Dear Guido,
Is it your experience that seperate, distinct populations of C. cucumis and
C. cymbium have been found to exist at the same local? Do intergrades
represent interbreeding or just an overlap of the natural variation of two
morphologically similar species?
Scott Jordan
-----Original Message-----
From: Guido Poppe <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Friday, June 18, 1999 12:38 AM
Subject: Re: Cymbium
>>Scott E Jordan wrote:
>>>
>>> Is there a reliable way to differentiate Cymbium cucumis Roeding, 1798
>>> from Cymbium cymbium, L., based solely on shell morphology? I can't
>>> tell looking at Poppe and Goto.
>>>
>>> Regards,
>>>
>>> Scott Jordan
>>T.E Eichhorst's answer is complete. Note that in most specimens
>>C.cucumis have three columellar plaits and a rusty color, C.cymbium only
>>two and a greyish color.We can also observe that Poppe & Goto pictures
>>show likely two specimens of the same species: C.cucumis!
>>In this genus, we have many transitional forms, the limits of
>>specification is not always defined and a deep Revision is needed.
>>Regards, Pat
>
>I'm sorry that I've to react, but figures 5 & 6 are definitely C. cymbium,
>they came from a lot of C. cymbium, but the choice of the specimen is not
>good for that type of book. Indeed, the C. cucumis, nr. 4 is also not well
>chosen. Most cucumis from nature resemble the cymbium in this book, and
>most cymbium resemble the cucumis nr. 4. (apart for the colour that is
>correct)
>As Pat points out, there are many transitional forms, and the ones shown do
>not clearly demonstrate the characteristics of both.
>One has also to say that these are not easy shells, but I'm sure that if
>one is playing a week with half a thousand Cymbium, things become clear int
>he mind. Not so clear as between Cypraea talpa and Cypraea tigris, but well
>defined. As with Clausilia (Joke)
>
>Guido
>
>Visit Conchology, with over 50000 names with author, 3800 indicated type
>species, 5000 conchological images, and fun with shells.
>http://www.conchology.uunethost.be/
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>http://www.conchology.uunethost.be/go/iconography/index.html
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