Lower Heterobranchia, also known as the Allogastropoda, is a group of rather specialized, highly evolved

sea slug Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are gastropods, i.e. they are sea snails (marine gastropod mollusks) that over evolutionary time ...

s and sea snails, ( marine gastropod mollusks) within the subclass

Heterobranchia Heterobranchia, the ''heterobranchs'' (meaning "different-gilled snails"), is a taxonomic clade of snails and slugs, which includes marine, aquatic and terrestrial gastropod mollusks. Heterobranchia is one of the main clades of gastropods. Cur ...

. WoRMS (2020). "Lower Heterobranchia". Accessed at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=1054700 on 2020-05-16 Although the great majority of Lower Heterobranchs are indeed marine, a few have succeeded in making the transition to freshwater.

Description

The

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...

shapes in this group are typically those that are seen in the sundial, pyramid, rissoella and orbitestellid families of snails. Bactroptyxis trachaea 041811

Taxonomy

2005 taxonomy

In the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005, the Lower Heterobranchia is an Informal Group. Superfamilies within the Lower Heterobranchia include: *Unassigned to a superfamily (orbitestellid-shells) ** Family

Cimidae The Cimidae is a Taxonomy (biology), taxonomic family (biology), family of sea snails, Marine (ocean), marine gastropod mollusks in the infraclass Lower Heterobranchia.MolluscaBase eds. (2021). MolluscaBase. Cimidae Warén, 1993. Accessed through ...

** † Family Dolomitellidae ** † Family Heterosubulitidae ** † Family Kuskokwimiidae ** † Family Misurinellidae **Family Orbitestellidae **Family Tjaernoeiidae **Family Xylodisculidae * superfamily

Acteonoidea Acteonoidea is a superfamily of sea snails, or bubble snails, marine gastropod mollusks. Taxonomy In the taxonomy of Bouchet & Rocroi (2005), the superfamily Acteonoidea has been included into the informal group "Lower Heterobranchia" ( ...

* superfamily Architectonicoidea * superfamily

Glacidorboidea The Glacidorbidae is a taxonomic family of freshwater snails. Taxonomy 2005 taxonomy Glacidorbidae is the only family in the superfamily Glacidorboidea. Glacidorboidea has been classified within the informal group Lower Heterobranchia in th ...

* superfamily Mathildoidea * † superfamily

Nerineoidea †Nerineoidea is a superfamily of extinct sea snails, fossil marine gastropod mollusks in the informal group Lower Heterobranchia. Families Families within the superfamily Nerineoidea include: * † Family Nerineidae The Nerineidae is an ...

* superfamily Omalogyroidea * superfamily

Pyramidelloidea Pyramidelloidea is a superfamily of mostly very small sea snails, marine gastropod mollusks and micromollusks within the clade Panpulmonata. This is a voluminous taxon: above the species level close to 400 named taxa are referred to this g ...

* superfamily Ringiculoidea * superfamily Rissoelloidea * † superfamily Streptacidoidea * superfamily Valvatoidea (Taxa that are exclusively fossil are indicated with a dagger †) For a more detailed taxonomy see: Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)#Informal group "Lower Heterobranchia" (= Allogastropoda)

2010 taxonomy

Jörger et al. (2010) have redefined major groups within the Heterobranchia: they moved

and

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 ...

.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 ...

'' 10: 323. .

2014 taxonomy

Wägele et al. (2014):Wägele H., Klussmann-Kolb A., Verbeek E. & Schrödl M. (2014). "Flashback and foreshadowing—a review of the taxon Opisthobranchia". ''

Organisms Diversity & Evolution In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; ...

'' 14(1): 133–149. moved Rissoelloidea and

from Lower Heterobranchia to

Euthyneura Euthyneura is a taxonomic infraclass of snails and slugs, which includes species exclusively from marine, aquatic and terrestrial gastropod mollusks in the clade Heterobranchia. Euthyneura are characterised by several autapomorphies, but ar ...

2016 taxonomy

Kano et al. (2016): moved Ringiculoidea from Lower Heterobranchia to

. So the following taxa remain within the Lower Heterobranchia: *Unassigned to a superfamily (orbitestellid-shells) ** Family

* superfamily Omalogyroidea * † superfamily Streptacidoidea * superfamily Valvatoidea

References

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