Early last week, a reader e-mailed the picture of a snail shell he had found in Maryland and asked for an identification. To my surprise, it turned out to be Cepaea nemoralis, a native of Europe introduced to a few places in the U.S. Subsequently, I got from the reader the GPS coordinates and detailed directions to his collection spot along with the warning that there was a lot of poison ivy in the area.
The location turned out to be only about a half an hour drive from where I live. So this morning I took my son along and went there. The exact spot was surrounded by an impenetrable wall of poison ivy. While I was scouting the area and trying to figure out what to do, my 14-year old son, who has been trained since the age of 4 to spot snail shells, announced his first find. It was indeed an empty Cepaea nemoralis shell from the edge of the busy highway next to us. Empty shells turned out to be quite abundant among the grass along the metal guardrail separating us from the highway. Soon we had close to 40 shells.
Here is our collection spot.
The live snails took longer to find. Eventually, I spotted them on damp soil inside the cavities around the bases of the guardrail posts.
Its brown lip distinguishes Cepaea nemoralis from the similar Cepaea hortensis. The latter, known from some islands off the coast of northeast U.S., may or may not be native to North America.
I have no idea how and when these snails were introduced to this spot. We will probably write a short paper to publish this new record for Maryland. Until then, I will keep the exact location confidential.