Buffalo Pebblesnail

Gillia altilis (I. Lea, 1841)

Gillia altilis shell
David Bullis

Gastropoda (Gastropods)
State Protection
Special Concern
Listed as Special Concern by New York State: at risk of becoming Threatened; not listed as Endangered or Threatened, but concern exists for its continued welfare in New York; NYS DEC may promulgate regulations as to the taking, importation, transportation, or possession as it deems necessary.
Federal Protection
Not Listed
State Conservation Status Rank
Critically Imperiled in New York - Especially vulnerable to disappearing from New York due to extreme rarity or other factors; typically 5 or fewer populations or locations in New York, very few individuals, very restricted range, very few remaining acres (or miles of stream), and/or very steep declines.
Global Conservation Status Rank
Secure globally - Common in the world; widespread and abundant (but may be rare in some parts of its range).


Did you know?

The Buffalo Pebblesnail was able to extend its range westward through the Erie Canal to establish populations in waterbodies it was not native to.

State Ranking Justification

No populations were located during Strayer's 1987 survey or Jokinen's surveys of 1978-1991.

Short-term Trends

The short-term trends for this species are unknown but the population appears to be declining. The last known records of Buffalo Pebblesnails in the Hudson River are from 1936 (Coote 2015). However, lack of records could be due to a lack of survey work or incomplete surveys, or possibly due to a misidentification of specimens.

Long-term Trends

The long-term trends for this species are unknown, although it appears to be declining. This was once considered a common and widely distributed species in New York (Baker 1916) and has not been found in more recent surveys from previously known locations.

Conservation and Management


Threats to this species are difficult to determine due to a lack of information on its current habitats, status, and trends. However, freshwater gastropods are generally impacted negatively by habitat fragmentation, alteration, or destruction from dams, impoundments, riparian development or degradation, groundwater withdrawal, and other similar impacts to their freshwater environment (NYS DEC 2014)

Conservation Strategies and Management Practices

Conservation strategies and management practices are difficult to determine without more current information on status and habitat requirements of the Buffalo Pebblesnail. However, these snails would probably benefit from general management practices that apply to freshwater gastropods. These include prevention of habitat degradation from pollution, dams or impoundments, or development. Any activity that causes drastic water fluctuations can also lead to snail population declines (NYS DEC 2014).

Research Needs

Additional research and ongoing monitoring are needed for this species (Coote 2015). Survey work to determine the actual current range and habitats of this snail would give us a better idea of habitat requirements, population trends, threats, and conservation strategies (NYS DEC 2014).



The Buffalo Pebblesnail has been known to occur in several different habitat types, ranging from stagnant lakes to fast flowing rivers. It has been found in freshwater streams and rivers, including on mud and aquatic plants in freshwater tidal Hudson River (Strayer 1987, Jokinen 1992). This snail has also been found on the sandy bottom of shallow lake waters including open and partially open bays (Baker 1916). Eggs are laid on the leaves and stems of aquatic plants (Thompson 1984).


New York State Distribution

This species was not originally in the Lake Ontario system, but was able to move west through the Erie Canal (Jokinen 1992). Historically Gilia altilis was found in the Hudson River in Albany, Dutchess, and Ulster counties. Museum records also show this species has been found in the Erie Canal in Herkimer and Onondaga Counties, the Champlain Canal in Rensselaer County, as well as Niagara, Monroe, and Wayne Counties (Jokinen 1992). There is evidence of Buffalo Pebblesnails from Lake Ontario, Oneida Lake, and the Salmon River as well.

Global Distribution

The Buffalo Pebblesnail inhabits the Atlantic coastal drainage systems from New York and Vermont west to Lake Ontario and south to South Carolina (Jokinen 1992).

Best Places to See

  • (Herkimer, Monroe, Onondaga, Oswego Counties)

Identification Comments

Identifying Characteristics

Many species of the Lithoglyphidae and Hydrobiidae families are visually similar, and many require dissection to ID to the species level. Therefore, the Buffalo Pebblesnail can be difficult to identify. The top of the body, tentacle, and the mantle are mostly black, while the sides of foot and snout are light gray and the underside of the tentacles is white (Thompson 1984). The shell is a light yellow-green, conico-globose with a convex body whorl, and is relatively large (6-8 mm) (Jokinen 1992). The protoconch has fine spiral threads. This species also has a radula that differs from similar species; the central and lateral teeth are modified to feed on coarser food particles, and the cusps on the teeth align to form a single blade that is large and serrate (Thompson 1984). Buffalo Pebblesnails have a similar radula structure to F. nuttalliana. However, the inner marginal tooth of Buffalo Pebblesnails has approximately 30 cusps and the outer marginal tooth has approximately 6 to 9 stout cusps while F. nuttalliana has about 16 acuminate cusps on the inner marginal tooth and 12 or 13 cusps on the outer marginal tooth. The reproductive systems of both males and females also from other similar species.

Best Life Stage for Proper Identification


  • Present

The time of year you would expect to find Buffalo Pebblesnail present in New York.

Buffalo Pebblesnail Images


Buffalo Pebblesnail
Gillia altilis (I. Lea, 1841)

  • Kingdom Animalia
    • Phylum Mollusca (Mollusks)
      • Class Gastropoda (Gastropods)
        • Order Littorinimorpha
          • Family Lithoglyphidae

Additional Resources


Baker, Frank C. 1916. Technical Publication 4: The relation of mollusks to fish in Oneida Lake. The New York State College of Forestry at Syracuse University, Syracuse, NY. Volume 16:21.

Coote, T. W. 2015. New gastropod records for the Hudson River, New York. American Malacological Bulletin 33(1):114-117.

Jokinen, E.H. 1992. The Freshwater Snails (Mollusca: Gastropoda) of New York State. New York State Museum, Bulletin, 482: 1-112.

New York Department of Environmental Conservation. 2014. Species Status Assessment of Gillia altilis.

New York Natural Heritage Program. 2023. New York Natural Heritage Program Databases. Albany, NY.

Strayer, David L. 1987. Ecology and zoogeography of the freshwater mollusks of the Hudson River basin. Malacological Review 20:1-68.

Thompson, F.G. 1984. North American freshwater snail genera of the hydrobiid subfamily Lithoglyphinae. Malacologia, 25(1): 109-142.


About This Guide

This guide was authored by: Ashley Ballou

Information for this guide was last updated on: July 13, 2021

Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Gillia altilis. Available from: https://guides.nynhp.org/buffalo-pebblesnail/. Accessed December 8, 2023.