Evolution of Inflectarius

It is generally accepted that the land pulmonates were derived from freshwater ancestors following the usual pattern of marine to freshwater to land. It was first believed that the family Ellobiidae was close ancestors to the early developing snails (Trueman, 1985). Ellobiids appeared later in the fossil record while the first land snails are from the Carboniferous of eastern North America from around 150 million years ago. In fact, some of the early land snails were believed to be classified in the Ellobiidae but as more research was done, this was proven to be untrue (Trueman, 1985). From this, the land snails became to be identified as stylommatophoran pulmonates.

Photo taken by John Slapcinsky of an Inflectarius snail

The family Polygyridae is indigenous to North America with approximately 260 species
(Malacologia, 1998).  A subfamily of Polygyridae has been known as Mesodon. It took a while for the name Mesodon to be recognized. At first, it was only identified as a genus of one species. Eventually, it became to be recognized as all eastern North American land snails with capacious shells that are capable of containing more space and a small parietal tooth or toothless. It was Pilsbry’s experiments in 1939 that led to the use of the genus Mesodon. Pilsbry then divided the genus into four subgenera:  Mesodon, Patera, Appalachina, and Inflectarius (Malacologia,1998). Pilsbry based it upon their shell shape.

To learn more about what Inflectarius rugeli looks like, click HERE