Thickshell pondsnail
Encyclopedia
Stagnicola utahensis, common name the thickshell pondsnail, is a species
of air-breathing freshwater snail
, an aquatic
pulmonate gastropod mollusk in the family Lymnaeidae
, the pond snails.
is globose, somewhat umbilicated and irregularly costate. The color of the shell is light horn and nearly pellucid. The spire
is rather small and conical. The shell has from 4 to 4 and half convex whorls
, that are somewhat flattened above, giving rather a shouldered appearance to the whorls. Whorls are rapidly increasing in size. The last whorl
is inflated, with numerous rather marked transverse costae and minutely wrinkled. The suture is somewhat deep, regularly impressed.
The aperture
is elongately ovate, effuse, approaching patulous and pearly white within. The outer lip is simple and its margin is connected by a slight calcareous deposit. The columella is somewhat twisted, but straight in front.
The average width of the shell of Stagnicola utahensis is 7.10 mm. The average height of the shell is 13.40 mm. The maximum width of the shell is 8.88 mm. The height of the shell is 16.82 mm. The width of the aperture is 5.90 mm. The height of the aperure is 9.00 mm.
and it is known only from Utah Lake
. The type locality is Lake Utah, Lehi, Utah
.
The species was "rare" in the lake Utah in 1880s already.
The last living examples are reported from early 1930s.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of air-breathing freshwater snail
Freshwater snail
A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....
, an aquatic
Aquatic animal
An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...
pulmonate gastropod mollusk in the family Lymnaeidae
Lymnaeidae
Lymnaeidae is a taxonomic family of small to large air-breathing freshwater snails, aquatic pulmonate gastropod mollusks, that belong to the clade Hygrophila....
, the pond snails.
Shell description
The shellGastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
is globose, somewhat umbilicated and irregularly costate. The color of the shell is light horn and nearly pellucid. The spire
Spire (mollusc)
A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...
is rather small and conical. The shell has from 4 to 4 and half convex whorls
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
, that are somewhat flattened above, giving rather a shouldered appearance to the whorls. Whorls are rapidly increasing in size. The last whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
is inflated, with numerous rather marked transverse costae and minutely wrinkled. The suture is somewhat deep, regularly impressed.
The aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
is elongately ovate, effuse, approaching patulous and pearly white within. The outer lip is simple and its margin is connected by a slight calcareous deposit. The columella is somewhat twisted, but straight in front.
The average width of the shell of Stagnicola utahensis is 7.10 mm. The average height of the shell is 13.40 mm. The maximum width of the shell is 8.88 mm. The height of the shell is 16.82 mm. The width of the aperture is 5.90 mm. The height of the aperure is 9.00 mm.
Distribution
This species is endemic to the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and it is known only from Utah Lake
Utah Lake
Utah Lake is a freshwater lake in the U.S. state of Utah. On the western side of Utah Valley, the lake is overlooked by Mount Timpanogos and Mount Nebo. The lake's only river outlet, the Jordan River, is a tributary of the Great Salt Lake and is highly regulated with pumps. Evaporation accounts...
. The type locality is Lake Utah, Lehi, Utah
Lehi, Utah
-Attractions:Lehi Roller MillsLehi Roller Mills was founded in 1906 by a co-op of farmers. George G. Robinson purchased the mill in 1910, and since then it has remained in the family. It is run today by grandson R. Sherman Robinson....
.
The species was "rare" in the lake Utah in 1880s already.
The last living examples are reported from early 1930s.