Trionychia is a superfamily of turtle

Turtle

Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...

s which encompasses the species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 that are commonly referred to as softshelled turtles as well as some others. They are found throughout the temperate regions of the world.

It traditionally consisted of a single 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...

, two subfamilies, and 14 genera

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...

. However, more recently it was realized that the supposed "Kinosternoidea

Kinosternoidea

Kinosternoidea is a superfamily of aquatic turtles, which included two families: Dermatemydidae, and Kinosternidae.These are nowadays usually considered independent families of the Trionychia, among which they represent very plesiomorphic members which share a few peculiarly advanced traits...

" are actually early offshoots of the Trionychoidea and not as closely related among each other as it was believed. These two families lack the characteristic trionychoid apomorphies, but possess some highly derived characters of their own, which they moreover evolved independently from each other.

Systematics

Except for those not assigned to a family, only living genera are listed here.

Basal and incertae sedis

Incertae sedis

, is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

• Genus †Hoplochelys (fossil
  Fossil
  Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
  
  )
• Genus †Emarginachelys
  Emarginachelys
  Emarginachelys cretacea is the earliest described chelydrid, known from well preserved fossils from the Maastrichtian stage of the Late Cretaceous of Montana....
  
  (fossil)

Family †Adocidae (fossil)

• Subfamily Shachemydinae
  • Genus Shachemys

Family Carettochelyidae

• Subfamily Carettochelyinae
  • Genus Carettochelys

Family Trionychidae

Trionychidae

Trionychidae is a taxonomic family which comprises a number of turtle genera commonly known as softshells. They are also sometimes called pancake turtles. Softshells consist of some of the world's largest fresh water turtles, though many can adapt to living in highly brackish areas. Members of this...

• Subfamily Plastomeninae  (fossil)
• Subfamily Cyclanorbinae
  Cyclanorbinae
  Cyclanorbinae is a subfamily of flapshell turtles in the Trionychidae family....
  
  
  • Genus Cyclanorbis
    Cyclanorbis
    Cyclanorbis is a genus of softshell turtle in the Trionychidae family.It contains the following species:* Nubian flapshell turtle * Senegal flapshell turtle...
    
    
  • Genus Cycloderma
    Cycloderma
    Cycloderma is a genus of softshell turtle in the Trionychidae family.It contains the following two species:* Aubry's flapshell turtle - Cycloderma aubryi * Zambezi flapshell turtle - Cycloderma frenatum...
    
    
  • Genus Lissemys
    Lissemys
    Lissemys is a genus of turtles of the family Trionychidae. It contains two species.-Species:* Lissemys punctata * Lissemys scutata...
    
    
• Subfamily Trionychinae
  Trionychinae
  Trionychinae is a subfamily of turtles in the Trionychidae family.- Classification :10 Genera :*Amyda*Apalone*Chitra*Dogania*Nilssonia*Palea*Pelochelys*Pelodiscus*Rafetus*Trionyx...
  
  
  • Genus Amyda
    Amyda
    Amyda is a genus of softshell turtle in the Trionychidae family.It contains the following species:* Asiatic Softshell Turtle * Amyda nakornsrithammarajensis...
    
    
  • Genus Apalone
    Apalone
    Apalone is a North American genus in the Trionychidae family of turtles, a family whose members are commonly referred to as softshell turtles. Apalone species are native primarily to the United States, though they are also found in parts of southern Canada and northern Mexico...
    
    
  • Genus Chitra
    Chitra (genus)
    Chitra is a genus of turtles of the family Trionychidae.-Species:*Chitra chitra *Chitra chitra chitra...
    
    
  • Genus Dogania
    Dogania
    Dogania is a genus of softshell turtle in the Trionychidae family.It contains the following species:* Malayan Soft-Shelled Turtle -References:* Alderton, D. 1988. Turtles and tortoises of the world. Facts on File, New York....
    
    
  • Genus Nilssonia
  • Genus Palea (genus)
  • Genus Pelochelys
    Pelochelys
    Pelochelys is a genus of turtles of the family Trionychidae.-Species:* New Guinea giant softshell turtle - Pelochelys bibroni* Cantor's giant softshell turtle- Pelochelys cantorii...
    
    
  • Genus Pelodiscus
    Pelodiscus
    Pelodiscus is a turtle genus in the family Trionychidae.-Species:* Chinese softshell turtle * Hunan softshell turtle * Lesser Chinese softshell turtle...
    
    
  • Genus Rafetus
    Rafetus
    Rafetus is a genus of highly endangered softshell turtles in the Trionychidae family. According to most taxonomists, it contains the following 2 species:* Euphrates softshell turtle...
    
    
  • Genus Trionyx

External links

(2008): Mikko's Phylogeny Archive

Mikko's Phylogeny Archive

Mikko's Phylogeny Archive is an amateur paleontology website maintained by Mikko Haaramo, a student at the University of Helsinki's Department of Geology, Division of Geology and Palaeontology....

- Trionychoidea. Version of 2008-MAR-11. Retrieved 2008-MAY-06.