''Pseudis paradoxa'', known as the paradoxical frog or shrinking frog, is a species of hylid frog from South America. Its name refers to the very large—up to long—

tadpole A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found ...

(the world's longest), which in turn "shrinks" during metamorphosis into an ordinary-sized frog, only about a quarter or third of its former length. Although the recordholder was a tadpole in Amapá that belonged to this species, others in the genus ''

Pseudis ''Pseudis'' is a genus of South American frogs (swimming frogs) in the family Hylidae. They are often common and frequently heard, but easily overlooked because of their camouflage and lifestyle, living in lakes, ponds, marshes and similar waters ...

'' also have large tadpoles and ordinary-sized adults.

Distribution and habitat

The species inhabits ponds, lakes, lagoons and similar waters from the

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technolog ...

and

the Guianas The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories: * French Guiana, an overseas department and region of France * ...

, to

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

and

Trinidad Trinidad is the larger and more populous of the two major islands of Trinidad and Tobago. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is often referred to as the southernmos ...

, with a disjunct distribution in the Magdalena River watershed in Colombia and adjacent far western Venezuela. More southerly populations from the

Pantanal The Pantanal () is a natural region encompassing the world's largest tropical wetland area, and the world's largest flooded grasslands. It is located mostly within the Brazilian state of Mato Grosso do Sul, but it extends into Mato Grosso and ...

region to northeastern

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

have been recognized as a subspecies, but are now often considered a full species, '' P. platensis'', although the validity of this split is questionable.

Appearance and behavior

The adult frogs of ''P. paradoxa'' have a snout–to–

vent Vent or vents may refer to: Science and technology Biology *Vent, the cloaca region of an animal * Vent DNA polymerase, a thermostable DNA polymerase Geology *Hydrothermal vent, a fissure in a planet's surface from which geothermally heated wate ...

length of and are green to brown coloured with dark green, olive or dark brownish stripes or mottling; the pattern and hue varies significantly. The female of ''P. paradoxa'' lay eggs among water plants; the eggs develop into tadpoles. They always reach a large size, but there are noticeable local variations in the final size of the tadpoles, with those in large temporary waters with plenty of food and few aquatic predators growing larger than those in smaller waters with less food or waters with more aquatic predators. The tadpoles feed mostly on algae. The adult frogs, which are active both day and night and always in or near water, eat insects (such as flies, beetles, true bugs, plantsuckers, butterflies, moths and dragonflies)Franklyn, D. (2015). . The Online Guide to the Animals of Trinidad and Tobago. Retrieved 7 January 2020 and other invertebrates (such as crabs),Franklyn, D. (2015). . The Online Guide to the Animals of Trinidad and Tobago. Retrieved 7 January 2020 and small frogs.Franklyn, D. (2015). . The Online Guide to the Animals of Trinidad and Tobago. Retrieved 7 January 2020 When threatened, the frog uses its strong toes with an extra joint to stir up the muddy bottom and hide. The frog also uses this mechanism to find food on the bottom of lakes and ponds.

Potential use in medicine

In March 2008, scientists working from the Universities of

Ulster Ulster (; ga, Ulaidh or ''Cúige Uladh'' ; sco, label= Ulster Scots, Ulstèr or ''Ulster'') is one of the four traditional Irish provinces. It is made up of nine counties: six of these constitute Northern Ireland (a part of the United Kin ...

and

United Arab Emirates The United Arab Emirates (UAE; ar, اَلْإِمَارَات الْعَرَبِيَة الْمُتَحِدَة ), or simply the Emirates ( ar, الِْإمَارَات ), is a country in Western Asia ( The Middle East). It is located at t ...

released findings of a study on pseudin-2, a skin compound which protects the paradoxical frog from infection. This work found that a synthetic version of this compound was able to stimulate the secretion of insulin in pancreatic cells under laboratory conditions without

toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

to the cells. As such, this synthetic medicine could be used in the treatment of

Type 2 diabetes Type 2 diabetes, formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urinatio ...

References

External links

* * {{DEFAULTSORT:Pseudis Paradoxa Amphibians of Bolivia Amphibians of Brazil Amphibians of Colombia Amphibians of French Guiana Amphibians of Guyana Amphibians of Peru Amphibians of Suriname Amphibians of Trinidad and Tobago Amphibians of Venezuela Amphibians described in 1758 Taxa named by Carl Linnaeus paradoxa