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MARGINALIA

The Rarest Snail in the World

Do development and scientific study conflict with conservation?

Pat Shipman

Into the Thicket

2011-11MargShipmanFB.jpgClick to Enlarge ImageWe set out one morning, equipped with plastic bags, brushes, a sieve, sunscreen, a camera and a flask of water, to look for snails. We hiked to a habitat we thought sounded right: an area off one of the main roads where there had once been a historic house belonging to Captain Woody. The captain was a remarkable man who had cleared, by hand, the original airstrip on Little Cayman in the 1960s. The area where his house had stood was fairly open, with lots of exposed limestone bedrock and thickets of small trees and shrubs with sparse undergrowth.

After roughly 15 minutes of scouring the ground and picking up snails that were not C. nanus, my husband cried “Got it!” He’d found an empty C. nanus shell among many more C. pannosum shells. Whereas the C. pannosum shell is about the size of a large plump peanut and is white—sometimes with brown highlights on its rough surface—the C. nanus shells are only half as long and rather svelte, not as thick as a pencil. They are mostly grayish or white. Once we had finally seen a dwarf shell ourselves, we quickly found more. We went home that day with about a dozen dead specimens. We were very proud of our success in our first venture into malacology.

But where was the Evolvulus bush? Or rather, which was the bush? None of the plants near the dead shells fit the description. Many had grayish leaves and pungent odors when crushed, as do many plants in dry habitats. But most were taller than half a meter. None had any C. nanus shells clinging to them. Eventually we discovered that the heathlike bush with scalelike leaves looked like a tangle of dead twigs because we were searching during the dry season. Everything living in such a seasonal habitat must adapt to dramatic changes in moisture, and Evolvulus did so by dropping its leaves and dying back.

In the days that followed, we corresponded by e-mail with Mike, obtained more information online about our quarry, and spent a few more hours searching for snails. Checking former paths and likely habitats, we found dead dwarf Cerion intermingled with the larger live and dead Cerion and other snails. We hacked and squirmed our way through overgrown trails, so thick we could not see each other if we were more than 3 or 4 meters apart. But if we could see any Evolvulus plants, we checked the area out. We found those habitats to be scratchy, mosquito-ridden and mostly snail-free.





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