Poison dart frog

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Poison dart frogs

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Suborder: Neobatrachia
Superfamily: Dendrobatoidea
Family: Dendrobatidae
Cope, 1865

Distribution of Dendrobatidae (in black)
Subfamilies and genera

Poison dart frog (also dart-poison frog, poison frog or formerly poison arrow frog) is the common name of a group of frogs in the family Dendrobatidae which are native to Central and South America. Unlike most frogs, species are active during the day, and often exhibit brightly-colored bodies. Although all dendrobatids are at least somewhat toxic in the wild, levels of toxicity vary considerably from one species to the next, and from one population to another. Many species are critically endangered. These amphibians are often called "dart frogs" due to indigenous Amerindians' use of their toxic secretions to poison the tips of blowdarts.[1] In fact, of over 175 species, only three have been documented as being used for this purpose (curare plants are more commonly used), and none come from the Dendrobates genus, which is most characterized by the brilliant color and complex patterns of its members.[2][3]

Contents

[edit] Characteristics

Dyeing dart frog (Dendrobates tinctorius).

Most species of poison dart frogs are small, sometimes less than 1.5 centimetres (0.59 in) in adult length, although a few are up to 6 centimetres (2.4 in) in length. They weigh about 2 grams, depending on the size of the frog. Most poison dart frogs are brightly colored, displaying aposematic patterns to warn potential predators. Unlike most other frogs, they are diurnal, rather than being primarily nocturnal or crepuscular.[4]

They lay their eggs in moist places, including on leaves, in plants, among exposed roots, and elsewhere, and allow the tadpoles to wriggle onto their backs shortly after they hatch. They then carry the piggy-backed tadpoles to water, where the larva remain until metamorphosis. The water is typically a pool, but some species use the water gathered in bromeliads or other plants; and some species provide food, supplying the tadpoles with unfertilized eggs to eat.[4]

[edit] Habitat

Poison dart frogs are endemic to humid, tropical environments of Central and Latin America (South America).[2] These frogs are generally found in tropical rainforests, including in Bolivia, Puerto Rico, Costa Rica, Brazil, Colombia, Ecuador, Venezuela, Suriname, French Guyana, Peru, Panama, Nicaragua and non-native to Hawaii.[2][5] Dendrobatids tend to live on or close to the ground, as well as in trees as much as 10 metres (33 ft) from the ground.[6]

[edit] Reproduction

Many species of poison dart frog are dedicated parents. The red-and-blue poison-arrow frog (Dendrobates pumilio) carry their newly hatched tadpoles into the canopy. The tadpoles stick to the mucus on the back of their parents. Once in the upper reaches of the rainforest tress the parents deposit their young in the pools of water that accumulate in epiphytic plants such as bromeliads. The tadpoles feed on invertebrates in their arboreal nursery and their mother will even supplement their diet by depositing eggs into the water.[7]

[edit] Taxonomy

Dart frogs are the focus of major phylogenetic studies, and undergo taxonomic changes frequently.[8] Family Dendrobatidae was revised taxonomically in 2006 and contains 11 to 12 genera, with over 200 species.[2][9][10][11]

[edit] Color morphs

Some poison dart frogs species include a number of conspecific color morphs that have emerged as early as 6,000 years ago.[12] Therefore, species such as Dendrobates tinctorius can include color pattern morphs that can be interbred (colors are under polygenic control, while the actual patterns are probably controlled by a single locus).[13] Differing coloration has historically misidentified single species as separate, and there is still controversy among taxonomists over classification.[14]

[edit] Toxicity and medicine

See also: Allopumiliotoxin 267A, Batrachotoxin, Epibatidine, Histrionicotoxin, and Pumiliotoxin 251D
The skin of the phantasmal poison frog contains epibatidine.

