Marstonia scalariformis explained

Marstonia scalariformis, previously known as Pyrgulopsis scalariformis, common name the moss pyrg, is a species of freshwater snail in the family Hydrobiidae.

Shell description

The shell is high with 5.5–6 whorls. The shell is turreted, slender, and chalky white in color. The suture is deeply impressed. The shell is carinate in its entire length on the lower edge of the whorls.

The aperture is small, ovate, but slightly connected with the last whorl.

Anatomy

The body of the animal is white.^[1]

Distribution

Distribution of Marstonia scalariformis include Illinois,^[2] Alabama,^[3] Iowa, and Missouri, all within the Mississippi River System. Alive specimens are only known from Alabama and Missouri.

This species was abundant on its type locality on the Tazewell shore of the Illinois River in 1880s.

Conservation

This species is critically imperiled.^[4]

Notes and References

1. Hershler . R. . 1994 . A review of the North American freshwater snail genus Pyrgulopsis (Hydrobiidae) . . 554 . 554. 1–115 . 10.5479/si.00810282.554 . free . 10088/5139 .
2. Web site: Freshwater snails of Illinois . Illinois Natural History Survey Mollusk Collection . Illinois Natural History Survey . 16 August 2024 .
3. Web site: Alabama Inventory List. The Rare, Threatened, & Endangered Plants & Animals of Alabama . November 2020 . Alabama Natural Heritage Program . 16 August 2024 .
4. Web site: Marstonia scalariformis Moss Pyrg . NatureServe Explorer . 20 October 2008 . NatureServe . 16 August 2024 .