Following along the lines of my recent posts on miniaturization of animals (here and here), I am putting up these pictures of a tiny snail, Vertigo gouldi, an endemic of North America. The shell of this particular adult individual was 1.6 mm long.
This species was named by Amos Binney in 1843 after Augustus A. Gould (1805-1866), an early American malacologist. Binney’s drawing from his 1857 classic the Terrestrial Air-breathing Mollusks of the United States is on the right. As you can also see in the photograph below, the shell is covered by fine striae, a characteristic that helps distinguish this species from other closely related ones.
The genus Vertigo is in the family Vertiginidae (or the Pupillidae, depending on who you believe). One notable characteristic of this genus and a few other related genera is that the snails have only one pair of tentacles. All other pulmonate land snails that carry their eyes on the tips of their tentacles (order Stylommatophora) have two pairs of tentacles, one longer upper pair and a shorter lower pair. The Vertiginidae lack the latter pair as you can see in the photograph of the live snail.
Both photographs of Vertigo gouldi were taken with an Olympus Camedia C-5000 digital camera through an Olympus SZ60 stereomicroscope.