| Spiny river snail | |
|---|---|
| A live individual of Io fluvialis | |
| A live individual of Io fluvialis | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| (unranked): | clade Caenogastropoda clade Sorbeoconcha |
| Superfamily: | Cerithioidea |
| Family: | Pleuroceridae |
| Subfamily: | Pleurocerinae |
| Genus: | Io Lea, 1831[2] |
| Species: | I. fluvialis |
| Binomial name | |
| Io fluvialis (Say, 1825) |
|
The spiny river snail, scientific name Io fluvialis, is a species of freshwater snail, an aquatic mollusk in the family Pleuroceridae. The only species in the genus Io,[3] it has served as the emblem for the American Malacological Society since 1960.[4]
This species is endemic to the Tennessee River and its larger tributaries, but has been largely extirpated due to pollution and the construction of dams. They live in rapidly flowing well oxygenated waters of shoals and riffles of rivers, but not in slack water below shoals. Preferred water depth is up to 1.5 m., where they feed on the algal coating on rocks. Females lay between 20-100 eggs, which begin to hatch after 15 days.
The shell morphology is variable, with some individuals totally lacking spines. For this reason it was formerly thought that many species existed.