Like many of you, I'm fond of the Harpa family.  Most of this family are

easy enough to readily distinguish once one examines some samples
closely.  But here's a simple question that may lack a simple answer:
how does one reliably tell the difference of Harpa major from Harpa
davidus?

I've looked over plenty of labels from my own specimens, and that
doesn't do it.  Phil Clover labels some P.I. specimens either way.  One
older book, that of Walls on Conchs and Harps, has inseparable pictures
of the two while treating H. davidus as a regional subspecies of the
very widely distributed H. major.  The pictures from Guido Poppe also
are hard to separate for these two; there's some suggestion that rib
width is always narrow in H. davidus, but lots of the P.I. and Taiwan H.

major specimens also have narrow ribs.  And as for locales, both species

appear to coincide in P.I. at least, but only H. major seems to be the
label for material from South Asia and from East Africa.  Yet I've seen
specimens apparently from India that are not very narrow-ribbed and
still bear the name H. davidus.

Surely both splitters and lumpers have tangled with this one before.
Have any of you had difficulty with this one?

Yours, Russell Renka

--
Russell D. Renka
Department of Political Science
Mail Stop 2920, Carnahan 211-L
Southeast Missouri State University
Cape Girardeau, MO 63701-4799
office:  573/651-2692
Home:  573/334-0039
FAX:  573/651-2695
URL:  http://cstl-cla.semo.edu/renka