Shells from Eleuthera, Bahamas

Eleuthera is a unique island for shells, in that it has several salt ponds that have only deep underwater outlets to the sea. Therefore, they are tidal, but only a few species of shells, fish and crabs live in them. Some of these animals appear to have evolved in their isolation into "new" species, differing from the original enough to be distinctive.

Two of these ponds are Sweetings Pond and the Great Oyster Pond, also known as the Blue Hole and, to the natives, the Unique, because it is across the road from the Unique Hardware store. The Great Oyster Pond has many smallish pearl oysters which attach to the several unique algaes that live in the pond and give it an eerie appearance.
 

Two of the possibly three species of ophistobranchs called commonly "bubble shells" found in the Great Oyster Pond. On the left is a Bulla species, probably Bulla striata and on the left a Haminoea species. These animals are too large for their shells and have a large, spatulate foot which is useful for burrowing in sand. They also give out quantities of slime, which helps them move under the sand.

 
Prunum species

This is also from the Great Oyster Pond and is either a form of Prunum apicinum or a new species.

 
Fasciolaria tulipa, "True Tulip"

These, together with Chicoreus dunni make up the only predator mollusks in the Great Oyster Pond. They are also found in Sweetings Pond. They never grow to large size in this calcium-deficient environment, and are often thin shelled and whitish in color.

 
Chicoreus dunni

This is one of three species that so far has been recognized as "new" from the ponds. It evolved from Chicoreus florifer, a common shell in open water in Eleuthera.

 
Volvarina species

One of at least three "new" marginellas found in Sweetings Pond, this is the most common. I hope overcollecting, now that the location of the pond is known, does not decimate the population.

 

Another unidentified marginella from Sweetings Pond.

 

The third unidentified marginella from Sweetings Pond that I know of.

 

Eleuthera also has an abundance of land and tree snails. I have not tried to identify this one, which was crawling on the wall at my hotel.