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Short description: Clade of gastropods

Land slug Laevicaulis alte (Veronicelloidea)
Sea slug Onchidella sp. (Onchidioidea)
Scientific classification e
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Heterobranchia
Superorder: Eupulmonata
Order: Systellommatophora

See text



The Systellommatophora (synonym Gymnomorpha) is a clade of primitive, air-breathing slugs, according to the taxonomy of the Gastropoda (Bouchet & Rocroi, 2005).[1]

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.


No species in this clade have shells as adults.[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]


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):


  1. MolluscaBase eds. (2020). MolluscaBase. Stylommatophora. Accessed through: World Register of Marine Species at: on 2020-05-02
  2. 2.0 2.1 Dayrat B. (2009). "Review of the current knowledge of the systematics of Onchidiidae (Mollusca: Gastropoda: Pulmonata) with a checklist of nominal species" (preview). Zootaxa 2068: 1–26. doi:10.11646/zootaxa.2068.1.1. 
  3. 3.0 3.1 Schilthuizen M.; Thome J. W. (2008). "Valiguna flava (Heynemann, 1885) from Indonesia and Malaysia: Redescription and Comparison with Valiguna siamensis (Martens, 1867) (Gastropoda: Soleolifera: Veronicellidae)". Veliger 50 (3): 163–170. 
  4. Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 377. ISBN 0-03-056747-5. 
  5. TILLIER, S (1983). "A new mountain Platevindex from Philippine Islands (Pulmonata: Onchidiidae)". Journal of Molluscan Studies (Malacological Soc London) 49 (supp12A): 198. 
  6. Morton, Brian (1992). The Marine Flora and Fauna of Hong Kong and Southern China III___ Fouling and pollution, morphology, behaviour and physiology, Hoi Ha Wan. Hong Kong University Press. ISBN 978-962-209-295-2. 
  7. Dayrat, B.; Tillier, S. (2002). "Evolutionary relationships of euthyneuran gastropods (Mollusca): a cladistic re-evaluation of morphological characters". Zoological Journal of the Linnean Society 135 (4): 403. doi:10.1046/j.1096-3642.2002.00018.x. 
  8. "Systellommatophora". Integrated Taxonomic Information System. 

Wikidata ☰ Q1319200 entry