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 25 cm (10 in) long—tadpole (typical of the genus Pseudis), which in turn becomes an ordinary-sized frog, only about a quarter of its former length.
Pseudis paradoxa is green coloured with dark green or olive stripes. It inhabits ponds, lakes and lagoons from northern Argentina, through the Pantanal, Amazon and the Guianas, to Venezuela and Trinidad, with a disjunct distribution in the Magdalena River watershed in Colombia and adjacent far western Venezuela. The female frog lays eggs among water plants; the eggs develop into giant tadpoles.
These amphibians feed on larvae, small insects, and tiny invertebrates. The frog is a nocturnal animal and spends most of its life in water. 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.
In March 2008, scientists working from the Universities of Ulster and United Arab Emirates 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 to the cells. As such, this synthetic medicine could be used in the treatment of Type 2 diabetes.
- Angulo, Ariadne; Baldo, Diego (2010). "Pseudis paradoxa". The IUCN Red List of Threatened Species. IUCN. 2010: e.T55904A11385563. doi:10.2305/IUCN.UK.2010-2.RLTS.T55904A11385563.en. Retrieved 26 December 2017.
- Frost, Darrel R. (2013). "Pseudis paradoxa (Linnaeus, 1758)". Amphibian Species of the World 5.6, an Online Reference. American Museum of Natural History. Retrieved 24 October 2013.
- Emerson, S. B. (1988). "The giant tadpole of Pseudis paradoxa". Biological Journal of the Linnean Society. 34 (2): 93–104. doi:10.1111/j.1095-8312.1988.tb01951.x.
- Abdel-Wahab, Y.H.A.; Power, G.J.; Ng, M.T.; Flatt, P.R.; Conlon, J.M. (2008). "Insulin-releasing properties of the frog skin peptide pseudin-2 and its [Lys18]-substituted analogue". Biological Chemistry. 389 (2): 143–148. doi:10.1515/BC.2008.018. PMID 18163889.
- "Health | Frog skin diabetes treatment hope". BBC News. 3 March 2008. Retrieved 9 October 2013.