''Balvia'' is an
ammonoid
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...
cephalopod
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 ...
genus from the
Upper Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding Ca ...
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, and m ...
.
''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
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