Planorbidae,

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 ramshorn snails or ram's horn snails, is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

of air-breathing

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 ...

s, aquatic

pulmonate Pulmonata or pulmonates, is an informal group (previously an Order (biology), order, and before that a Class (biology), subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a Respiratory system of gastro ...

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 ...

molluscs. Unlike most molluscs, the blood of ram's horn snails contains iron-based

hemoglobin Hemoglobin (haemoglobin BrE) (from the Greek word αἷμα, ''haîma'' 'blood' + Latin ''globus'' 'ball, sphere' + ''-in'') (), abbreviated Hb or Hgb, is the iron-containing oxygen-transport metalloprotein present in red blood cells (erythroc ...

instead of copper-based hemocyanin. As a result, planorbids are able to breathe

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...

more efficiently than other molluscs. The presence of hemoglobin gives the body a reddish colour. This is especially apparent in

albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and pink or blue eyes. Individuals with the condition are referred to as albino. Varied use and interpretation of the term ...

animals. Being air breathers like other '' Panpulmonata'', planorbids do not have

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 ar ...

s, but instead have a

lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of ...

. The foot and head of planorbids are rather small, while their thread-like tentacles are relatively long. Many of the species in this family have coiled shells that are planispiral, in other words, the shells are more or less coiled flat, rather than having an elevated

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires a ...

as is the case in most

gastropod shell The gastropod shell is part of the body of a Gastropoda, gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium s ...

s. Although they carry their shell in a way that makes it appear to be

dextral Sinistral and dextral, in some scientific fields, are the two types of chirality (" handedness") or relative direction. The terms are derived from the Latin words for "left" (''sinister'') and "right" (''dexter''). Other disciplines use differe ...

, the shell of coiled planorbids is in fact sinistral in coiling, but is carried upside down, which makes it appear to be dextral.

General taxonomic context

For several taxa, no consensus exists as to whether the taxa should even be assigned to the

Planorbidae. This is certainly the case with the freshwater limpets ''

Ferrissia ''Ferrissia'' is a genus of small, air-breathing freshwater limpets, aquatic gastropod mollusks in the family Planorbidae, the ram's horn snails and their allies. Species Species within the genus ''Ferrissia'' include: * '' Ferrissia baconi'' ...

'', and ''

Ancylus ''Ancylus'' is a genus of very small, freshwater, air-breathing limpets. They are aquatic pulmonate gastropod mollusks in the tribe Ancylini within the family Planorbidae, the ram's horn snails and their allies.Bouchet, P.; Rosenberg, G. (2014 ...

''. Both of these genera have sometimes been assigned to the family

Lymnaeidae Lymnaeidae, common name the pond snails, is a taxonomic family of small to large air-breathing freshwater snails, aquatic pulmonate gastropod mollusks, that belong to the clade Hygrophila. Lymnaeidae is the only family within the superf ...

. Alternatively sometimes each one of them is raised to the level of a family. However, according to the

taxonomy of the Gastropoda (Bouchet & Rocroi, 2005) The taxonomy of the Gastropoda as it was revised in 2005 by Philippe Bouchet and Jean-Pierre Rocroi is a system for the scientific classification of gastropod mollusks. (Gastropods are a taxonomic class of animals which consists of snails and s ...

, these genera are currently placed in the tribe

Ancylini Ancylini is a tribe of small, freshwater, air-breathing limpets, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails and their allies. This tribe used to be treated as a family; the current taxonomic placement w ...

within the family Planorbidae, and that is the taxonomic system that is followed here.

2005 taxonomy

According to the

, this family consists of the following subfamilies: * subfamily Planorbinae Rafinesque, 1815 ** tribe Planorbini Rafinesque, 1815 - synonyms: Choanomphalinae Fisher & Crosse, 1880; Orygoceratidae Brusina, 1882 ** tribe

