Alona is a genus of cladocera

Cladocera

Cladocera is an order of small crustaceans commonly called water fleas. Around 620 species have been recognised so far, with many more undescribed. They are ubiquitous in inland aquatic habitats, but rare in the oceans. Most are long, with a down-turned head, and a carapace covering the apparently...

ns in the family Chydoridae. It is one of the largest genera of Cladocera, and is widely believed to be an artificial group which is in need of systematic revision; the type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 is Alona quadrangularis. Around 240 names at the species level have been described in Alona; it is unclear how many of these are valid, or how they are related.
Species currently assigned to the genus Alona include:

• Alona hercegovinae
  Alona hercegovinae
  Alona hercegovinae is a species of crustacean in family Chydoridae. It is endemic to Bosnia and Herzegovina. Its natural habitat is inland karsts.-References:* Sket, B. 1996. . Downloaded on 9 August 2007....
  
  Brancelj, 1990
• Alona quadrangularis (O. F. Müller, 1776)
• Alona sketi
  Alona sketi
  Alona sketi is a species of crustacean in family Chydoridae. It is endemic to Slovenia. Its natural habitat is inland karsts....
  
  Brancelj, 1992
• Alona smirnovi
  Alona smirnovi
  Alona smirnovi is a species of crustacean in family Chydoridae. It is endemic to the Republic of Macedonia. Its natural habitat is inland karsts.-References:* Sket, B. 1996. . Downloaded on 9 August 2007....
  
  Petkovsky & Flossner,1972