Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Spiralia
Cladus: Lophotrochozoa
Phylum: Mollusca
Classis: Cephalopoda
Subclassis: † Ammonoidea
Ordo: † Ammonitida
Subordo: †Ammonitina
Superfamilia: Psiloceratoidea
Familia: Arietitidae
Name
Arietitidae (correction by Haug, 1885, of 'Arietidae') Hyatt, 1875
References
Hyatt (1875). Proc. Boston Soc. nat. Hist. 17: 225
Haug (1885). Neues Jahrb. Min., Beil.-Band. 3: 713
Arietitidae is a family of true ammonites that make up part of the superfamily Psiloceratoidea, named after the type genus Arietites. They comprise medium-size to large or gigantic genera which in general are strongly ribbed, tuberculate in some, with keeled or grooved and keeled venters, and well differentiated ammonitic sutures. The aptycus is single valved with a shiny, concentrically striated surface.
Arietitidae dominated Lower Jurassic, Sinemurian ammonites, worldwide, extending into the lower Pliensbachian.
The Arietitidae may have their origin in the Schlotheimiidae if not directly from the Psiloceratidae, and is the probably source for the Oxynoticeratidae.
References
Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.
Donvan, D.T. and Callomon, J.H. 1981, Classification of the Jurassic Ammonitina., in The Ammonoidea, The Systematics Association Special Volume 18.
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