Rafinesque, 1815 - synonym: Pseudancylinae Walker, 1923 (inv.) ** tribe Biomphalariini Watson, 1954 - synonyms: Acrorbini Starobogatov, 1958; Drepanothrematini Zilch, 1959; Taphiinae Harry & Hubendick, 1964 ** tribe Planorbulini Pilsbry, 1934 ** tribe Segmentinini Baker, 1945 * subfamily Bulininae Fischer & Crosse, 1880 ** tribe Bulinini Fischer & Crosse, 1880 - synonyms: Laevapicinae Hannibal, 1912; Isidorinae Annandale, 1922; Gundlachiinae Starobogatov, 1967 ** tribe Coretini Gray, 1847 - synonyms: Pompholicinae Dall, 1866 (inv.); Camptoceratinae Dall, 1870; Megasystrophinae Tryon, 1871 (inv.); Pompholycodeinae Lindholm, 1927; Helisomatinae Baker, 1928; Bayardellini Starobogatov & Prozorova, 1990; Planorbariini Starobogatov, 1990 ** tribe Miratestini Sararsin & Sarasin, 1897 - synonyms: Ferrissiinae Walker, 1917; Ancylastrinae Walker, 1923; Protancylinae Walker, 1923; Physastrinae Starobogatov, 1958; Ameriannini Zilch, 1959; Patelloplanorbidae Franc, 1968 ** tribe Plesiophysini Bequaert & Clench, 1939 * subfamily Neoplanorbinae Hannibal, 1912 - synonym: Payettiinae Dall, 1924 * subfamily Rhodacmeinae Walker, 1917

2007 taxonomy for part of the family

Albrecht ''et al.'' (2007)Albrecht C., Kuhn K. & Streit B. (2007). "A molecular phylogeny of Planorboidea (Gastropoda, Pulmonata): insights from enhanced taxon sampling". '' Zoologica Scripta'' 36: 27-39.. analyzed a limited number of genera of Planorbidae, based on sequences of mitochondrial 18S ribosomal DNA and cytochrome-c oxidase I (COI) genes, and on the basis of the results, they rearranged the taxonomy like this: "A-clade" sensu Albrecht ''et al.'' (2007) * ''

Burnupia ''Burnupia'' is a genus of small freshwater snails or limpets, aquatic gastropod mollusks that are traditionally placed in the family Planorbidae. However, according to the molecular markers ( COI, 18S rRNA), the genus ''Burnupia'' differs fr ...

'' Walker, 1912 Tribus Bulinini * '' Bulinus'' Müller, 1781 * '' Indoplanorbis'' Annandale, 1921 Tribus

Rafinesque-Schmaltz, 1815 * ''

'' Müller, 1774 * ''

'' Walker, 1903 * '' Gundlachia'' Pfeiffer, 1849 * ''

Laevapex ''Laevapex'' is a genus of small, freshwater, air-breathing limpets, aquatic pulmonate gastropod molluscs in the family Planorbidae, the ram's horn snails and their allies. Geographic distribution The genus has a New World distribution ...

'' Walker, 1903 * '' Hebetancylus'' Pilsbry, 1914 "B-clade" sensu Albrecht ''et al.'' (2007) * '' Glyptophysa'' Crosse, 1872 * '' Protancylus'' Sarasin, 1897 * '' Kessneria'' Walker & Ponder, 2001 * '' Leichhardtia'' Walker, 1988 Tribus Camptoceratini * '' Planorbarius'' Duméril 1806 Tribus Planorbini * '' Anisus'' Studer, 1820 * '' Bathyomphalus'' Charpentier, 1837 * '' Gyraulus'' Charpentier, 1837 * '' Hovorbis'' Brown & Mandahl-Barth, 1973 * '' Choanomphalus'' Gerstfeldt, 1859 * '' Planorbis'' Müller 1774 Tribus Segmentinini * '' Segmentina'' Fleming, 1818 * '' Hippeutis'' Charpentier, 1837 * '' Polypylis'' Pilsbry, 1906 "C-Clade" sensu Albrecht ''et al.'' (2007) * ''

Biomphalaria ''Biomphalaria'' is a genus of air-breathing freshwater snails, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails and their allies.MolluscaBase (2018). Biomphalaria Preston, 1910. Accessed through: World Regi ...

'' Preston, 1910 * '' Menetus'' Adams & Adams, 1855 * ''

Planorbella ''Planorbella'' is a genus of freshwater air-breathing snails, aquatic pulmonate gastropod mollusks in the family Planorbidae, the ram's horn snails, or planorbids, which all have sinistral, or left-coiling, shells. Ecology Species in this genu ...

