''Pyrgophorus spinosus'',

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 contrast ...

the spiny crownsnail, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of very small

freshwater snail Freshwater snails are gastropod mollusks which 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 ...

with a

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

and an operculum, an aquatic

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

in the family Hydrobiidae.

Taxonomy

''Pyrgophorus spinosus'' was described by

Richard Ellsworth Call Richard is a male given name. It originates, via Old French, from Old Frankish and is a compound of the words descending from Proto-Germanic ''*rīk-'' 'ruler, leader, king' and ''*hardu-'' 'strong, brave, hardy', and it therefore means 'strong ...

and by

Henry Augustus Pilsbry Henry Augustus Pilsbry (7 December 1862 – 26 October 1957) 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 centu ...

in 1886 as ''Pyrgulopsis spinosus'' but until

César Marie Félix Ancey César Marie Félix Ancey (15 November 1860 – 10 October 1906) was a French conchologist and entomologist. For 23 years Ancey was ‘conservateur’ of collections for Charles Oberthür (1845–1924) at Rennes. Ancey was then a ‘fonctionna ...

established the new genus '' Pyrgophorus'' in 1888, it was not clear what genus this species belonged to.Pilsbry H. A. 1886. ''Description of a New Hydrobia, with Notes on Other Rissoidae''
Proceeding Davenport Academy of Natural Sciences, volume V.page 34

Shell description

The shell 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 A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral d ...

. 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 The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the b ...

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 In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

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.

Distribution

The type locality is Comal Creek, a clear stream at

New Braunfels New Braunfels ( ) is a city in Comal County, Texas, Comal and Guadalupe County, Texas, Guadalupe counties in the U.S. state of Texas known for its German Texan heritage. It is the county seat, seat of Comal County. The city covers and had a popula ...

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

, on rocky bottoms.

Habitat

In 1886, ''Pyrgophorus spinosus'' inhabited its type locality along with numerous specimens of '' Goniobasis pleuristriata'' Say, ''

Amnicola ''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 (Bouchet & Rocroi, 2005). '' ...

'' (species undetermined), and ''

Bythinella ''Bythinella'' is a genus of very small freshwater snails, an aquatic gastropod mollusk in the family Bythinellidae (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). These gonochoristic snails are small animals, with a s ...

'' (species undetermined).

References

This article incorporates public domain text from reference. {{DEFAULTSORT:Pyrgophorus Spinosus Hydrobiidae Gastropods described in 1886