16 July 2012

Discus rotundatus in Montreal


Dcatskillensis1

In August 2008, I announced here my finding of the snail Discus catskillensis on Mont Royal in Montreal, Canada*. Subsequently, a few readers questioned my identification and suggested that the snail I had found was more likely the European species D. rotundatus. While the former species is a native of North America, the latter was introduced to the eastern U.S. early in the 20th century and later to Canada.

For a more definite identification, I needed more specimens. But I did not have a chance to go back to Mont Royal until August 2011 when I was able to collect a few more shells. Last fall, I compared the Montreal specimens with the shells of several Discus species. The results indicated that the Montreal species was indeed D. rotundatus.

The final outcome of this project was a short paper that recently got published in Check List. You may download a copy of it from here.

*I have now deleted the original post of 2008. Attempting to revise it would have been too much trouble.

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