'' Haldeman, 1843 * '' Planorbula'' Haldeman, 1843

Cladogram

The following is a

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

that shows the phylogenic relationships within the Planorbidae according to Albrecht 2007:

Genera

The type genus of this family is ''Planorbis'' Müller. The following list of genera is organized according to the 2005 taxonomy, because Albrecht's 2007 taxonomy is not available for all genera of Planorbidae. Genera in the family Planorbidae include (subgenera listed according to Glöer (2002): * subfamily Planorbinae Rafinesque, 1815 Anisus septegyrus1pl

*** '' Anisus'' S. Studer, 1820 **** subgenus '' Disculifer'' Boettger, 1944 *** '' Bathyomphalus'' Charpentier, 1837 *** '' Gyraulus'' Charpentier, 1837 **** subgenus '' Torquis'' Dall, 1905 **** subgenus '' Lamorbis'' Starobogatov, 1967 **** subgenus '' Armiger'' Hartmann, 1843 *** '' Hippeutis'' Charpentier, 1837 ** tribe

Rafinesque, 1815 *** ''

'' Müller, 1773 - type genus of tribe Ancylini ** tribe Biomphalariini Watson, 1954 *** ''

'' Preston, 1910 - type genus of tribe Biomphalariini *** ''

Drepanotrema ''Drepanotrema'' is a genus of molluscs in the family Planorbidae Planorbidae, common name the ramshorn snails or ram's horn snails, is a family of air-breathing freshwater snails, aquatic pulmonate gastropod molluscs. Unlike most mollusc ...

'' Crosse & Fischer, 1880 ** tribe Planorbini Rafinesque, 1815 *** '' Afrogyrorbis'' Starobogatov, 1967Starobogatov, Y. I. (1967). On the systematization of freshwater pulmonate molluscs. ''Trudy Zoologicheskogo Instituta, Leningrad'', 42, 280–304. *** '' Planorbis'' Müller, 1773 ** tribe Planorbulini Pilsbry, 1934 *** '' Planorbula'' Haldeman, 1840 - type genus of tribe Planorbulini ** tribe Segmentinini Baker, 1945 *** '' Segmentina'' Fleming, 1818 - type genus of tribe Segmentinini * subfamily Bulininae Fischer & Crosse, 1880 *** '' Indoplanorbis'' Annandale & Prashad, 1920 - contains one species ''

Indoplanorbis exustus ''Indoplanorbis'' is a genus of air-breathing freshwater snail. Its only member species is ''Indoplanorbis exustus'', an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails. The species is widely distributed ac ...

''Liu L et al. (2010) "The phylogeography of ''Indoplanorbis exustus'' (Gastropoda: Planorbidae) in Asia". '' Parasites & Vectors'' 3: 57. . *** '' Planorbarius'' Duméril, 1806 *** ''

'' Haldeman, 1842 *** '' Menetus'' Adams & Adams, 1855 **** subgenus '' Dilatata'' Clessin, 1885 ** tribe Bulinini Fischer & Crosse, 1880 *** '' Bulinus'' Müller, 1781 - type genus of subfamily Bulininae *** '' Gundlachia'' Pfeiffer, 1849 ** tribe Coretini Gray, 1847 *** '' Coretus'' Gray, 1847 - type genus of tribe Coretini ** tribe Miratestini Sarasin & Sarasin, 1897 *** '' Miratesta'' Sarasin & Sarasin, 1897 - type genus of tribe Miratestini *** '' Amerianna'' Strand, 1928 *** ''

'' Walker, 1903 **** '' Pettancyclus'' Iredale, 1943 ** tribe Plesiophysini Bequaert & Clench, 1939 *** '' Plesiophysa'' Fischer, 1883 - type genus of tribe Plesiophysini * subfamily Neoplanorbinae Hannibal, 1912 *** '' Neoplanorbis'' Pilsbry, 1906 - type genus of subfamily Neoplanorbinae * subfamily Rhodacmeinae Walker, 1917 *** ''

Rhodacmea ''Rhodacmea'' is a genus of small freshwater snails or limpets, aquatic gastropod mollusks in the family Planorbidae, the ram's horn snails and their allies.Ó Foighil D., Li J., Lee T., Johnson P., Evans R. & Burch J. B. (2011). "Conservatio ...

