Bellerophontidae


The Bellerophontidae are an extinct family of specialized globose bellerophontids, Paleozoic and early Triassic mollusks of the class Gastropoda.

Geological range

These mollusks appeared in the Late Cambrian and continued until the Early Triassic.

Shell description

The shell resembles a miniature Nautilus, with greatly overlapping, rounded whorls, in which the last whorl completely encompasses the others, leaving either a very narrow umbilicus on either side, or none at all. At the aperture of the shell is a slit, which results in a sort of low ridge that runs along the length of shell. The shell has a low profile and these possibly were active, fast-moving molluscs.

Taxonomy

1960 taxonomy

Knight et al. 1960 in the Treatise on Invertebrate Paleontology consider the Bellerophontidae a very large family made up of a number of subfamilies and tribes.
The 1960 classification places the family Bellerophontidae in the order Bellerophontida Ulrich & Scofield, 1897.
The classification presented is:
Order Bellerophontida Ulrich & Scofield, 1897
Recently, Peter J. Wagner presented cladograms which divide this assemblage into a number of different groups, as well as combining the Bellerophontidae with the family Sinuitidae. while Bouchet & Rocroi places Sinuitidae as a family in superfamily Bellerophontoidea.

2005 taxonomy

The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005 categorizes Bellerophontidae like this:
Bouchet & Rocroi, on page 271, also state that the assignation of "symmetrical univalved mollusks "bellerophonts" either to Gastropoda or to Monoplacophora or Tergomya is controversial." In other words, it is not yet certain whether bellerophonts are in fact real gastropods, they might be monoplacophorans or they might belong to a group that is closely related to the gastropods, but not actually gastropods.

Genera

Genera in the family Bellerophontidae include:
other genera include: