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Golden poison frog
Conservation status
Endangered  (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Amphibia
Order:	Anura
Family:	Dendrobatidae
Genus:	Phyllobates
Species:	P. terribilis
Binomial name
Phyllobates terribilis Myers [fr], Daly, and Malkin, 1978

The golden poison frog (Phyllobates terribilis), also known as the golden dart frog or golden poison arrow frog, is a poison dart frog endemic from the rainforests of Colombia. The golden poison frog has become endangered due to habitat destruction within its naturally limited range. Despite its small size, this frog is considered to be the most poisonous extant animal species on the planet.

Taxonomy and etymology

The golden poison frog was described as Phyllobates terribilis in 1978 by herpetologists Charles W. Myers and Borys Malkin as well as biochemist John W. Daly; the species name terribilis is a reference to the deadly toxins present in the skin secretions of this species. Myers' research was based on hundreds of specimens collected on an expedition to the Quebrada Guangui and La Brea regions of the Colombian rainforest, and a breeding colony of 18 frogs established at the American Museum of Natural History.

Distribution and habitat

The golden poison frog is endemic to humid forests of the Pacific coast of Colombia in the Cauca and Valle del Cauca Departments in the Chocó Rainforest. The optimal habitat of this species is the rainforest with high rain rates (5 m or more per year), altitudes from sea level to 200 m elevation, temperatures of at least 26 °C, and relative humidity of 80–90%. It is known only from primary forest. The eggs are laid on the ground; the males transport the tadpoles to permanent pools. Its range is less than 5,000 square km; destruction of this habitat has contributed to P. terribilis becoming an endangered species.

Description

The golden poison frog is the largest species of the poison dart frog family, and can reach a weight of nearly 30 grams with a length of 6 cm as adults. Females are typically larger than males. The adults are brightly colored, while juvenile frogs have mostly black bodies with two golden-yellow stripes along their backs. The black fades as they mature, and at around 18 weeks of age the frog is fully colored. The frog's color pattern is aposematic (a coloration to warn predators of its toxicity). Despite their common name, golden poison frogs occur in four main color varieties or morphs:

Yellow

The yellow morph is the reason Phyllobates terribilis has the common name golden poison frog. These frogs can be pale yellow to deep, golden yellow in color. Yellow Phyllobates terribilis specimens are found in Quebrada Guangui, Colombia.

Mint green

The largest morph of Phyllobates terribilis exists in the La Brea and La Sirpa areas in Colombia; despite the name "mint green" these frogs can be metallic green, pale green, or white.

Orange

Orange examples of Phyllobates terribilis exist in Colombia, as well. They tend to be a metallic orange or yellow-orange in color, with varying intensity. They have been observed living near yellow specimens in Quebrada Guangui, Colombia, and it is unclear to what extent these represent an individual subpopulation or locality distinct from the yellow morph.

Orange blackfoot

The orange blackfoot morph is a captive bred line established by Tesoros de Colombia, a Colombian company that aims to reduce poaching of wild dart frogs by breeding rare species and flooding the pet trade with low cost animals to decrease the value of wild specimens to poachers. This morph is golden yellow to a deep orange. They have dark markings on their feet, throat, vent, and rump that range from distinct black to nearly absent or speckled grey.

• Phyllobates terribilis color morphs
• Yellow
• Mint green
• Orange
• Orange blackfoot

Ecology and behavior

The frog is normally diurnal; golden poison frogs live evenly spaced without forming larger congregations.

Diet

This species is an unspecialized ambush hunter; an adult frog can eat food items much larger in relation to its size than most other dendrobatids. The main natural sources of food of P. terribilis are the ants in the genera Brachymyrmex and Paratrechina, but many kinds of insects and other small invertebrates can be eaten, specifically termites and beetles, which can easily be found on the rainforest floor. Tadpoles feed on algae, mosquito larvae, and other edible material that may be present in their environment.

Breeding

Males advertise to receptive females with a trilling call. Golden poison frogs are notable for demonstrating tactile courtship during reproduction, each partner stroking its mate's head, back, flanks, and cloacal areas prior to egg deposition. The eggs are fertilized externally. The golden poison frogs lay their eggs on the ground, hidden beneath leaf litter. Once the tadpoles emerge from their eggs, they stick themselves to the mucus on the backs of their parents. The adult frogs carry their young into the canopy, depositing them in the pools of water that accumulate in the centre of bromeliads and water-filled tree holes. The tadpoles feed on algae and mosquito larvae in their nursery.

Predators

Golden poison frogs are so toxic that adult frogs likely have few – if any – predators. The snake species Leimadophis epinephelus has shown resistance to several frog toxins including batrachotoxin, and has been observed to eat juvenile frogs without ill effects.

Toxicity

The golden poison frog is one of the most poisonous animals on the planet; these frogs produce deadly alkaloid batrachotoxins in their skin glands as a defense against predators. To become poisoned a predator generally must attempt to consume the frog, although this species is so toxic that even touching an individual frog can be dangerous. This extraordinarily lethal poison is very rare. Batrachotoxin is found only in three poisonous frogs from Colombia (all genus Phyllobates), a few birds from Papua New Guinea, and four Papuan beetles of the genus Choresine in the family Melyridae. Batrachotoxin affects the sodium channels of nerve cells. While it is unknown how the frog avoids poisoning itself, other species of poisonous frogs have been demonstrated to express a "toxin sponge" protein in blood plasma, internal organs, and muscle that binds and sequesters the toxin so as to prevent autointoxication.

Mechanism

Batrachotoxin binds to, and irreversibly opens, the sodium channels of nerve cells leaving the muscles in an inactive state of contraction, which can lead to paralysis, heart fibrillation, heart failure, and death. The average dose carried will vary between locations, and consequent local diet, but the average wild golden poison frog is generally estimated to contain about one milligram of poison, enough to kill between 10 and 20 humans, or up to two African bull elephants. Smaller doses have been shown to cause seizures, salivation, muscle contractions, dyspnoea and death in mice: the subcutaneous LD50 is just 0.2 μg/kg, although low doses such as 0.01 μg/kg and 0.02 μg/kg may be lethal. Myers et al. estimate that the lethal dose for humans is between 2.0 and 7.5 μg.

Synthesis

Golden poison frogs appear to rely on the consumption of small insects or other arthropods to synthesize batrachotoxin; frogs kept in captivity fed on commercially available feeder insects will eventually lose their toxicity, and frogs bred in captivity are considered non-toxic. It is not clear which prey species supplies the potent alkaloid that gives golden poison frogs their exceptionally high levels of toxicity, or whether the frogs modify another available toxin to produce a more efficient variant, as do some of the frogs from the genus Dendrobates. Scientists have suggested the crucial prey item may be a small beetle from the family Melyridae. At least one species of these beetles produces the same toxin found in golden poison frogs. Their relatives in Colombian rainforests could be the source of the batrachotoxins found in the highly toxic Phyllobates frogs of that region.

Use by indigenous people

Golden poison frogs are a very important frog to the local indigenous cultures, such as the Emberá and Cofán people in Colombia's rainforest. The frog is the main source of the poison in the darts used by the natives to hunt their food. The Emberá people carefully expose the frog to the heat of a fire, and the frog exudes small amounts of poisonous fluid. The tips of arrows and darts are soaked in the fluid, and remain deadly for two years or longer.

In captivity

The golden poison frog is a popular vivarium subject due to its bright color and bold personality in captivity. Despite its dangerous toxicity in the wild, captive specimens raised without their natural food sources are non-toxic in captivity. Due to their small range in the wild, poaching for the pet trade formerly represented a serious threat to the survival of the species. Due to efforts of frog breeders like Tesoros de Colombia, captive bred frogs are now widely available for the pet trade. As these specimens are legal, non-toxic, healthier, and less expensive when compared to poached animals, the demand for illegally obtained wild caught specimens has decreased. Today, the IUCN estimates that the majority of golden poison frogs sold for the pet trade are legally produced from captive lines, and estimates the threat from collection for the pet trade to be small.

