Heterobranchia
The Heterobranchs are a large group of snails and slugs. The group includes marine, aquatic and terrestrial gastropod molluscs.
| Heterobranchia | |
|---|---|
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| Four examples of Heterobranchia | |
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Heterobranchia J.E. Gray, 1840 |
| Taxonomic subcategories | |
|
informal group Lower Heterobranchia | |
Heterobranchia is one of the main clades of gastropods. It has three informal groups: [1] The details are extremely complicated, and not yet quite worked out. Experts say they have "poorly resolved phylogenetic relationships".[2]
- Lower Heterobranchia: a group of rather specialized, highly evolved sea slugs and sea snails.
- Opisthobranchia: almost all are marine species, some shelled and some not. They are a group of slugs and snails with grinding gizzard plates.
- Pulmonata. This is a group which is familiar to most people. It includes most land snails and slugs, many freshwater snails and a few marine species. They breathe air, are hermaphrodite, and usually have no operculum.[3]
Heterobranchia Media
A shell of the marine species Bulla quoyii, which is an opisthobranch.
The graph of neighbor-joining phylogenetic tree shows that there is no clade-supporting pattern for the monophyly of Opisthobranchia (green) or of Pulmonata (yellow) based on datasets by Jörger et al. (2010).
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References
- ↑ Bouchet P. & Rocroi J.-P. (eds) 2005. Classification and nomenclator of gastropod families. Malacologia: International Journal of Malacology. 47(1-2). [1]
- ↑ Dinapoli A. & Klussmann-Kolb A. 2010. The long way to diversity – phylogeny and evolution of the Heterobranchia (Mollusca: Gastropoda). Molecular Phylogenetics and Evolution 55 (1): 60–76. [2]
- ↑ The operculum is the hard section on the foot which closes up the shell so the animal is safe inside.