''Balvia'' is an

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 cuttlefish) ...

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

genus from the Upper Devonian belonging to the goniatitid family

Prionoceratidae Prionoceratidae is one of seven families of the superfamily Prionoceratoidea, a member of the Goniatitida order. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish Cut ...

. ''Balvia'' has a small, lenticular to subglobular shell with a punctate umbilicus, that is completely involute. Growth lines are fine, forward slanting, concavo-convex; indicate well developed ventrolateral salients and hyponomic sinus. Flanks have several weak constrictions, which usually swing forward at venter to form grooves bounding a median keel. The aperture may be modified. ''Balvia'' was named by Dieter Korn in 1994 with the redescription of the type species, '' Gattendorfia globularis'' originally described by Schmidt in 1924. The genus was further divided into the subgenera ''B.(Balvia)'', ''B. (Mayneoceras)'', and ''B.(Kenseyoceras)'' by Becker in 1996.

References

Saunders et al 1999 Evolution of Complexity in Paleozoic Ammonoid Sutures; Supplementary Material. Science Mag.

The Paleobiology Database accessed 10/01/07
Ammonites of Europe Goniatitida genera Prionoceratidae Late Devonian ammonites {{Goniatitida-stub