Tomichia is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of very small freshwater snail

Freshwater snail

A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....

s which have a gill

Gill

A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...

 and an operculum

Operculum (gastropod)

The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...

, gastropod mollusks or micromollusk

Micromollusk

A micromollusk is a descriptive term for a shelled mollusk which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine mollusks, although in addition, numerous species of land snails and freshwater mollusks also reach adult size at very small...

s in the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Pomatiopsidae

Pomatiopsidae

Pomatiopsidae is a family of small mainly freshwater snails with gills and an operculum, aquatic gastropod mollusks in the superfamily Rissooidea ....

.

Distribution

Distribution of genus Tomichia include South Africa and in Eastern Zaire. Tomichia is the only genus of Pomatiopsidae in Africa.

Ecology

This genus is freshwater and brackish. There exist halophilic species of Tomichia in saline lakes such as Tomichia ventricosa.

Species

Brown (1994) recognized 10 species (7 in South Africa and 3 in Central Africa) and one undescribed species. Kameda & Kato (2011) recognized 11 species of Tomichia.

Species within the genus Tomichia include:

• Tomichia cawstoni Connolly, 1939
• Tomichia differens Connolly, 1939
• Tomichia guillemei Leloup, 1953
• Tomichia hendrickxi (Verdcourt, 1950)
• Tomichia kivuensis Mandahl-Barth, 1974
• Tomichia natalensis Connolly, 1939
• Tomichia rogersi (Connolly, 1929)
• Tomichia tristis
  Tomichia tristis
  Tomichia tristis is a species of very small freshwater or brackish snail with a gill and an operculum, gastropod mollusk or micromollusk in the family Pomatiopsidae.-Distribution:Eastern Cape Province, South Africa....
  
  (Morelet, 1889) - critically endangered
• Tomichia ventricosa (Reeve, 1842) - type species
• Tomichia zwellendamensis (Küster, 1852)
• (?)Tomichia n.sp. - reported by Cohen (1986) from Lake Turkana
  Lake Turkana
  Lake Turkana , formerly known as Lake Rudolf, is a lake in the Great Rift Valley in Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake...
  
  

External links

• Davis G. M. (1981). "Different Modes of Evolution and Adaptive Radiation in the Pomatiopsidae (Prosobranchia: Mesogastropoda)". Malacologia
  Malacologia
  Malacologia is a peer-reviewed scientific journal in the field of malacology, the study of mollusks. The journal publishes articles in the fields of molluscan systematics, ecology, population ecology, genetics, molecular genetics, evolution, and phylogenetics.The journal specializes in publishing...
  
  21(1-2): 209-262.
• Verdcourt B. (1951). "The distribution of the genus Tomichia Benson in Africa". Revue de Zoologie et de Botanique Africaines 44: 173-174.
• Verdcourt B. (1960). "A further collection of Tomichia hendrickxi (Verdcourt) from the Belgian Congo". Basteria 24: 3.