Racking brain over 2 Fulgoraria species

[sakura-of-the-sea]

I recently obtained 4 of a Fulgoraria genus but cannot pinpoint which of possible two species they could be. I looked through field guides & online catalogs & see no visible difference between F. rupestris & F. hamillei, which are the only two species they could possibly be. I see they both have the same shape, similar size, location & markings & can both be variable in pattern.

This is frustrating, considering I can usually find the identity of most marine gastropods fairly quickly. And I rarely keep ones I cannot positively identify. Any minute details I may have missed to tell the two species apart? Thanks for your help.  <span class="petit">--Last edited by sakura-of-the-sea on 2009-05-20 08:34:12 --</span>