True frog
True frogs inhabit every continent except Antarctica. Their range stretches from North America to northern South America, across Europe and Africa including Madagascar, and throughout Asia. The Asian population extends into the East Indies and reaches New Guinea. A single species known as the Australian wood frog has spread into the far north of Australia. This family holds the widest distribution of any frog group on Earth. They thrive in diverse environments ranging from aquatic habitats to brackish water zones. Some true frogs live close to water while others occupy arboreal spaces. Most species lay eggs directly in water and undergo a tadpole stage before maturing.
Typically true frogs possess smooth moist skin paired with large powerful legs. Extensively webbed feet allow for efficient swimming capabilities. Size variations span from small specimens like the wood frog to much larger individuals. Many members of this family are aquatic or live near water sources. Arboreal species exist within the group alongside terrestrial dwellers. The family includes some of the very few amphibians capable of living in brackish water. These physical traits support their cosmopolitan lifestyle across varied global climates. Smooth skin facilitates moisture retention while strong legs enable rapid movement through water or onto land.
Ranidae diverged from Indian-endemic Nyctibatrachidae during the early Eocene epoch. Other studies suggest a closer relationship with Dicroglossidae instead. The family began dispersing out of Asia at the end of the Eocene period. By the beginning of the Miocene they had colonized every continent except Antarctica. Scientists previously believed Ranidae evolved on Insular India during the Cretaceous period. This theory held that India remained isolated until its collision with Asia in the late Eocene. That event allowed Ranidae to spread into Eurasia and eventually reach the rest of the world. Recent research proposes an alternative origin story placing the family's roots in Eurasia rather than Gondwana. Close relationships between lineages may result from those groups colonizing India from Eurasia during the Paleogene era.
Subdivisions within the Ranidae remain a matter of scientific dispute despite growing consensus. Several former subfamilies now stand as separate families including Petropedetidae Cacosterninae Mantellidae and Dicroglossidae. The genus Rana has been split up and is significantly reduced in size compared to historical classifications. As of mid-2008 ongoing studies continue to clarify lineage boundaries. Staurois represents a very ancient offshoot of the main Raninae lineage. Amolops forms a generally delimited monophyletic group. Odorrana combined with Rana plus some proposed minor genera constitute another distinct cluster. A specific grouping includes Clinotarsus Huia in the strict sense and Meristogenys. An ill-defined assemblage contains Babina Glandirana Hylarana Pulchrana Sanguirana Sylvirana Hydrophylax and Pelophylax. Some authorities treat these names as junior synonyms of the genus Hylarana.
Most subfamilies formerly included under Ranidae are now treated as separate families leaving only Raninae remaining. Current recognized genera include Abavorana Oliver Prendini Kraus and Raxworthy 2015 containing three species. Amnirana Dubois 1992 holds eleven species while Amolops Cope 1865 maintains eighty species. Babina Thompson 1912 lists two species and Chalcorana Dubois 1992 contains nine species. Clinotarsus Mivart 1869 has three species and Glandirana Fei Ye and Huang 1990 has six species. Huia Yang 1991 remains monotypic with a single species. Humerana Dubois 1992 possesses four species and Hydrophylax Fitzinger 1843 also has four species. Hylarana Tschudi 1838 includes four species and Indosylvirana Oliver Prendini Kraus and Raxworthy 2015 contains thirteen species. Lithobates Fitzinger 1843 holds fifty-five species while Meristogenys Yang 1991 has thirteen species. Nidirana Dubois 1992 contains nineteen species and Odorrana Fei Ye and Huang 1990 has sixty-four species. Papurana Dubois 1992 lists nineteen species and Pelophylax Fitzinger 1843 has nineteen species. Pseudorana Fei Ye and Huang 1990 is monotypic and Pterorana Kiyasetuo and Khare 1986 is also monotypic. Pulchrana Dubois 1992 contains eighteen species and Rana Linnaeus 1758 has fifty-eight species. Sanguirana Dubois 1992 lists six species and Staurois Cope 1865 has six species. Sumaterana Arifin Smart Hertwig Smith Iskandar and Haas 2018 contains three species. Sylvirana Dubois 1992 has twelve species and Wijayarana Arifin Chan Smart Hertwig Smith Iskandar and Haas 2021 includes five species. In 2023 Amphibian Species of the World tentatively synonymized Amnirana Chalcorana Humerana Hydrophylax Indosylvirana Papurana Pulchrana and Sylvirana into Hylarana until significant taxonomic confusion surrounding the group could be cleared up. These changes are not recognized by AmphibiaWeb.
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Common questions
Where do true frogs live and which continent is excluded from their range?
True frogs inhabit every continent except Antarctica. Their distribution spans North America, South America, Europe, Africa including Madagascar, Asia, the East Indies, New Guinea, and northern Australia.
What physical characteristics distinguish true frogs from other amphibians?
Typically true frogs possess smooth moist skin paired with large powerful legs. Extensively webbed feet allow for efficient swimming capabilities while some species can live in brackish water zones.
When did the Ranidae family diverge and disperse across continents?
Ranidae diverged from Indian-endemic Nyctibatrachidae during the early Eocene epoch. The family began dispersing out of Asia at the end of the Eocene period and had colonized every continent except Antarctica by the beginning of the Miocene.
How has taxonomic classification of true frogs changed since 2008?
As of mid-2008 ongoing studies continue to clarify lineage boundaries after several former subfamilies became separate families. In 2023 Amphibian Species of the World tentatively synonymized Amnirana Chalcorana Humerana Hydrophylax Indosylvirana Papurana Pulchrana and Sylvirana into Hylarana until significant taxonomic confusion surrounding the group could be cleared up.
Which genera within the true frog family contain the highest number of species?
Odorrana Fei Ye and Huang 1990 has sixty-four species while Lithobates Fitzinger 1843 holds fifty-five species. Rana Linnaeus 1758 has fifty-eight species and Amolops Cope 1865 maintains eighty species.
All sources
11 references cited across the entry
- 1journalPhylogenomics reveals rapid, simultaneous diversification of three major clades of Gondwanan frogs at the Cretaceous–Paleogene boundaryYan-Jie Feng et al. — 2017-07-18
- 2journalPhylogeny and Biogeography of a Cosmopolitan Frog Radiation: Late Cretaceous Diversification Resulted in Continent-Scale Endemism in the Family RanidaeFranky Bossuyt et al. — 2006-08-01
- 3journalDispersal vs. vicariance: the origin of India's extant tetrapod faunaK. Praveen Karanth — 2021
- 4webHylarana Tschudi, 1838Amphibian Species of the World 5.5, an Online Reference — American Museum of Natural History
- 5journalPhylogeny of Raninae (Anura: Ranidae) inferred from mitochondrial and nuclear sequencesJing Che et al. — 2007-04-01
- 6webRanidae Batsch, 1796 Amphibian Species of the World2023-05-28