Kenkiidae is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of freshwater

triclad A planarian is one of the many flatworms of the traditional class (biology), class Turbellaria. It usually describes free-living flatworms of the order Tricladida (triclads), although this common name is also used for a wide number of free-li ...

s. Their species can be found sporadically in caves, groundwater, and deep lakes in

Central Asia Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...

Far East The ''Far East'' was a European term to refer to the geographical regions that includes East and Southeast Asia as well as the Russian Far East to a lesser extent. South Asia is sometimes also included for economic and cultural reasons. The ter ...

and

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

.Ball, I. R.: A contribution to the phylogeny and biogeography of the freshwater triclads (Platyhelminthes: Turbellaria). Biology of the Turbellaria (Edited by: Riser NW and Morse MP). New York: McGraw-Hill New York 1974 , 339-401.

Description

Species in the family Kenkiidae are characterized by a thickened marginal epidermis, i.e., the epidermis of the body margins have larger cells provided with bigger

rhabdite Rhabdites (from Greek, ''rhabdos'', rod) are rodlike structures in the cells of the epidermis or underlying parenchyma in certain turbellarians, and in the epidermis of nemertea Nemertea is a phylum of animals also known as ribbon worms or p ...

s than the epidermis of the rest of the body. Kenkiidae species have the testicles situated anterior to the pharynx, feature also common in the

Dugesiidae Dugesiidae is a family of freshwater planarians distributed worldwide (except Antarctica). The type genus is ''Dugesia'' Girard, 1850.Ball, I. R.: A contribution to the phylogeny and biogeography of the freshwater triclads (Platyhelminthes: Tur ...

and

Planariidae Planariidae is a family (biology), family of freshwater Tricladida, planarians. The type genus is ''Planaria'' Müller, 1776.Ball IR: A contribution to the phylogeny and biogeography of the freshwater triclads (Platyhelminthes: Turbellaria). Bi ...

. They have an anterior adhesive organ, which is also found in the family

Dendrocoelidae Dendrocoelidae is a family of freshwater tricladida flatworms that has a holarctic distribution. The largest freshwater triclad known belongs to this family, it's up to 40 cm in length and inhabits the Lake Baikal. Description The famil ...

. The inner muscles of the pharynx are divided in two layers. Kenkiidae species are not pigmented and they are usually blind.

Phylogeny

Kenkiidae is the sister group of the family Dendrocoelidae. Both families have an apomorphic anterior adhesive organ. Phylogenetic supertree after Sluys et al., 2009:

References

External links

{{Taxonbar, from=Q3195150 Continenticola Platyhelminthes families