''Cravevoceras'' is an Upper

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

ammonite in the goniatite family Cravenoceratidae, probably derived from ''

Pachylyroceras ''Pachylyroceras'' is a large, generally subglobular, Upper Mississippian gonitite and included in the cephalopod subclass Ammonoidea. Recognition ''Pachylyroceras'' produced a large shell that is moderately evolute to moderately involute and ...

'' and contemporary with other cravenoceratid genera like '' Caenolyroceras'', '' Tympanoceras'' and later ''

Alaoceras ''Alaoceras'' is an ammonoid cephalopod from the upper Paleozoic included in the goniatitid family Cravenoceratidae, named by Ruzhentsev & Bogoslovskaya in 1971. ''Alaoceras'' is characterized by its generally subdiscoidal shell with moderatel ...

'' and '' Lyrogoniatites''. It is also a member of the Neoglyphioceratoidea.

Description

The shell of ''Cravenoceras'' is thickly discoidal to globose and moderately to widely umbilicate. Young stages are mostly extremely evolute. Sculpture consists of transverse lamellae, which are more or less straight on the flanks, but form a shallow ventral sinus. Longitudinal lirae mostly absent or very faint, sometimes restricted to umbilical shoulder. Constrictions are weak or absent. The ventral lobe is narrow, with a relatively low median saddle.

Taxonomic position

The revised Treatise (Furnish et al. 2009) includes ''Cravenoceras'' in the family Cravenoceratidae and subfamily Cravenoceratinae, along with 8 other genera including '' Tympanoceras'' and '' Cravenoceratoides''. D. Korn (2006) and Saunders, Work, and Nikolaeva, 1999, along with GONIAT online give the same or a similar perspective. The older Treatise, Part L, 1957 (Miller, Furnish, and Schindewolf) on the other hand put ''Cravenoceras'' in the subfamily

Goniatitinae Goniatitinae is one of six subfamilies into which the Goniatitidae is subdivided according to Miller, Furnish, and Schindewolf, 1957. The diagnostic character is the narrow bifurcated (double pronged) ventral lobe of the suture, which lies along ...

of the goniatitacean family

Goniatitidae Goniatitidae is one of three families included in the ammonoid cephalopod superfamily Goniatitoidea, known from the Lower Mississippian to the Upper Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 millio ...

References

* W.M Furnish et al. Treatise on Invertebrate Paleontology, Part L (revised) Vo. 2 Paleozoic Ammonoidea, ..

* Miller, Furnish, and Schindewolf, 1957. Paleozoic Ammonoidea, Treatise on Invertebrate Paleontology. * Saunders, Work, and Nikolaeva, 1999. Evolution of Complexity in Paleozoic Ammonoid Sutures, Supplementary Material

GONIAT online
Mississippian ammonites Goniatitida genera Ammonites of Europe Mississippian first appearances Pennsylvanian extinctions Pennsylvanian ammonites Paleozoic life of Nunavut Cravenoceratidae {{Goniatitida-stub