'' Walker, 1917 - type genus of subfamily Rhodacmeinae Subfamily = ? (other genera that are not yet sorted are listed here) * '' Acrorbis'' Odhner, 1937 * '' Africanogyrus'' Özdikmen & Darilmaz, 2007
- synonym: '' Afrogyrus'' Brown & Mandahl-Barth, 1973 * '' Afroplanorbis'' Thiele, 1931 * '' Amphigyra'' Pilsbry, 1906 * '' Anisopsis'' Sandberger, 1875 * '' Antillorbis'' Harry & Hubendick, 1964 * '' Armigerus'' Clessin, 1884 * '' Australorbis'' Pilsbry, 1934 * '' Bayardella'' Burch, 1977 * '' Berellaia'' Laubrière & Carez, 1880 * '' Camptoceras'' Benson, 1843 * '' Camptoceratops'' Wenz, 1923 * '' Carinifex'' Binney, 1865 * '' Carinogyraulis'' Polinski, 1929 * '' Ceratophallus'' Brown & Mandahl-Barth, 1973 * '' Choanomphalus'' Gerstfeldt, 1859 * '' Culmenella'' Clench, 1927Mollusc Specialist Group (1996)
''Culmenella rezvoji''
In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. . Downloaded on 08 March 2011. * '' Fossulorbis'' Pilsbry, 1934 * '' Glyptophysa'' Crosse, 1872 * '' Helicorbis'' Benson, 1855 * '' Helisoma'' Swainson, 1840 * '' Intha'' Annandale, 1922 * '' Isidorella'' Tate, 1896 * '' Kessneria'' Walker & Ponder, 2001 * '' Leichhardtia'' Walker, 1988 * '' Lentorbis'' Mandahl-Barth, 1954 * '' Macrophysa'' (Meek) Dall, 1870 * '' Paraplanorbis'' Hanna, 1922 * '' Patelloplanorbis'' Hubendick, 1957 * '' Pecosorbis'' Taylor, 1985 * '' Pentagoniostoma'' Branson, 1935 * '' Perrinilla'' Hannibal, 1912 * '' Physastra'' Tapparone-Canefri, 1883 * '' Physopsis'' Krauss, 1848 * '' Pingiella'' Baker, 1945 * '' Pitharella'' Edwards, 1860 * '' Planorbifex'' Pilsbry, 1935 * '' Planorbina'' Haldeman, 1842 * '' Platyphysa'' Fischer, 1883 * '' Platytaphius'' Pilsbry, 1924 * '' Polypylis'' Pilsbry, 1906 * '' Promenetus'' Baker, 1935 * '' Protancylus'' Sarasin & Sarasin, 1897 * '' Pygmanisus'' Iredale, 1943 * '' Segmentorbis'' Mandahl-Barth, 1954 * '' Sineancylus'' Gutiérrez Gregoric, 2014 * '' Syrioplanorbis'' Baker, 1945 * '' Trochorbis'' Benson, 1855 * '' Vorticifex'' Meek in Dall, 1870 The genus '' Camptoceratops'' Wenz, 1923 is no longer considered to be a planorbid. It was recognised by Curry (1965, p. 360) as a euthecosomatous pteropod (Heterobranchia) (note by Arie W. Janssen, 092507). The generic name ''Taphius'' Adams & Adams, 1855 is a synonym for ''

''.

Shell description

The shells of most species in this family are disk-like or button-like, being coiled in one plane, although several groups have shells that are more higher-spired, and some are

limpet Limpets are a group of aquatic snails that exhibit a conical gastropod shell, shell shape (patelliform) and a strong, muscular foot. Limpets are members of the class Gastropoda, but are polyphyletic, meaning the various groups called "limpets" ...

-like. All coiled shell Planorbidae are sinistral in their shell coiling, as is proved by their internal anatomy (the respiratory and the genital orifice are situated on the left side), however the animals carry their shells with what would normally be the ventral (i.e. umbilical) surface uppermost, and because of this, the shells appear to be dextral. Indeed, formerly planorbids were thought to have dextral shells, and so species of this family were figured as if they had

shells. Although it is now understood that these species are sinistral in shell coiling, disk-like Planorbid shells are often still shown in illustrations oriented as if they were dextral. Most species of coiled planorbids have a rather thin and moderately smooth shell, although more distinct sculpture such as a keel occurs in, and is diagnostic of, certain species. In the flat, keeled species, the whorls tend to overlap. 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 ...

has a sharp outer lip. A peristome can be present, but often the lip is not thickened nor reflected. Those planorbid species which have a high-spired shell may have a narrow umbilicus, but frequently this is covered by callus. In height most species vary between 6 mm and 6 cm, however, disk-like shells are usually less than about 2 cm in maximum dimension. Like all pulmonate aquatic snails, ramshorn shells do not have an operculum to close the shell aperture.

