Dear Jan,

Thanks for sending this on to me. I guess it means that there's a consensus
that spiral sculpture is present on M. groenlandicus. I wonder if there's
some authoritative recent discussion to refute Rehder's contentions. It is
confusing.

Thanks again,
David


----------
>From: Jan Haspeslagh <[log in to unmask]>
>To: [log in to unmask]
>Subject: Re: Happy Hour with Margarites
>Date: Wed, Sep 27, 2000, 6:36 PM
>

>Hi David,
>
>Maybe you are familiar with Poppe & Goto's work : European Seashells,
>vol 1 ? If not, here's the section on the Margarites groenlandicus
>(hopefully not to add to your confusion):
>
>---------------------------------------------------------------------------
----------
>--------------------------
>
>Margarites groenlandicus (Gmelin, 1791)
>A circumboral species. In Europe it lives from northern Scandinavia
>south to Scotland...
>5 to 10 mm
>... colour goes from green to pink and orange. In Europe the species has
>heavy spiral ridges all over the shell. Specimens from Greenland are
>usually smooth. Flattened shells with a closely set spiral sculpture are
>called form undulata Sowerby, 1838.
>
>---------------------------------------------------------------------------
----------
>---------------------------
>
>Maybe this will help you further on. Looking at the photo in Poppe &
>Goto, added to their description and your description, I'm pretty sure
>you will have a groenlandicus.
>
>Best regards,
>
>Jan Haspeslagh
>Belgium
>
>David Kirsh wrote:
>>
>> Dear all,
>>
>> I just received a couple of Margarites from Iceland in trade. I see
>> that identification is not entirely straight forward.
>>
>> One is 7.5mm in diameter and has seven spiral ridges on the top of the
>> body whorl ( on magnification, the ridges look like waves of fudge)
>> and a dozen low smooth spirals on the base. My trade-mate calls it M.
>> groenlandicus.
>>
>> However, in Abbott's Am. Seashells (2nd ed.), groenlandicus Gmelin is
>> smooth on the base and has "about a dozen spiral lirations" on the top
>> (an almost entirely smooth form is called umbilicalis Broderip and
>> Sowerby) . Abbott's Seashells (1991, covering northern North Atlantic
>> and northeastern Pacific) says groenlandicus' base is smooth and top
>> of whorls "glassy smooth." So far, this is not a very comfortable fit.
>>
>> OK, when I looked in Rehder's National Audubon Society Field Guide to
>> N. American Seashells, there was a nice resolution (not necessarily
>> correct). Rehder describes M. striatus: "....body whorl with low,
>> obscure, distant, wavelike ridges below the suture. Base with lower
>> and broader spiral threads...." He also contends that M. groenlandicus
>> "however, is smooth and found only in northern Greenland and some of
>> the Arctic islands."
>>
>> I have a feeling this has been a very thorny tangle in the literature.
>> Is there any better consensus lately?
>>
>> David Kirsh
>> Durham, NC