Kingdom Animalia Phylum Mollusca Order Prolecanitida | Superfamily Medlicottiaceae Rank Subfamily Subclass Ammonites | |
Similar Ammonites, Metalegoceras, Goniatite, Nautiloid | ||
The Medlicottiinae is a subfamily of the Medlicottiidae, a family of ammonoid cephalopods included in the Prolecanitida, characterized by having discoidal to thinly lenticular shells with a retuse (grooved) venter and sutures with bifid auxiliary lobes.
The Medlicottiinae includes, by general consensus the following five genera: Artinskia, Eumedlicottia, Medlicottia, Neogeoceras, and Syrdenites. Of these only Artinskia and Medlicottia, included in the Medlicottinae in the Treatise (Miller, Furnish, and Schindewolf, 1957) remain. Episageceras, Propinacoceras, and Sicanites, then included, have become type genera respectively for the Episageceratinae, Propinacoceratinae, and Sicanitinae.
Artinskia is the ancestral form, thought to be derived from Uddenoceras (Uddenitinae), which gave rise to the type genus Medlicottiia. Medilicottia then gave rise to Eumedlicottia and Neogeoceras. The derivation of Syrdenites is uncertain.