Late Cambrian – Early Triassic
Bellerophontidae is an extinct family of slow-moving low-level epifaunal detritovores
Description of the Family
- Coil narrow
- Wide umbilici
- Slit deep
- Perietal lip generally reflexed
- Shell rounded, in many cases inflated; apertural margins in many cases flaring or even somewhat explanate, perietal lip generally reflexed; anteromedian slit generating distinct selenizone; umbilicus narrow or closed.
Treatise on Invertebrate Paleontology, Part I, Mollusca 1 (1960):
- Coil narrow, with wide umbilici; slit deep; commonly with a definite posterior train
Ulrich & Scofield (1897):
- Symmetrically involute shells, the whorls enlarging rapidly, the mouth generally expanded laterally and ventrally, not dorsally, the umbilicus mostly small or closed. Inner lip more or less thickened, the outer sinuate and centrally emarginate, the slit short; slit-band always present. Surface with lines of growth only, or cancellated, the revolving lines straight and never oblique with respect to the longitudinal axis of the volutions.