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The families included in this recently established superorder of molluscs<ref>{{cite journal | quotes=no | author = Haszprunar G. |title = The Heterobranchia ― a new concept of the phylogeny of the higher Gastropoda|year = 1985| journal = Zeitschrift für zoologische Systematik und Evolutionsforschung|volume = 23| issue = 1 | pages = 15–37}} ISSN 0044-3808</ref> have historically been placed in many different parts of the taxonomic class of gastropods. Earlier authors (as [[John Edward Gray|J.E. Gray]], 1840) placed the Heterobranchia as a borderline category intermediate between the [[Opisthobranchia]] & [[Pulmonata]], and all the other gastropods.
The families included in this recently established superorder of molluscs<ref>{{cite journal | quotes=no | author = Haszprunar G. |title = The Heterobranchia ― a new concept of the phylogeny of the higher Gastropoda|year = 1985| journal = Zeitschrift für zoologische Systematik und Evolutionsforschung|volume = 23| issue = 1 | pages = 15–37}} ISSN 0044-3808</ref> have historically been placed in many different parts of the taxonomic class of gastropods. Earlier authors (as [[John Edward Gray|J.E. Gray]], 1840) placed the Heterobranchia as a borderline category intermediate between the [[Opisthobranchia]] & [[Pulmonata]], and all the other gastropods.


The (sometimes recognized) order [[Heterostropha]] within the Heterobranchia, which includes such families as ''[[Architectonicidae]]'', the sundial or staircase snails, is primarily characterized by a shell which has a heterostrophic [[protoconch]], in other words the apical whorls are coiled in the opposite plane to the adult whorls. The classification of this group has been revised by Ponder & Warén (1988)<ref>{{cite journal | quotes=no | author = Ponder, W. F. & Warén, A. |title = Classification of the Caenogastropoda and Heterostropha- A list of family-group names and higher taxa|year = 1988| journal = Malacological review supplement |volume = 4| issue =| pages = 288–317}}</ref>.
The (sometimes recognized) order [[Heterostropha]] within the Heterobranchia, which includes such families as ''[[Architectonicidae]]'', the sundial or staircase snails, is primarily characterized by a shell which has a heterostrophic [[protoconch]], in other words the apical whorls are coiled in the opposite plane to the adult whorls. The classification of this group has been revised by [[Winston Ponder|Ponder]] & Warén (1988)<ref>{{cite journal | quotes=no | author = Ponder, W. F. & Warén, A. |title = Classification of the Caenogastropoda and Heterostropha- A list of family-group names and higher taxa|year = 1988| journal = Malacological review supplement |volume = 4| issue =| pages = 288–317}}</ref>.


(In contrast to the heterobranchs, the bodies of the Opisthobranchia have undergone detorsion (unwinding). They have essentially evolved back to the bilateral symmetry of their ancestors. The mantle cavity of the Pulmonata has modified into an air-breathing organ. They are also characterized by detorsion and a symmetrically-arranged nervous system. The pulmonates usually lack an [[Operculum (gastropod)|operculum]] and are [[hermaphroditic]]. The order Pulmonata contains most land snails and slugs, many freshwater snails, and a small number of marine species.)
(In contrast to the heterobranchs, the bodies of the Opisthobranchia have undergone detorsion (unwinding). They have essentially evolved back to the bilateral symmetry of their ancestors. The mantle cavity of the Pulmonata has modified into an air-breathing organ. They are also characterized by detorsion and a symmetrically-arranged nervous system. The pulmonates usually lack an [[Operculum (gastropod)|operculum]] and are [[hermaphroditic]]. The order Pulmonata contains most land snails and slugs, many freshwater snails, and a small number of marine species.)
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***Superfamily [[Amphiboloidea]] <small>J.E. Gray, 1840</small>
***Superfamily [[Amphiboloidea]] <small>J.E. Gray, 1840</small>
***Superfamily [[Chilinoidea]] <small>H. & [[Arthur Adams (zoologist)|A. Adams]], 1855</small>
***Superfamily [[Chilinoidea]] <small>H. & [[Arthur Adams (zoologist)|A. Adams]], 1855</small>
***Superfamily [[Glacidorboidea]] <small>Ponder, 1986</small>
***Superfamily [[Glacidorboidea]] <small>[[Winston Ponder|Ponder]], 1986</small>
***Superfamily [[Lymnaeoidea]] <small>[[Rafinesque]], 1815</small>
***Superfamily [[Lymnaeoidea]] <small>[[Rafinesque]], 1815</small>
***Superfamily [[Planorboidea]] <small>[[Rafinesque]], 1815</small>
***Superfamily [[Planorboidea]] <small>[[Rafinesque]], 1815</small>

Revision as of 20:16, 28 February 2009

Heterobranchia
The sea butterfly or pteropod gastropod, Clione limacina
Scientific classification
Kingdom:
Animalia
Phylum:
Mollusca
Class:
Gastropoda
Subclass:
Orthogastropoda
Infraclass:
Apogastropoda
Superorder:
Heterobranchia
Orders

Heterostropha
Opisthobranchia
Pulmonata

Heterobranchia, the heterobranchs, (meaning "different-gilled snails"), is a taxonomic superorder of sea snails, marine gastropod molluscs.

(Note: Gastropod taxonomy has been in flux for many years, and this is especially true currently, because of new research in molecular phylogeny. Because of all this on-going change, different reliable sources can yield very different classifications. This is especially true within groups which are poorly understood in general.)

This superorder contains a diverse and interesting group of families. The similarity in the structure of the gills within this group makes the various families eligible for membership, despite all the other differences they show.

The families included in this recently established superorder of molluscs[1] have historically been placed in many different parts of the taxonomic class of gastropods. Earlier authors (as J.E. Gray, 1840) placed the Heterobranchia as a borderline category intermediate between the Opisthobranchia & Pulmonata, and all the other gastropods.

The (sometimes recognized) order Heterostropha within the Heterobranchia, which includes such families as Architectonicidae, the sundial or staircase snails, is primarily characterized by a shell which has a heterostrophic protoconch, in other words the apical whorls are coiled in the opposite plane to the adult whorls. The classification of this group has been revised by Ponder & Warén (1988)[2].

(In contrast to the heterobranchs, the bodies of the Opisthobranchia have undergone detorsion (unwinding). They have essentially evolved back to the bilateral symmetry of their ancestors. The mantle cavity of the Pulmonata has modified into an air-breathing organ. They are also characterized by detorsion and a symmetrically-arranged nervous system. The pulmonates usually lack an operculum and are hermaphroditic. The order Pulmonata contains most land snails and slugs, many freshwater snails, and a small number of marine species.)

Taxonomy of the Heterobranchia

Superorder Heterobranchia J.E. Gray, 1840

References

  1. ^ Haszprunar G. (1985). "The Heterobranchia ― a new concept of the phylogeny of the higher Gastropoda". Zeitschrift für zoologische Systematik und Evolutionsforschung. 23 (1): 15–37. {{cite journal}}: Unknown parameter |quotes= ignored (help) ISSN 0044-3808
  2. ^ Ponder, W. F. & Warén, A. (1988). "Classification of the Caenogastropoda and Heterostropha- A list of family-group names and higher taxa". Malacological review supplement. 4: 288–317. {{cite journal}}: Unknown parameter |quotes= ignored (help)CS1 maint: multiple names: authors list (link)
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