Many poison dart frogs secrete lipophilic alkaloid toxins through their skin. As a result, they are able to be active alongside potential predators during the day.[2][15] Dart frogs also do not synthesize their poisons, but sequester the chemicals from prey items, such as ants and mites. Because of this, captive-bred animals do not contain significant levels of toxins. Despite the toxins utilized by some poison dart frogs, there are some predators that have developed the ability to withstand them, including the Amazon ground snake (Liophis epinephelus).[16]

Chemicals extracted from the skin of Epipedobates tricolor may be shown to have medicinal value.[17] One such chemical is a painkiller 200 times as potent as morphine, called epibatidine, that has unfortunately demonstrated unacceptable gastrointestinal side effects in humans.[18] Secretions from dendrobatids are also showing promise as muscle relaxants, heart stimulants and appetite suppressants.[19]

[edit] Captive care

See also: History of dendrobatid frogkeeping

All species of poison dart frogs are neotropical in origin. Wild-caught specimens can maintain toxicity for some time, so appropriate care should be taken when handling such animals.[20] While there is scant scientific study on the lifespan of poison dart frogs, retagging frequencies indicate it can range from one to three years in the wild.[21] In captivity, most species thrive where the humidity is kept constant at 80 to 100% and where the temperature is around 72 °F (22 °C) to 80 °F (27 °C) during the day and no lower than 60 °F (16 °C) to 65 °F (18 °C) at night. Some species tolerate lower temperatures better than others.

[edit] Conservation status

Further information: Decline in amphibian populations

Like many frog families, dendrobatids have also been affected by the worldwide decline in amphibian populations. Habitat loss (due to logging and farming) and predation by introduced species are the more common causes, but mostly the cutaneous chytridiomycosis has struck the dart frogs the hardest in the past 25 years.[22] Zoos have tried to counteract this disease by treating captive frogs with an antifungal agent that is used to kill athlete's foot in humans.[23]

