Ussuritidae

Ussuritidae are ancestral, Triassic, Phylloceratina characterized by generally smooth, discoidal, evolute shells with rounded venters and little or no ornamentation and by sutures with primitive monophyllitic saddles with a single terminal branch or leaflet.^[1]

Ussuritidae Temporal range: Triassic
Fossil of Monophyllites sphaerophyllus from Bosnia, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Suborder:	†Phylloceratina
Family:	†Ussuritidae Hyatt, 1900

The Ussuritidae are most likely derived from the Dieneroceratidae^[1] and give rise to the Discophyllitidae. Seven genera are included:

• Ussurites
• Palaeophyllites
• Monophyllites
• Majsvarites
• Leiophyllites
• Eopsiloceras
• Eophyllites

Genera are distinguished on the basis of shell morphology and characteristics of the suture.^[1]

Ussuritidae are also known as the Monophyllitidae, a junior synonym. Palaeophyllitidae, for Palaeophyllites, is sometimes found in the literature.^[2]

References

1. Treatise on Invertebrate Paleontology Part L Mollusca 4, Ammonoidea
2. Paleobiology Database