The Fargo Worm Snail, Vermicularia fargoi Olsson, 1951, is a gastropod with a shell that starts regularly coiled until it is about an inch long. From then on, the shell then becomes uncoiled, acquiring its typical, irregular shape. The shell “tube” is about 3/8” in diameter. Shells of the Fargo Worm Snail are fairly common along the beaches of Southwest Florida, and so are those of a close living relative previously portrayed in this column, the Florida Worm Snail, Vermicularia knorrii (Deshayes, 1843). Both Fargo and Florida worm snails do not form large clusters, but Vermicularia recta Olsson & Harbison, 1953, a Florida Pliocene fossil (between 2.5 and 5 million years of age), is a gregarious species, forming very large and dense beds, with its uncoiled shells reaching 10” in length.
The photos show, from Left: Shells of Fargo Worm Snail, Vermicularia fargoi, (about 1.5” and 2.5” in length) and its Florida Pliocene fossil relative, Vermicularia recta (cluster about 15” in width) Photos by José H. Leal.