Dear Mr Renka , since the width of the ribs of a Harpa specimen can vary a
lot  this feature cannot be  a criterion  to tell a Harpa species from
another  .  H. major 's distribution  range includes that of H. davidis (
not "davidus " ) ; moreover H. major and H. davidis are sympatric inside the
distribution range of  H. davidis , here are arguments in favor of their
separation at the specific level .However only an close anatomical study of
preserved animals could confirm that  since the protoconchs of  H. major and
H. davidis are almost identical . So  the
only feature which  readily distinguishes them is the number of ventral
blotches : H.
davidis always has three separate blotches  when H. major can have one or
two .  In my collection I have  a H. major from Vanuatu and a H. davidis
from the Gulf of Bengal which are identical except for the number of ventral
blotches ...According to me for the time being  the best solution is to give
the name H. davidis to the Harpa specimens with three ventral blotches from
the Gulf of Bengal till we know more about their exact status . Franck
Frydman
----- 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
>