The Medlicottioidea is one of two superfamilies that make up the

Prolecanitida Prolecanitida is an order of extinct ammonoid cephalopods with discoidal to thinly lenticular shells with goniatitic or ceratitic sutures and which retained the simple retrochoanitic siphuncle with backward extending septal necks. As typical for ...

, the other being the

Prolecanitoidea Prolecanitoidea is a taxonomic superfamily of ammonites, fossil cephalopods. This is one of two superfamilies in the Prolecanitida. The other is the Medlicottioidea. The Prolecanitoidea are found in the Upper Devonian to the Middle Permian and ...

. The Medlicottioidea are recognized by their discoidal to thinly lenticular, and involute shells with small umbilici; flat, often grooved venters, and variably complex sutures. Medlicottiacean shells are often more ornamented and may sport ventrolateral nodes or ribs. The Medlicottioidea combines two related families, the ancestral Pronoritidae, descended from the Prolecanitidae in the Upper Mississippian and the derived Medlicottiidae which first appeared in the Lower Pennsylvanian. A third family, the Sageceratidae, considered to be derived from the Medlicottiidae, is included in the

Ceratitida Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from t ...

in more recent classifications. The Medlicottiaceae have become known by the alternative Medlicottiodea, following the recent ruling by the

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the Int ...

regarding superfamily endings. Medlicottiaceae nevertheless has a long standing in the literature with the taxonomic rank clear, without the need for explanation.

References

*Miller, Furnish, and Schindewolf, 1957; Paleozoic Ammonoidea, esp superfamily Medlicottiaceae, L71, in The Treatise on Invertebrate Paleontology, Part L, Ammonoidea. * Saunders and Work; Abstract: Evolution of shell morphology and suture complexity in Paleozoic prolecanitids....

Prolecanitida Prehistoric animal superfamilies Mississippian first appearances Early Triassic extinctions {{Prolecanitida-stub