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''Gillia altilis'',
common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...
the Buffalo pebblesnail, is a
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of
freshwater snail Freshwater snails are gastropod mollusks that live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs t ...
, an aquatic
gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...
mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000  extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...
with an operculum in the family Lithoglyphidae.Thompson F. G. (1984). "North American freshwater snail genera of the hydrobiid subfamily Lithoglyphinae". ''
Malacologia ''Malacologia'' is a peer-reviewed scientific journal in the field of malacology, the study of mollusks. The journal publishes articles in the fields of molluscan systematics, ecology, population ecology, genetics, molecular genetics, evolution, an ...
'' 25(1)
109
141.
''Gillia altilis'' is the only species in the genus ''Gillia''.


Shell description

The
shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ...
of this species is inflated but still conical. The shell color is usually yellow to green. The shell has 2–4 whorls when eroded, and ~4.5 when intact. Each whorl is distinctly shouldered. The umbilicus is either not apparent, or very small. The
columella Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire. His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...
is not thickened, and the shell itself can be thin or thick. The shell
aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...
is oval to ear-shaped. When viewed laterally, the outer lip of the shell bends forward. The height of the shell is 6–8 mm (– in). The operculum is
chitin Chitin (carbon, C8hydrogen, H13oxygen, O5nitrogen, N)n ( ) is a long-chain polymer of N-Acetylglucosamine, ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cell ...
ous, oval, yellow to green in color and shows paucispiral markings, with a subcentral nucleus.


Anatomy

The mantle is black, or shows dark pigmentation. This pigmentation is also seen in the nape, the anterior part of the
snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, Rostrum (anatomy), rostrum, beak or proboscis. The wet furless surface around the nostrils of the n ...
, the top of the
tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...
s, and along the edge of the
peristome Peristome (from the Greek language, Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mo ...
(the margin of the gastropod shell). The
radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...
of ''Gillia altilis'' looks like a single serrated blade, with 51-55 rows of teeth. Each row has 2 central basocones, 3-4 central octocones, 8-9 lateral teeth, ca. 30 inner marginal teeth and 6-9 outer marginal teeth.


Distribution


Indigenous distribution

''Gillia altilis'' is native to the
Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...
coastal drainage of
North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
.Mills E. L., Leach J. H., Carlton J. T. & Secor C. L. (1993). "Exotic species in the Great Lakes: a history of biotic crises and anthropogenic introductions". '' Journal of Great Lakes Research'' 19(1):1-54. It occurs from
New York State New York, also called New York State, is a state in the northeastern United States. Bordered by New England to the east, Canada to the north, and Pennsylvania and New Jersey to the south, its territory extends into both the Atlantic Ocean and ...
and
Vermont Vermont () is a U.S. state, state in the New England region of the Northeastern United States. It borders Massachusetts to the south, New Hampshire to the east, New York (state), New York to the west, and the Provinces and territories of Ca ...
south to
South Carolina South Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders North Carolina to the north and northeast, the Atlantic Ocean to the southeast, and Georgia (U.S. state), Georg ...
. In some regions where ''Gillia altilis'' is native, populations are declining or not very abundant: for example, in Vermont, this species is considered to be an invertebrate species in "greatest conservation need". This snail is listed as a species of special concern in its native range in New York State, where the species is ranked as S1 (very vulnerable due to low abundance of species and/or required habitat), protected U SC (unprotected at present but of special concern due to increasing evidence of vulnerability) and globally as G5 (rare but not vulnerable).
Loss of habitat Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...
due to anthropogenic modifications, pesticides and competition with introduced species are considered the major threats to declining or vulnerable gastropod populations in New York State.


