Pyrgulopsis pachyta

Armored Marstonia

FWS Focus

Overview

Characteristics
Overview

The armored snail is a small hydrobiid snail, with relatively little known about its life history and ecology.  It is endemic to watersheds in northern Alabama.  In literature, the armored snail may also be referred to as armored marstonia and thick-shelled marstonia.

Garner, J. T. 2004.  Armored Marstonia, Pyrgulopsis pachyta (Thompson).  Page 122 in R. E. Mirarchi, J. T. Garner, M. F. Mettee, P. E. O’Neil, eds.  Alabama Wildlife.  Volume 2.  Imperiled Aquatic Mollusks and Fishes.  The Univeristy of Alabama Press, Tuscaloosa, Alabama.

Scientific Name

Pyrgulopsis pachyta
Common Name
armored marstonia
Armored snail
FWS Category
Snails
Kingdom

Location in Taxonomic Tree

Identification Numbers

TSN:

Characteristics

Characteristic category

Physical Characteristics

Characteristics
Size & Shape
  • The armored snail typically measures less than 4 millimeters (0.15 inches) in length.
  • It is typified by its shell’s ovate-conical shape and complete peristome (lip around the aperture of the shell).
  • The species is also characterized by its shell’s pronounced thickness.

Garner, J. T. 2004.  Armored Marstonia, Pyrgulopsis pachyta (Thompson).  Page 122 in R. E. Mirarchi, J. T. Garner, M. F. Mettee, P. E. O’Neil, eds.  Alabama Wildlife.  Volume 2.  Imperiled Aquatic Mollusks and Fishes.  The Univeristy of Alabama Press, Tuscaloosa, Alabama.

Thompson, F. G.  1977.  The Hydrobiid snail genus Marstonia.  Bulletin of the Florida State Museum, Biological Sciences 21:113-158.

Characteristic category

Life Cycle

Characteristics
Life Cycle

It has long been held that the armored snail has an annual life cycle like other similar species in its family.

Garner, J. T. 2004.  Armored Marstonia, Pyrgulopsis pachyta (Thompson).  Page 122 in R. E. Mirarchi, J. T. Garner, M. F. Mettee, P. E. O’Neil, eds.  Alabama Wildlife.  Volume 2.  Imperiled Aquatic Mollusks and Fishes.  The Univeristy of Alabama Press, Tuscaloosa, Alabama.

Characteristic category

Habitat

Characteristics
Habitat

The armored snail appears to be most common on submerged roots, leaves, and bryophytes along stream edges, submerged bryophytes growing on rocks in moderate current, and in water willow. They are also found in areas of slow to moderate flow in the submerged detritus, leaves, and tree rootlets along pool edges. The presence of armored snails is highly correlated with filamentous algae mats.

AST Environmental [AST].  2017.  2017 AST Environmental Annual Report Binder.  Report prepared for U.S. Fish and Wildlife Service.

Haggerty, T. M. and J. T. Garner.  2007.  Water quality investigation and status survey of the armored snail and slender campeloma in Limestone, Piney, and Round Island creeks, Alabama, year 1 report – qualitative survey and preliminary physicochemical analyses.  Report prepared for U.S. Fish and Wildlife Service, 17 pp.

Haggerty, T. M. and J. T. Garner.  2008.  Distribution of the armored snail (Marstonia pachyta) and slender campeloma (Campeloma decampi) in Limestone, Piney, and Round Island Creeks, Alabama.  Southeastern Naturalist 7:729-736.

Thompson, F. G.  1977.  The Hydrobiid snail genus Marstonia.  Bulletin of the Florida State Museum, Biological Sciences 21:113-158.

River or Stream

A natural body of running water.

Geography

Characteristics
Range
  • The armored snail was first documented in 1969 by Thompson (1977) in Limestone Creek, Limestone County, Alabama.
  • Later surveys extended its range to Little Limestone, Piney, Little Piney, and French Mill creeks, but it is believed that the Limestone and Piney Creek watersheds are the extent of its range.

Haggerty, T. M. and J. T. Garner.  2008.  Distribution of the armored snail (Marstonia pachyta) and slender campeloma (Campeloma decampi) in Limestone, Piney, and Round Island Creeks, Alabama.  Southeastern Naturalist 7:729-736.

Thompson, F. G.  1977.  The Hydrobiid snail genus Marstonia.  Bulletin of the Florida State Museum, Biological Sciences 21:113-158.