Distinguishing features: Parent taxon (Heterohelix): Initially planispiral, final 1 or 2 pairs of chambers subtriangular with a short blunt spine. This taxon: Specimens which cannot be assigned to established species
Emended description: Morphology: Wall type: Size:
Geological Range: Last occurrence (top): within (-Ma, top in "Holocene" stage). First occurrence (base): within (-Ma, base in "Holocene" stage).
Plot of range and occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Histogram - Neptune occurrence data from DSDP and ODP proceedings. Pale shading <50 samples in time bin. Interpret with caution & read these notes