24 March 2011

Eobania vermiculata gets bigger

As explained in yesterday's post, I am busy measuring shells of the land snail Eobania vermiculata. Actually, I spend only about a half an hour a day doing that, measuring 8 to 10 shells at each session.

Among the shells I measured tonight, there was a nice surprise. One of the only 3 shells collected at one locality turned out to be the largest Eobania shell I have measured so far. Its diameter, 34.8 mm, is almost the same as the maximum of 35 mm George Tryon gave in the Manual of Conchology (vol. 4, 1888). Who knows how accurate Tryon's measurements were anyway.

The current record holder is the leftmost shell in the picture below (unfortunately, it has a large hole in its spire).


Interestingly, the middle shell in the picture is the 15th smallest shell among the total of 96 shells I have measured. So here we have 2 shells from one locality representing each end of our distribution.

Expect more on this topic.

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