17 April 2011

Many more Neohelix

A couple of weeks ago, I found a location not too far from my house where there were shells of the land snail Neohelix albolabris. The posts about the 2 casual collections I did at that spot are here and here.

Late Friday afternoon for almost an hour, my wife and I did a more careful search for shells in the location. Not only did we find more empty shells, but also 5 live adult Neohelix. There is certainly an extant colony there.

We only took the empty shells. There are now 22 measurable adults, just about enough to constitute a statistically meaningful sample. Experienced readers may spot a few Mesodon thyroidus shells also in the lot. I have often found the 2 species together; they don't seem to mind each other's company.

One of the shells had a low parietal tooth in its aperture (red arrow in the picture below). As I noted in this old post, the presence or the absence of this tooth is an example of intraspecific variation in this species.

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