The Pipidae are a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of primitive,

tongue The tongue is a Muscle, muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for chewing and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper s ...

less

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

s. There are 41 species in the family, found in tropical

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

(genus ''Pipa'') and sub-Saharan

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

(the three other genera).

Description

Pipid frogs are highly aquatic and have numerous morphological modifications befitting their habitat. For example, the feet are completely webbed, the body is flattened, and a

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

system is present in adults. In addition, pipids possess highly modified ears for producing and receiving sound under water. They lack a tongue or vocal cords, instead having bony rods in the larynx that help produce sound. They range from in body length.

Taxonomy

Morphological data suggest that ''

Xenopus ''Xenopus'' () (Gk., ξενος, ''xenos'' = strange, πους, ''pous'' = foot, commonly known as the clawed frog) is a genus of highly aquatic frogs native to sub-Saharan Africa. Twenty species are currently described with ...

'' is the sister-group of all other pipids, whereas molecular data consistently suggest that ''

Pipa The pipa, pípá, or p'i-p'a () is a traditional Chinese musical instrument belonging to the plucked category of instruments. Sometimes called the "Chinese lute", the instrument has a pear-shaped wooden body with a varying number of frets rangi ...

'' is the sister-group of other pipids. Family Pipidae * '' Hymenochirus'' - dwarf clawed frogs (4 species) * ''

'' - Surinam toads (7 species) * ''

Pseudhymenochirus Merlin's dwarf gray frog (''Pseudhymenochirus merlini''), or Merlin's clawed frog, is a species of frog in the family Pipidae. It is monotypic within the genus ''Pseudhymenochirus''. It is found in southern Guinea-Bissau, western Guinea, and sout ...

'' - Merlin's dwarf gray frog or Merlin's clawed frog (1 species) * ''

'' - clawed frogs (29 species) ** Subgenus ''(

Silurana ''Silurana'' is a subgenus of frogs in the family Pipidae. They are closely related the clawed frog subgenus, ''Xenopus ''Xenopus'' () (Gk., ξενος, ''xenos'' = strange, πους, ''pous'' = foot, commonly known as the ...

)'' - common clawed frogs ** Subgenus ''(

)'' - tropical clawed frogs

Fossil record

The oldest fossil records of frogs more closely related to pipid frogs than to other extant frog families (

Pipimorpha Pipoidea are a clade of frogs, that contains the most recent common ancestor of living Pipidae and Rhinophrynidae as well as all its descendants. It is broadly equivalent to Xenoanura. Description The synapomorphies that define Pipoidea are ...

) extends into the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

. The oldest known

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor ...

pipids are '' Oumtkoutia'' and ''

Pachycentrata ''Pachycentrata'' is an extinct genus of frogs. ''Pachycentrata'' fossils have been found in the In Beceten Formation located in Tahoua, Niger. A. M. Báez and J.-C. Rage. 1998. Pipid frogs from the Upper Cretaceous of In Beceten, Niger. Palaeo ...

'' from the Upper Cretaceous of Morocco and Niger, respectively. Included taxa after A. M. Aranciaga Rolando et al. 2019 * †'' Oumtkoutia'' (Rage and Dutheil 2008) Aoufous Formation, Morocco, Late Cretaceous (

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

) * †''

Llankibatrachus ''Llankibatrachus'' is an extinct genus of prehistoric frogs in the family Pipidae. They are known from the Ypresian ( Casamayoran) Huitrera Formation of Argentina. Description The type species and the only known species, ''Llankibatrachus tr ...

'' (Báez and Pugener 2003) Huitrera Formation, Argentina,

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

* †''

'' (Báez and Rage 2004) (= ''Pachybatrachus'' Báez and Rage, 1998)

In Beceten Formation The In Beceten Formation, also Beceten or Ibecten is a Coniacian to Santonian geologic formation in the Iullemmeden Basin of Niger. It has yielded a diverse fauna and some angiosperms. Among others, it has yielded polypterifoms, urodeles, anura ...

, Niger, Late Cretaceous ( Coniacian) * †"''

Shelania ''Shelania'' is an extinct genus of frogs that lived in South America during the Eocene. Its type species is ''Shelania pascuali''. Fossils of ''Shelania'' have been found in the Mustersan Vaca Mahuida and Laguna del Hunco Formations of Argent ...

" laurenti'' (Baez and Pugener 1998) Argentina, Eocene * ''"Xenopus" romeri'' (Estes 1975) Companhia National de Cimento Portland Quarry, Brazil,

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

* †'' Eoxenopoides'' (Haughton 1931) South Africa, Late Cretaceous (

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

) * †''

Singidella ''Singidella'' is an extinct genus of prehistoric frog from the Eocene of Tanzania. There is currently only one described species, ''S. latecostata''. Its generic name is derived from Singida, the city near which the only known specimens were fo ...

'' (Báez and Harrison 2005) Tanzania, Eocene * †

Saltenia ''Saltenia'' is an extinct genus of frogs. It was assigned to the family Pipidae by R. L. Carroll in 1988 and again in 2005 by A. M. Báez and T. Harrison. The single described species, ''Saltenia ibanezi'', is thought to have lived in South Ame ...

(Reih 1959) Las Curtiembres Formation, Argentina, Late Cretaceous (

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

) However, a more recent analysis suggests that some of these taxa are only close relatives of Pipidae, but outside the crown-group. Furthermore, the composition of this crown clade (in terms of which extinct taxa are included) depends on whether or not the topology is constrained to reflect the molecular tree.

References

Bibliography

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External links

* * {{Authority control Amphibian families Mesobatrachia Taxa named by John Edward Gray Extant Berriasian first appearances