Sinistral shells

Flat-coiled planorbid

s are hard to understand in terms of their coiling and orientation. Many of the shells of species in this family are almost planispiral in coiling such that one side of the shell often looks rather like the other side, but it is important to bear in mind that nonetheless there is an umbilical side and a

side of the shell. In addition these are in fact sinistral shells, despite the fact that the snail carries its shell as if it were a normal dextral shell. To make sense of the shell coiling, the following facts are useful: * In life, these pond snails hold their shells ''upside down'' compared to the normal gastropod shell orientation, with the umbilicus facing upwards. * The

of the shell is quite sunken in many species. In addition, it is carried facing downwards. * The umbilicus of the shell is very wide and shallow. * In some species the umbilicus is not as deeply "dished" as the sunken spire is, so superficially it can be hard to tell one from the other. However, once it is understood that the planorbid shell is sinistral, if the shell is held with the

on the left and facing the observer, then the sunken spire side of the shell is uppermost. This is a convenience for understanding the shell, but is the opposite of the way the shell is actually carried in life. The side of the shell which is in fact the spire (a sunken spire) faces ''down'' in the living animal, contrary to what is the case in almost all other shelled gastropods. Because the shell is carried "upside down" like this, the

of the shell is angled to face downwards also, so the aperture faces a little towards the spire, not away from it, as is usually the case in other shelled gastropods.

Habitat

Most species of planorbids live only in fresh water, such as ponds, lakes, and slow moving rivers. A minority of species are able to survive in brackish water.

Geological history

Ancestors of ramshorn snails are known with certainty since the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

period. Modern taxa developed in the

Geographical distribution

Species in this family occur worldwide. In Northwest Europe about 20 species are known (including non-indigenous species). In this region, various extinct taxa are known to have occurred, starting in the

period.

References

* Gittenberger, E., Janssen, A.W., Kuijper, W.J., Kuiper, J.G.J., Meijer, T., Velde, G. van der & Vries, J.N. de (1998) ''De Nederlandse zoetwatermollusken. Recente en fossiele weekdieren uit zoet en brak water'' Nederlandse Fauna 2. Nationaal Natuurhistorisch Museum Naturalis, KNNV Uitgeverij & EIS-Nederland, Leiden, 288 pp. * Fischer, P.H. (1880-1887) ''Manuel de Conchyliologie et de Paléontologie conchyliologique ou histoire naturelle des Mollusques vivants et fossiles suivi d'un appendice sur les Brachiopodes par D. Oehlert.'' – XXIV + 1369 pp. * (German) Thiele, J. (1929-1935) ''Handbuch der Systematischen Weichtierkunde.'' Jena, (1), 1-376, 1929; (2), 377-778, 1931; 779-1022, 1934; 1023-1134, 1935. * Vaught, K.C. (1989) ''A classification of living mollusca.'' American Malacologists Inc., Melbourne USA, & 0-915826-22-6, 195 pp. * (German) Wenz, W. (1923-1930) ''Gastropoda extramarina tertiaria.'' Fossilium Catalogus I. (4 vols.), 3387 pp. * (German) Zilch, A. (1959-1960) ''Euthyneura.'' In: H. Schindewolf (ed.), Handbuch der Paläozoologie, 6(2): pp. I-XII + 1-834.

External links

*
NCBI Taxonomy Browser: Planorbidae
*
Systema naturae 2000 (classification) - Taxon: Planorbidae
*
ITIS: Planorbidae
* http://mkohl1.net/Planorbidae.html
Frank Collins Baker, ''The Molluscan Family Planorbidae'', The University of Illinois press, Urbana, 1945
{{taxonbar, from=Q1475666 Gastropod families Taxa named by Constantine Samuel Rafinesque