[edit] See also

[edit] References

  1. ^ Myers, C. W., J. W. Daly, and B. Malkin (1978). "A dangerously toxic new frog (Phyllobates) used by Embera Indians of western Colombia, with discussion of blowgun fabrication and dart poisoning". Bull. Amer. Mus. Nat. Hist. 161 (2): 307–366. 
  2. ^ a b c d e "AmphibiaWeb - Dendrobatidae". AmphibiaWeb. http://amphibiaweb.org/lists/Dendrobatidae.shtml. Retrieved on 2008-10-10. 
  3. ^ Heying, H. (2003). "Dendrobatidae". Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Dendrobatidae.html. Retrieved on 2008-09-18. 
  4. ^ a b Zweifel, Robert G. (1998). Cogger, H.G. & Zweifel, R.G.. ed. Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press. pp. 95–97. ISBN 0-12-178560-2. 
  5. ^ "Poison Dart Frogs in Hawaii". Explore Biodiversity. http://www.explorebiodiversity.com/Hawaii/BiodiversityForgotten/Wildlife/Reptiles/Frogs%20-%20Poison.htm. Retrieved on 2008-10-21. 
  6. ^ Kristiina Hurme, Kittzie Gonzalez, Mark Halvorsen, Bruce Foster, and Don Moore (2003). "Environmental Enrichment for Dendrobatid Frogs". Journal of Applied Animal Welfare Science (Lawrence Erlbaum Associates, Inc.) 6 (4): 285–299. doi:10.1207/s15327604jaws0604_3. 
  7. ^ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.
  8. ^ Grant, T., Frost, D. R., Caldwell, J. P., Gagliardo, R., Haddad, C. F. B., Kok, P. J. R., Means, D. B., Noonan, B. P., Schargel, W. E., and Wheeler, W. C. (2006). "Phylogenetic systematics of dart-poison frogs and their relatives (Amphibia: Athesphatanura: Dendrobatidae)". Bulletin of the American Museum of Natural History (American Museum of Natural History) 299 (299): 1–262. doi:10.1206/0003-0090(2006)299[1:PSODFA]2.0.CO;2. http://digitallibrary.amnh.org/dspace/bitstream/2246/5803/1/B299.pdf. 
  9. ^ "Amphibian Species of the World". The American Museum of Natural History. http://research.amnh.org/herpetology/amphibia/names.php?taxon=&family=Dendrobatidae&subfamily=&genus=&commname=&authority=&year=&geo=0&dist=&comment=. Retrieved on 2008-10-10. 
  10. ^ "All Genera". Dendrobatenwelte.de. http://www.dendrobatenwelt.de/bneuneu.htm. Retrieved on 2008-10-11. 
  11. ^ F. Harvey Pough ... (2004). Herpetology. Upper Saddle River, NJ: Pearson/Prentice Hall. pp. 92. ISBN 0131008498. 
  12. ^ Summers, K; Symula, R; Clough, M; Cronin, T (Nov 1999). "Visual mate choice in poison frogs.". Proceedings. Biological sciences / the Royal Society 266 (1434): 2141–5. doi:10.1098/rspb.1999.0900. PMID 10649631. 
  13. ^ Summers K., Cronin T. W., Kennedy T. (2004). "Cross-breeding of distinct color morphs of the Strawberry Poison Frog (Dendrobates pumilio) from the Bocas del Toro Archipelago, Panama". Journal of Herpetology 38 (1): 1–8. doi:10.1670/51-03A. http://cat.inist.fr/?aModele=afficheN&cpsidt=15605003. 
  14. ^ PJR Kok, RD MacCulloch, P Gaucher, EH Poelman, GR Bourne, A Lathrop, GL Lenglet (2006). "A new species of Colostethus (Anura, Dendrobatidae) from French Guiana with a redescription of Colostethus beebei (Noble, 1923) from its type locality". Phyllomedusa 5 (1): 43–66. http://www.phyllomedusa.esalq.usp.br/articles/volume5/number1/514366.pdf. 
  15. ^ Cannatella, David (1995). "Dendrobatidae. Poison-arrow frogs, Dart-poison frogs, Poison-dart frogs". The Tree of Life Project. http://tolweb.org/Dendrobatidae/16956/1995.01.01. Retrieved on 2008-10-23. 
  16. ^ C.W. Myers, J.W. Daly, and B. Malkin (1978). "A dangerously toxic new frog (Phyllobates) used by the Emberá Indians of western Colombia, with discussion of blowgun fabrication and dart poisoning.". Bulletin of the American Museum of natural history 161 (2): pp. 307–365 + color pls. 1–2. 
  17. ^ "Science: Potent painkiller from poisonous frog - 30 May 1992 - New Scientist". New Scientist. http://www.newscientist.com/article/mg13418232.900-science-potent-painkiller-from-poisonous-frog-.html. Retrieved on 2008-10-10. 
  18. ^ Prince and Sine (2008). "Epibatidine Activates Muscle Acetylcholine Receptors with Unique Site Selectivity". Biophysical Journal (Biophysical Journal) 75 (4): 1817. doi:10.1016/j.soildyn.2007.11.006. PMID 9746523. http://www.biophysj.org/cgi/content/full/75/4/1817. Retrieved on 2008-10-10. 
  19. ^ "San Diego Zoo's Animal Bytes: Poison Frog". Zoological Society of San Diego. http://www.sandiegozoo.org/animalbytes/t-poison_frog.html. Retrieved on 2008-10-10. 
  20. ^ Stefan, Lötters; Jungfer, Henkel, Schmidt (2007). Poison Frogs: Biology, Species, & Captive Husbandry. Serpent's Tale. pp. 110–136. ISBN 3930612623. 
  21. ^ Gray, HM, et al. (2002). "Traumatic Injuries in Two Neotropical Frogs Dendrobates auratus and Physalaemus pustulosus". Journal of Herpetology 36 (1): 117–121. doi:10.1051/forest:19940309. 
  22. ^ Daszak P, Berger L, Cunningham AA, Hyatt AD, Green DE, Speare R. (1999). "Emerging infectious diseases and amphibian population declines". Emerg. Infect. Dis. (5): 735–48. 
  23. ^ "Poison Dart Frog Fact Sheet - National Zoo| FONZ". Smithsonian National Zoological Park. http://nationalzoo.si.edu/Animals/Amazonia/Facts/fact-poisondartfrog.cfm. Retrieved on 2008-10-10. 

[edit] External links

Search Wikispecies Wikispecies has information related to: Dendrobatidae

[edit] Media

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Extant anuran families by suborder
Kingdom Animalia · Phylum Chordata · Subphylum Craniata · Superclass Tetrapoda · Class Amphibia
Archaeobatrachia White-lipped Tree Frog
Mesobatrachia
Neobatrachia
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Toxins (enterotoxin/neurotoxin/hemotoxin/cardiotoxin)
Bacterial toxins
Mycotoxins
Invertebrates
Vertebrates
note: some toxins are produced by lower species and pass through intermediate species
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