Most species in this family are part of the subfamily Kneriinae; they typically live in fast-flowing streams, often in highlands, and are small fish, no more than 15 cm (5.9 in) in length. The second subfamily Phractolaeminae contains only a singe species, which typically inhabits stagnant or slow-moving waters and reaches up to 25 cm (9.8 in) in length. All Kneriidae have an elongated body shape. Some species are sexually dimorphic, with the male possessing a rosette on the gill covers that is absent in the females. Other species are neotenic, retaining larval features into adulthood.[1]
There are about 31 extant (living) species in five genera.[2] There are two subfamilies, but Phractolaeminae has commonly been regarded as a full family (in which case there is no need for recognizing Kneriinae as it would contain all four remaining genera in Kneriidae).[3][4]
In addition, the family includes the genus Mahengichthys, which only is known from Eocenefossil remains and is closer to Kneriinae than Phractolaeminae.[4][5]
^Banister, Keith F. (1998). Paxton, J.R.; Eschmeyer, W.N. (eds.). Encyclopedia of Fishes. San Diego: Academic Press. p. 97. ISBN0-12-547665-5.
^Froese, Rainer, and Daniel Pauly, eds. (2021). "Kneriidae"inFishBase. July 2021 version.
^Eschmeyer, W.N.; Grande, T.; Grande, L. (2010). "A Nomenclatural Analysis of Gonorynchiform Taxa". Gonorynchiformes and Ostariophysan Relationships. pp. 567–587. doi:10.1201/b10194-14.
^ abNear, T.J.; Dornburg, A.; Friedman, M. (2014). "Phylogenetic relationships and timing of diversification in gonorynchiform fishes inferred using nuclear gene DNA sequences (Teleostei: Ostariophysi)". Molecular Phylogenetics and Evolution. 80: 297–307. doi:10.1016/j.ympev.2014.07.013.
^Davis, M.P.; Arratia, G.; Kaiser, T.M. (2013). "The first fossil shellear (Gonorynchiformes: Kneriidae) from the Eocene lake of Mahenge (Tanzania)". Mesozoic Fishes 5 - Global Diversity and Evolution. pp. 325–362. ISBN978-3-89937-159-8.
