Physella gyrina
Encyclopedia
Physella gyrina common name the "tadpole physa", is a species
of small, left-handed or sinistral
, air-breathing freshwater snail
, an aquatic
pulmonate gastropod mollusk in the family Physidae.
that are sinistral, which means that if you hold the shell such that the spire
is pointing up, and the aperture is facing you, the aperture
is on the left-hand side.
The shells of Physella species have a long and large aperture, a pointed spire, and no operculum. The shells are thin and corneous and rather transparent.
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 small, left-handed or sinistral
Sinistral
Sinistral and dextral are scientific terms that describe chirality or relative direction in a number of disciplines.The terms are derived from the Latin words for “left” and “right” ....
, 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 Physidae.
Shell description
Snails in the family Physidae have shellsGastropod 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...
that are sinistral, which means that if you hold the shell such that 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 pointing up, and the aperture is facing you, 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 on the left-hand side.
The shells of Physella species have a long and large aperture, a pointed spire, and no operculum. The shells are thin and corneous and rather transparent.
Distribution
This species is known to occur in:- the USA - indigenous
- Great Britain - introduced
- Ireland - introduced
- Spain
External links
- AnimalBaseAnimalBaseAnimalBase is a project brought to life in 2004 and is maintained by the University of Göttingen, Germany. The goal of the AnimalBase project is to digitize early zoological literature, provide copyright-free open access to zoological works, and provide manually verified lists of names of...
info at: http://www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBase/home/species?id=2841 - ITIS info: http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=76735