References

1. ^ IUCN SSC Amphibian Specialist Group (2017). "Phyllobates terribilis". IUCN Red List of Threatened Species. 2017: e.T55264A85887889. doi:10.2305/IUCN.UK.2017-3.RLTS.T55264A85887889.en. Retrieved 12 November 2021.
2. ^ Myers, C.W.; Daly, J.W. & B. Malkin (1978). "A dangerously toxic new frog (Phyllobates) used by Embera Indians of western Colombia with discussion of blowgun fabrication and dart poisoning". Bulletin of the American Museum of Natural History. 161: 307–366. hdl:2246/1286.
3. ^ Frost, Darrel R. (2022). "Phyllobates terribilis Myers, Daly, and Malkin, 1978". Amphibian Species of the World: An Online Reference. Version 6.1. American Museum of Natural History. doi:10.5531/db.vz.0001. Retrieved 8 March 2022.
4. ^ "Phyllobates terribilis". AmphibiaWeb. University of California, Berkeley. Retrieved 8 March 2022.
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7. "Largest poison-dart frog species". Guinness World Records. 13 January 2014. Retrieved 2 March 2022.
8. Summers, Kyle; Clough, Mark E. (22 May 2001). "The evolution of coloration and toxicity in the poison frog family (Dendrobatidae)". Proceedings of the National Academy of Sciences. 98 (11): 6227–6232. Bibcode:2001PNAS...98.6227S. doi:10.1073/pnas.101134898. ISSN 0027-8424. PMC 33450. PMID 11353830.
9. ^ Lötters, Stefan (2007). Poison frogs: biology, species & captive care. Frank Mutschmann. Frankfurt am Main. pp. 431–433. ISBN 978-3-930612-62-8. OCLC 174929258.{{cite book}}: CS1 maint: location missing publisher (link)
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11. ^ Clare, John (16 May 2012). "Care Tips For The Golden Dart Frog - Reptiles Magazine". Retrieved 27 February 2022.
12. ^ Márquez, Roberto; et al. (2012). "Range extension of the critically endangered true poison-dart frog, Phyllobates terribilis (Anura: Dendrobatidae), in western Colombia". Acta Herpetologica. 7 (2): 341–345. CiteSeerX 10.1.1.845.8708.
13. ^ "Atlas Dr. Pez : Phyllobates terribilis". Archived from the original on 13 December 2007. Retrieved 11 September 2007.
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15. "Poison Frog | San Diego Zoo Animals & Plants". animals.sandiegozoo.org. Retrieved 25 January 2022.
16. ^ "Golden Poison Frog". American Museum of Natural History. Retrieved 24 January 2022.
17. ^ "Dart poison frogs and their toxins". ResearchGate.
18. Maksim V. Plikus; Maksim V.; Astrowski, Alaiksandr A. (2014). "Deadly hairs, lethal feathers – convergent evolution of poisonous integument in mammals and birds". Experimental Dermatology. 23 (7): 466–468. doi:10.1111/exd.12408. PMID 24698054. S2CID 205127015.
19. ^ Dumbacher, John P.; Wako, Avit; Derrickson, Scott R.; Samuelson, Allan; Spande, Thomas F.; Daly, John W. (2004). "Melyrid beetles (Choresine): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds". Proceedings of the National Academy of Sciences. 101 (45): 15857–15860. Bibcode:2004PNAS..10115857D. doi:10.1073/pnas.0407197101. PMC 528779. PMID 15520388.
20. Abderemane-Ali, Fayal; Rossen, Nathan D.; Kobiela, Megan E.; Craig, Robert A.; Garrison, Catherine E.; Chen, Zhou; Colleran, Claire M.; O’Connell, Lauren A.; Du Bois, J.; Dumbacher, John P.; Minor, Daniel L. (6 September 2021). "Evidence that toxin resistance in poison birds and frogs is not rooted in sodium channel mutations and may rely on "toxin sponge" proteins". Journal of General Physiology. 153 (9): e202112872. doi:10.1085/jgp.202112872. ISSN 0022-1295. PMC 8348241. PMID 34351379.
21. Alvarez, Mariela C.; Wiley, Mary. "Phyllobates terribilis". Animal Diversity Web.
22. ^ "USATODAY.com - Most poisonous creature could be a mystery insect". usatoday30.usatoday.com. Retrieved 8 July 2016.
23. "WonderQuest: Most poisonous animal, Contentious ethanol debate, Do fish sleep?". 30 October 2013. Archived from the original on 30 October 2013.

External links

• The True Poison-Dart Frog: The Golden Poison Frog Phyllobates terribilis
• The most poisonous animal (retrieved Oct 30, 2013)
• Golden Poison Dart Frog at National Geographic

• Frogs

• IUCN Red List endangered species
• Phyllobates
• Amphibians of Colombia
• Endemic fauna of Colombia
• Amphibians described in 1978
• Taxa named by Charles W. Myers