Pyrgophorus spinosus
Encyclopedia
Pyrgophorus spinosus, common name
the spiny crownsnail, is a species
of very small freshwater snail
with a gill
and an operculum
, an aquatic
gastropod mollusk in the family Hydrobiidae
.
in 1886 as Pyrgulopsis spinosus but until César Marie Félix Ancey
established the new genus Pyrgophorus
in 1888, it was not clear what genus this species belonged to.
is minute, imperforate, turreted and unicarinate. The carina is modified into spinous processes on last three whorls. The carina is darker colored than balance of shell. The shell has 5-5½ whorls
. The first two whorls are rounded, destitute of spines
or carina. The last three whorls are somewhat geniculate, angled at location of carina. The body whorl
is large, sometimes with an occasional spine below the carina. The epidermis is light horn in color, nearly white at apex
, with microscopic longitudinal revolving striae and shining.
The aperture
is roundly ovate, slightly longer than broad and rounded anteriorly. The peristome is not continuous. The peristome is sharp, simple, slightly reflected near the columella, suggesting a faint umbilicus. The suture is slightly impressed.
The width of the shell is 1.52-2.34 mm. The height of the shell is 3.00-3.86 mm.
The operculum
is spiral and reddish horn in color.
, on rocky bottoms.
(species undetermined), and Bythinella
(species undetermined) in 1886.
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
the spiny crownsnail, is a species
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 very small freshwater snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
with a gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
and an operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
, 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...
gastropod mollusk in the family Hydrobiidae
Hydrobiidae
Hydrobiidae, common name mud snails, is a large cosmopolitan taxonomic family of very small freshwater snails and brackish water snails that have an operculum, aquatic gastropod mollusks in the clade Littorinimorpha.- Distribution :...
.
Taxonomy
Pyrgophorus spinosus was described by Richard Ellsworth Call and by Henry Augustus PilsbryHenry Augustus Pilsbry
Henry Augustus Pilsbry was an American biologist, malacologist and carcinologist, among other areas of study. He was a dominant presence in many fields of invertebrate taxonomy for the better part of a century...
in 1886 as Pyrgulopsis spinosus but until César Marie Félix Ancey
César Marie Félix Ancey
César Marie Félix Ancey was a French conchologist and entomologist.He was for 23 years ‘conservateur’ of collections for Charles Oberthür at Rennes...
established the new genus Pyrgophorus
Pyrgophorus
Pyrgophorus is a genus of very small freshwater snails with a gill and an operculum, aquatic gastropod molluscs in the family Hydrobiidae. They- Species :Species in the genus Pyrgophorus include:* Pyrgophorus parvulus...
in 1888, it was not clear what genus this species belonged to.
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 minute, imperforate, turreted and unicarinate. The carina is modified into spinous processes on last three whorls. The carina is darker colored than balance of shell. The shell has 5-5½ 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...
. The first two whorls are rounded, destitute of spines
or carina. The last three whorls are somewhat geniculate, angled at location of carina. The body 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 large, sometimes with an occasional spine below the carina. The epidermis is light horn in color, nearly white at apex
Apex (mollusc)
Apex is an anatomical term for the tip of the mollusc shell of a gastropod, scaphopod, or cephalopod mollusc.-Gastropods:The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod...
, with microscopic longitudinal revolving striae and shining.
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 roundly ovate, slightly longer than broad and rounded anteriorly. The peristome is not continuous. The peristome is sharp, simple, slightly reflected near the columella, suggesting a faint umbilicus. The suture is slightly impressed.
The width of the shell is 1.52-2.34 mm. The height of the shell is 3.00-3.86 mm.
The operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
is spiral and reddish horn in color.
Distribution
The type locality is Comal Creek, a clear stream at New Braunfels, TexasTexas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, on rocky bottoms.
Habitat
Pyrgophorus spinosus inhabited its type locality altogether with numerous specimens of Goniobasis pleuristriata Say, AmnicolaAmnicola
Amnicola is a genus of very small freshwater snails which have an operculum. Amnicola species are aquatic prosobranch gastropod mollusks in the family Amnicolidae according to the taxonomy of the Gastropoda ....
(species undetermined), and Bythinella
Bythinella
Bythinella is a genus of very small freshwater snails, an aquatic gastropod mollusk in the family Amnicolidae ....
(species undetermined) in 1886.