Hygrophila is a
taxonomic superorder
Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...
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 gastropod 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 es ...
s within the clade
Panpulmonata
Panpulmonata is a taxonomic clade of snails and slugs in the clade Heterobranchia within the clade Euthyneura.
Panpulmonata was established as a new taxon by Jörger et al. in October 2010.
The older name "Pulmonata" referred to a group of gas ...
.
[MolluscaBase eds. (2020). MolluscaBase. Hygrophila. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=382243 on 2020-12-14]
The families in this clade are basically air-breathing freshwater snails including freshwater
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" ...
s. The three families with the greatest number of species are the Lymnaeidae (pond snails), the Planorbidae (ramshorn snails) and the Physidae (pouch or bubble snails). These are found in ponds, creeks, ditches, and shallow lakes nearly worldwide.
The snails in this clade have their eyes located at the base of their tentacles, rather than at the tips, as in the true land snails
Stylommatophora
Stylommatophora is an orderPhilippe Bouchet, Jean-Pierre Rocroi, Bernhard Hausdorf, Andrzej Kaim, Yasunori Kano, Alexander Nützel, Pavel Parkhaev, Michael Schrödl and Ellen E. Strong. 2017. Revised Classification, Nomenclator and Typification ...
. They have shells that are thin, translucent, and relatively colorless, and they lack an
operculum.
Taxonomy
1997 taxonomy
In the older
taxonomy of the Gastropoda (Ponder & Lindberg, 1997) these families were placed in the suborder Basommatophora.
2005 taxonomy
Hygrophila has been a clade in the informal group
Basommatophora
Basommatophora was a term that was previously used as a taxonomic informal group, a group of snails within the informal group Pulmonata, the air-breathing slugs and snails. According to the taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), wh ...
within the
Pulmonata
Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group include ...
.
Clade Hygrophila:
*Superfamily
Chilinoidea Dall, 1870
**Family
Chilinidae Dall, 1870
**Family
Latiidae
''Latia'' is a genus of very small, air-breathing freshwater snails or limpets, aquatic pulmonate gastropod molluscs in the superfamily Chilinoidea.
''Latia'' is the only genus in the family Latiidae.
Species in this genus are the only fres ...
Hutton, 1882
*Superfamily
Acroloxoidea Thiele, 1931
**Family
Acroloxidae
Acroloxidae, commonly known as river limpets, are a taxonomic family of very small, freshwater snails, aquatic pulmonate gastropod limpet-like mollusks with a simple flattened conical shell in the clade Hygrophila.
Acroloxidae is the only fam ...
Thiele, 1931
*Superfamily
Lymnaeoidea Rafinesque, 1815
**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 superfam ...
Rafinesque, 1815
*Superfamily
Planorboidea Rafinesque, 1815
**Family
Planorbidae Rafinesque, 1815
**Family
Physidae
Physidae, common name the bladder snails, is a monophyletic taxonomic family of small air-breathing freshwater snails, aquatic pulmonate gastropod molluscs in the superfamily Lymnaeoidea .MolluscaBase eds. (2021). MolluscaBase. Physidae F ...
Fitzinger, 1833
Note: what was previously the family
Ancylidae has been demoted in the new taxonomy to the status of tribe Ancylini Rafinesque, 1815 within the subfamily Planorbinae Rafinesque, 1815 of the family
Planorbidae Rafinesque, 1815.
2010 taxonomy
Basommatophora (
Siphonarioidea and
Amphiboloidea and Hygrophila) have been found
polyphyletic
A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...
and so Jörger et al. (2010)
[Jörger K. M., Stöger I., Kano Y., Fukuda H., Knebelsberger T. & Schrödl M. (2010). "On the origin of Acochlidia and other enigmatic euthyneuran gastropods, with implications for the systematics of Heterobranchia". '']BMC Evolutionary Biology
''BMC Ecology and Evolution'' (since January 2021), previously ''BMC Evolutionary Biology'' (2001–2020), is a peer-reviewed open access scientific journal covering all fields of evolutionary biology, including phylogenetics and palaeontology. It ...
'' 10: 323. . have moved Hygrophila to
Panpulmonata
Panpulmonata is a taxonomic clade of snails and slugs in the clade Heterobranchia within the clade Euthyneura.
Panpulmonata was established as a new taxon by Jörger et al. in October 2010.
The older name "Pulmonata" referred to a group of gas ...
.
2020 taxonomy
A comprehensive molecular phylogenetic analysis of Hygrophila based on 3112 sites of the large subunit and 5.8S
ribosomal RNA
Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosomal ...
genes resulted in a proposal of a new taxonomic revision of the group.
*
Chilinoidea Dall, 1870
*
Lymnaeoidea Rafinesque, 1815
;Synonyms:
* Acroloxoidea
Thiele, 1931: synonym of Lymnaeoidea
Rafinesque, 1815
* Planorboidea
Rafinesque, 1815: synonym of Lymnaeoidea
Rafinesque, 1815
References
{{Taxonbar, from=Q872645
Panpulmonata