Deep-throated Vertigo

The first discovery of Vertigo nylanderi, also known as the Deep-throated Vertigo, was discovered in the early 1900's along a stream off of the Caribou River in Minnesota by a man named Olaf Nylander. Victor Sterki would eventually name the snail after him in 1909. This species disappeared until the 1940's where it was found in both Southern Ontario and Northwestern Minnesota. Finally, in the Western Great Lakes region, the first live specimen was found in the late 1990's (Nekola 2008).

Vertigo - The genus
This genus consists of tiny snails with shells ranging from 1.5 to 3 mm in length and anywhere from 0-6 apertural lamellae when fully grown, most of which (approximately 2/3) are restricted to habitats only in North America. Until recently, the taxonomy was based almost entirely on shell characteristics like overall shape, surface sculpture, aperture shape and lamellar configuration because of a high degree of aphallism (lacking a penis) and reduction in male genitalia within the genus. Now, however, there is some DNA analysis of some species within the genus and there is evidence that Vertigo is indeed a monophyletic group. With so little testing and so few fossils (only two pre-Neogene Vertigo fossils have been found in North America and both are unlike any modern species), it is difficult to fully understand the diversification and history within the genus, leaving some contradicting ideas. For example, DNA evidence suggests Vertigo nylanderi resides on the same species-level branch as Vertigo arthuri but several unique morphological shell features leave people reluctant to accept this (Nekola, Coles, and Bergthorsson 2009).

If you want to learn about more snails in Wisconsin, take a look at Wisconsin Land Snails.

For an even more diverse array of organisms, check out Multiple Organisms!