Batillaria minima in a tide pool at Spittal Pond, Bermuda

 

Batillaria minima is a tiny snail found in the Caribbean, from Bermuda to Florida to the Bahamas. They grow to a maximum size of about 15 mm. Their shell is an elongated conical shape with beaded ribs and uneven spiral threads (Sterrer 1986). They have a narrow aperture. Their bodies (inside the shell) are all black. The shells of Batillaria minima come in color morphs of off-white to gray to all black. Almost all the B. minima I found in the tide pool at Spittal pond were of the all black variety, with some white banding. Batillaria minima is the only species in Bermuda representing the Potamididae family. This family is characterized by the lack of denticles (small tooth-like grooves) on the outer lip as well as their lack of a penis (Sterrer 1986).

Spittal Pond is a brackish pond in Bermuda, the site of a nature reserve and bird sanctuary. It is located on the Southeast shore of the island. It is one of the few places to access a rocky shoreline. It is here where I found a large tide pool at a height that the tide doesn’t reach very often. But the tide pool is large enough that it can retain a good deal of water between tides. I would estimate it to be about 6 m in diameter with ankle-deep water. The tide pool was home to a couple thousand tiny snails (Batillaria minima) and a couple dozen hermit crabs hiding out in the shells of dead Batillaria. (Melinda Hewitt has drawn a very nice map of Bermuda that shows Spittal Pond's location.)

The most interesting thing about the snails in the tide pool at Spittal Pond was their strange dispersal pattern. They all appeared to be clustering under and around the small, loose rocks in the tide pool.

 

Also, visit the Bermuda Biological Station for Research, where we stayed in Bermuda, to learn more about marine and ecological research in Bermuda.

© 2002 Laura Brentner, for educational purposes only


Close up of Batillaria minima color morphs

 

Tide pool at Spittal Pond (the tiny black specks are the snails)

 

Batillaria minima clustering around rocks in the tide pool

My Experiment
Gastropod movement:: other studies and mine

     More Background on Batillaria

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