Nonindigenous distribution

The first record of ''Gillia altilis'' in the
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...
drainage was from Oneida Lake, New York State, around 1915–1918. However, in subsequent years it was likely extirpated from this water body. ''Gillia altilis'' was able to colonize the
Lake Ontario Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York (state), New York. The Canada–United Sta ...
drainage basin by means of the
Erie Canal The Erie Canal is a historic canal in upstate New York that runs east–west between the Hudson River and Lake Erie. Completed in 1825, the canal was the first navigability, navigable waterway connecting the Atlantic Ocean to the Great Lakes, ...
system in New York State, which connects this part of the Great Lakes with the
Hudson River The Hudson River, historically the North River, is a river that flows from north to south largely through eastern New York (state), New York state. It originates in the Adirondack Mountains at Henderson Lake (New York), Henderson Lake in the ...
. The snail was later recorded from
Niagara-on-the-Lake Niagara-on-the-Lake is a town in Ontario, Canada. It is located on the Niagara Peninsula at the point where the Niagara River meets Lake Ontario, across the river from New York (state), New York, United States. Niagara-on-the-Lake is in the R ...
,
Lake Ontario Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York (state), New York. The Canada–United Sta ...
, in 1936, and in the
Erie Canal The Erie Canal is a historic canal in upstate New York that runs east–west between the Hudson River and Lake Erie. Completed in 1825, the canal was the first navigability, navigable waterway connecting the Atlantic Ocean to the Great Lakes, ...
at various times before 1940. ''Gillia altilis'' is considered established in the Lake Ontario drainage. The
New York State Department of Environmental Conservation The New York State Department of Environmental Conservation (informally referred to as NYSDEC, DEC, EnCon or NYSENCON) is a department of New York state government. The department guides and regulates the conservation, improvement, and protecti ...
also reports records from
Lake Erie Lake Erie ( ) is the fourth-largest lake by surface area of the five Great Lakes in North America and the eleventh-largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and also has the shortest avera ...
, but gives no references and declares that the current status of this population is unknown.New York State Department of Environmental Conservation, in cooperation with Cazenovia College and the Riverhead Foundation for Marine Research. (2005). ''New York State Comprehensive Wildlife Conservation Strategy''. Appendix A8: Comprehensive Wildlife Conservation Strategy Species Group Reports for Mollusks. 53 pp. At this time, there are no recorded negative impacts in the Great Lakes system. There are also no known impacts in other water bodies at present.


Ecology


Habitat

''Gillia altilis'' is usually found in
freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...
stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...
environments. Its globose shell is adapted for inhabiting high-velocity lotic environments ( rheophile animal), because it allows for a large, muscular foot that can suction to rocks. However, relatives of this species, with the same globose shell and large foot, are well adapted to living on silty substrates because the large foot prevents the snail from sinking. In fact, it is not uncommon for ''Gillia altilis'' to inhabit both stagnant waters in lakes and streams and rapidly moving waters. In Vermont, it is found in the
Hudson River The Hudson River, historically the North River, is a river that flows from north to south largely through eastern New York (state), New York state. It originates in the Adirondack Mountains at Henderson Lake (New York), Henderson Lake in the ...
in shoals where there is macrophyte cover and mud substrate.Kart J., Regan R., Darling S. R., Alexander C., Cox K., Ferguson M., Parren S., Royar K., Popp B. (eds.) (2005). ''Conservation summaries for species of greatest conservation needs. Invertebrate SGCN list.'' In Vermont’s Wildlife Action Plan.Vermont Fish and Wildlife Department, Waterbury, Vermont. Appendix A3. In New York State, it also commonly inhabits warmwater, shallow lacustrine habitats with mud substrate.


Feeding habits

This snail has a
radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...
that is specialized, exhibiting overall larger but fewer cones and cusps on the various teeth, which are adapted for grazing on coarser food particles than are eaten by related snails in the subfamily Lithoglyphinae.


Life cycle

''Gillia altilis'' exhibits separate sexes. Sperm is transmitted to the female through a penis that extends from the nape of the male. This species lays its eggs in hemisphere-shaped capsules, singly or in clumps up to six at a time, on leaves and stems of macrophytes (or stones and leaf litter). The egg capsules are ~1.25 mm in diameter.Jokinen E. (1992). ''The Freshwater Snails (Mollusca: Gastropoda) of New York State''. The University of the State of New York, The State Education Department, The New York State Museum, Albany, New York 12230. 112 pp.


References

This article incorporates public domain text from the referenceKipp R. M. & Benson A. (2008). "''Gillia altilis''".
USGS The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...
Nonindigenous Aquatic Species Database, Gainesville, FL. Revision Date: 2/25/2007.


External links

* Jennifer Price
Buffalo Pebblesnail ''Gillia altilis''
{{Taxonbar, from=Q3138789, from2=Q27216652 Lithoglyphidae