Harpa davidis is indeed told to have narrow ribs, but in my collection
(about 20 davidis), it also ranges from very narrow to rather broad.  The
ventral pattern might be a help (very broad pale wing in davidis, as opposed
to almost no wing in major). But again, you will be able to find
intermediate specimens. It's best to look at the protoconch and the top: you
can see images of tops in Poppe's Iconography.
Moreover, although H. davidis is mentioned to come from the P.I., I have
never seen one (I've bought one several times, but it's always major). The
only 'true' localities I know are India and Sri Lanka. I tried to buy some
from Vietnam, but again, it was all H. major.

Best regards,

David
----- Original Message -----
From: Russell Renka <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, May 31, 2001 6:31 PM
Subject: Harpa major v. Harpa davidus


> 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
>