Flat-spired Three-toothed Snail - Taxonomy

Taxonomy

Triodopsis platysayoides is now a formally-recognized species. It was first collected by Graham Netting at Coopers Rock, and later described by Stanley Brooks as Polygyra platysayoides from the area of Coopers Rock State Forest. The type specimen is stored in the collection of the Carnegie Museum of Natural History under number 62.23750.

The taxonomic status of T. platysayoides was subsequently questioned. In 1940 the American biologist Henry Augustus Pilsbry considered it to be a distinct species, and he also transferred it to the genus Triodopsis. However, based on rather limited information, Vagvolgyi classified Triodopsis platysayoides as merely a subspecies of Triodopsis complanata in 1968. This reclassification was not widely accepted however, and in 1974 Solem concluded that the available evidence did support full species status for this snail.

Triodopsis platysayoides was confirmed as a valid species with a unique penial morphology in 1988. Species status was also confirmed in 1988 by starch-gel electrophoresis of foot tissue, while examining evolutionary relationships among 40 species of tridopsine snails in eastern North America. Populations were divided into family trees showing the phylogenetic relationships among 18 groups of species. Nine of these groups consisted of a single species, of which Triodopsis platysayoides was one group.