Sculpture (mollusc)
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Sculpture on a mollusc shell is the pattern or ornament of ribs, nodules, growth lines, and other distinguishing marks, which are useful in identification of the species in question.
The following are terms applicable to the sculpture of a molluscan shell:
- Axial sculpture - Sculpture running parallel to the axis of coiling. The Axis is an imaginary line through the apex of a gastropod shell, about which the whorls are coiled.
- Bead - A small hemispherical protuberance resembling a bead, similar to but smaller than a nodule.
- Beaded resembling rows or strings of beads.
- Growth Line(s) - fine transverse lines marking growth of the shell.
- Lirate - ornamented with fine thread-like lines or grooves.
- Longitudinal sculpture - following the direction of the axis of the shell.
- Nodule - A rounded protuberance on the shell sculpture; larger than a bead.
- Nodose, Nodulose or Nodular - bearing small rounded protuberances or tubercules.
- Ornament - Can refer to surface sculpture standing out in relief on shell surface; or simply to sculpture as a whole.
- Pustule(s) - very fine knob-like protrusions, smaller than a tubercule.
- Reticulate - sculpture consisting of a criss-crossing network of riblets, threads, or grooves.
- Rib - a strong ridge on the surface of the shell.
- Riblet - smaller than a rib, but coarser than a thread.
- Spiral sculpture - Sculpture following the spiral growth of the shell.
- Stria (Pl. striae) - a shallow incised groove.
- Striate - ornamented with striae.
- Thread - a very fine riblet.
- Transverse sculpture - sculpture parallel to the edge of the outer lip of the aperture.
- Tubercle(s) - Elevated knob-like projections or protrusions; larger than pustule.
- Varicose - Bearing a varix or varices.
