Truncatellina cylindrica alive, and gigantic, in Scotland

In the Conchologists’ Newsletter no. 152 (March 2000) I reported the finding, in November 1999, of Truncatellina cylindrica at Dumbarnie Links Wildlife Reserve (Scottish Wildlife Trust) in Fife (N0 440022). At that time only empty but fresh shells had been found. Since then many more similar shells have been found throughout the seven hectare site, making 114 in all, but also seven live individuals between January 2001 and November 2009. All the live ones were at one location, in grass divots at the base of a concrete WW2 pill-box. Searching by myself and others has failed to find it at its only known 20th century site in Scotland, on Arthur’s Seat in Edinburgh in the 1930s.

In December 2009 a remarkable empty but fresh shell was found by sieving sand on the reserve – similar in diameter to the others but 2.7 mm high. A sample of 67 others from the reserve measured 1.50 to 1.95 mm (median 1.80), with a single one 2.20 mm. Apart from the height, with two additional whorls, the giant closely resembles normal specimens. The photograph (right) shows the giant along with a normal one 1.8 mm in height. Are there any precedents in this or related species?