Systellommatophora
Clade of gastropods
From Wikipedia, the free encyclopedia
The Systellommatophora (synonym Gymnomorpha) is a clade of primitive, air-breathing slugs, according to the taxonomy of the Gastropoda (Bouchet & Rocroi, 2005).[1]
| Systellommatophora | |
|---|---|
| |
| Land slug Laevicaulis alte (Veronicelloidea) | |
 | |
| Sea slug Onchidella sp. (Onchidioidea) | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Superorder: | Eupulmonata |
| Order: | Systellommatophora |
| Families | |
|
See text | |
| Synonyms | |
|
Gymnomorpha | |
They are marine and terrestrial pulmonate gastropods within the Heterobranchia. There are two superfamilies in this clade. Slugs in the superfamily Onchidioidea are primarily marine (except for five land-dwelling or freshwater species),[2] whereas slugs in the superfamily Veronicelloidea are primarily terrestrial.
Anatomy
No species in this clade has a shell as an adult.[2][3] These slugs are distinguished by the location of the anus at the rear of the body.[4]
Although neither superfamily bears shells as adults,[3] the Onchidioidea do possess a vestigial, non-mineralized shell sac[5] and possess a larval shell.[6] It is not known whether or not the veronicellids bear a larval shell.[7]
Taxonomy
According to the previous taxonomy of the Gastropoda (Ponder & Lindberg, 1997) Systellommatophora was considered to be a suborder or an order.[8]
The following two superfamilies and families have been recognized in the taxonomy of Bouchet & Rocroi (2005):
- superfamily Onchidioidea Rafinesque, 1815
- Onchidiidae Rafinesque, 1815
- Superfamily Veronicelloidea Gray, 1840
- Veronicellidae Gray, 1840
- Rathouisiidae Heude, 1885