Diagnosis. – A cluster of closely spaced holes that may be circular or laterally extended into ‘furrows’ and curved, with their edges more or less in contact. All holes/furrows are more or less perpendicular to the shell surface. Holes at the centre are smaller but most
holes/furrows have a fairly constant width whereas the length may vary markedly. Most or the entire shell surface within the outline of the pedicle trace is removed.