The Tropitidae is a family of Upper Triassic Ammonoidea belonging to the Tropitoidea, a superfamily of the Ceratitida
Tropitidae have subspherical to discoidal, involute to evolute shells with long body chambers and a ventral keel bordered by furrows. The surface may have ribs, nodes, or spines, or may be smooth. The suture is generally ammonitic, but may be ceratitic to goniatitic.
The derivation of the Tropitidae is uncertain but they seem to form a group along with the Tropiceltitidae and Haloritidae within the superfamily.
Genera Tropididae genera included: fossilworks.org - Tropitidae page Acanthotropites Anatropites Arctotropites Arietoceltites Discotropites Euisculites Gymnotropites Homerites Homeroceras Hoplotropites Indonesites Jovites Margaritropites Microtropites Paratropites Paulotropites Platotropites Pleurotropites Sibyllites Tritropidoceras Tropites
References
Arkell et al. Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, 1957 Bernhard Kummel, 1952. A Classification of Triassic Ammonoids. Jour of Paleontology Vol. 26, No. 5, pp 847–853, Sept. 1952