I would suggest that anyone who has specimens of "Epitonium" greenlandicum
and "E" blainei and a scanning electron microscope do SEMs of these
species. What you would be looking for is micropunctation of the
intercostal surfaces.
Alex Nutzel, in his 1998 "Uber die Stammesgeschichte der Ptenoglossa
(Gastropoda) {incorrectly dated 1997 on the cover, AN perscom}, illustrates
Cirsotrema zelebori with an SEM at x130. It shows minute punctae along the
bottoms of the 2-3 striae lying between the primary spiral cords. These
punctae are far finer than those of the Opalia group.
It wouldn't be a bad idea for a wide range of eps to be SEMed for nanosculpture.
Perhaps I should examine the giant species C. lyratum likewise.
Andrew