part L. They are the:

    Oppeliinae
    Hecticoceratinae
    Distchoceratinae
    Teramelliceratinae
    Phlycticeratinae
    Streblitinae
    Mazapilitinae
    Aconeceratinae
    Binneyitinae

The Binneyitinae was added by Donovan et al, 1981, transferred from the Stephanoceratoidea.

