Prolobitidae is a family of middle and upper

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, w ...

ammonoid Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefi ...

cephalopods A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

currently included in the goniatitid suborder Tornoceratina and superfamily

Dimeroceratoidea Dimeroceratoidea, formerly Dimerocerataceae, is one of six superfamilies in the goniatitid suborder Tornoceratina which lived During the Devonian. Five families are included, the Dimeroceratidae being the type family. Gonitites, to which they ...

, but previously included in the ancestral

Anarcestida Agoniatitida, also known as the Anarcestida, is the ancestral order within the cephalopod subclass Ammonoidea originating from bactritoid nautiloids, that lived in what would become Africa, Asia, Australia, Europe, and North America during the ...

. Prolobitids are characterized by goniatic sutures with an undivided ventral lobe and primary lateral lobes that are introduced in the umbilical region. They have shells which are discoidal to subglobular, some bearing transverse ribs and the umbilicus is generally moderate to closed. Prolobitidae is divided into two subfamilies,

Prolobitinae Prolobitinae is one of two subfamilies of the Prolobitidae family, a member of the Goniatitida order. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopodes, and cuttlefish, and more distant ...

consisting of subglobular to subdiscoidal shells with moderate to closed umbilici, and

Raymondoceratinae Raymondoceratinae is one of two subfamilies of the Prolobitidae family, a member of the Goniatitida order. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopodes, and cuttlefish, and more di ...

consisting of discodal shells with transverse ribs and large umbilici. The Prolobitidae have been considered the likely ancestors for

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 ...

References

* Miller, Furnish, and Schindewolf,1957; Paleozoic Ammonoidea, Suborder Anarcestina, L29-L33, in The Treatise on Invertebrate Paleontology, Part L, Ammonoidea.
The Paleobiology Database
as of 10/01/07 Goniatitida families Dimeroceratoidea Middle Devonian first appearances Late Devonian animals Late Devonian extinctions {{Goniatitida-stub