Splendid Poison Frog

Wanted: Oophaga speciosa

The not particularly shy, diurnal, strikingly red splendid poison frog was hard to miss, especially since its range in western Panama was quite small. This is probably exactly what proved fatal for the amphibian from the family of poison frogs (Dendrobatidae): The splendid poison frog was extremely popular in the international exotic pet and pet trade. After some animals (probably the last ones) were captured in 1992 and exported from Panama to the United States, no specimen could be found again. Although the IUCN has listed the splendid poison frog as extinct on its Red List since 2020, it points out that there is a minimal chance that some terrarium or frog enthusiast out there still keeps the once very common splendid poison frog at home in a terrarium.

Splendid poison frogs lived only in a very small area of the Cordillera Central mountain range in western Panama, near the border with Costa Rica. The frog species occurred along a watershed in the upper valley of the Chiriquí River at an elevation of 1,100 to 1,400 meters above sea level. Splendid poison frogs were ground dwellers and preferred humid lowland and submontane montane rainforests and cloud forests with humidity of 80 to 100 percent. At night, the frogs stayed at their resting places, usually on leaves and flowers.

Splendid poison frog – fact sheet

alternative names	Splendid poison-arrow frog, Panamanian red poison dart frog
scientific names	Oophaga speciosa, Dendrobates speciosus, Oophaga speciosus, Hylaplesia speciosa
original distribution area	Panama
time of extinction	1992
causes of extinction	Fungal disease, exotic pet trade, habitat loss
IUCN status	extinct

Splendid poison frog: It was not used as arrow poison, but it was still poisonous

Poison frogs are often also called poison dart frogs or dyeing frogs. The term poison dart frogs as another name for the frogs and toads (Anura) that belong to the poison frog family is misleading. The skin secretion of by no means all species is used as arrow poison. Strictly speaking, only three species from the genus of poison-dart frogs (Phyllobates) are used by Indigenous peoples in western Colombia as arrow poison when hunting with a blowgun. Poison-dart frogs release a highly potent neurotoxin called batrachotoxin through their skin.

All poison frogs secrete basic alkaloids through their skin, of which scientists have so far been able to identify more than 230 variants. The frogs are not able to synthesize toxins themselves. They can only form toxins by eating poisonous prey animals, such as certain mites, beetles or ants. The toxins are sequestered in their bodies, so that the poisons are stored in or under their skin. Poison frogs kept in human care lose their toxicity over time, because they usually lack the poisonous food animals there.

M. W. Edwards and his colleagues analyzed the skin secretion of the splendid poison frog in 1988. The researchers were able to detect at least 30 different alkaloids, including various pumiliotoxins and allopumiliotoxins. The frogs absorb these highly toxic substances by eating some oribatid mites (Oribatida) and formicine ants (Formicinae).

Wiped out by chytridiomycosis?

The splendid poison frog, once considered common, was last seen in 1992. Several targeted searches between 2008 and 2012 proved unsuccessful. Most scientists assume that the chytrid fungus (Batrachochytrium dendrobatidis), which reached the former range of the splendid poison frog in 1996, ultimately brought about the species’ final decline. The fungus infects the skin of amphibians and causes a disease called chytridiomycosis.

Chytridiomycosis can be fatal, especially for amphibians living in cooler regions of the Andes. For this reason, the poison frog or Dendrobates species in particular were especially susceptible to the fungal disease, which probably originally came from Africa. That is why the fungus is also named B. dendrobatidis.

Scientists consider certain factors that weaken the amphibians’ immune system to favor infection with chytrid fungi. These include primary diseases (such as worms), stress caused by climatic changes, rapid shifts from the dry to the rainy season, or malnutrition.

According to an Australian study from 2019, fungal diseases such as chytridiomycosis have caused enormous population collapses in more than 500 amphibian species over the past 50 years. Ninety species are now considered extinct, including the splendid poison frog, McCranie’s robber frog, the Corquin robber frog, the Chiriqui harlequin frog and Rabb’s fringe-limbed treefrog.

Wild-caught colorful, small poison frogs for the zoo trade in North America and Europe still threaten the populations of some poison frog genera today. The deforestation of the rainforest also continues to pose an enormous threat—today as in the past.

Breeding splendid poison frogs in human care was considered a challenge

All nine species of the genus Oophaga, which also includes the splendid poison frog, are or were kept as pets in terrariums, but the reproduction of the amphibians is considered challenging. One exception seems to be the strawberry poison frog (Oophaga pumilio), which is easier to breed in captivity.

The breeding biology of poison frogs is partly complex. This was also true of the splendid poison frog: Its tadpoles feed exclusively on the unfertilized nutritive eggs produced by female frogs, which have a special composition. In breeding programs, egg yolk or a curd mixture is often fed to the larvae as a substitute, and they accept it. However, the development of the tadpoles takes much longer this way, namely 162 days instead of around 80 days under natural rearing conditions, writes frog researcher Karl-Heinz Jungfer in his Contribution to the Knowledge of Dendrobates speciosus (1985). In addition, artificially reared tadpoles later developed matchstick legs.

The female splendid poison frog carries the larvae individually on her back after they hatch and takes them to different bromeliad leaf axils, where she deposits them. The bromeliad tanks contain so-called phytotelmata: tiny bodies of water that usually form from rain in a depression in terrestrial plants. At irregular intervals, the female visits the small water bodies in the bromeliads with her larvae to lay four to ten nutritive eggs there. The tadpoles bite through the jelly and eat the eggs. Under natural conditions, the complete metamorphosis of the larvae took 78 to 84 days.

The artificial rearing of splendid poison frogs, for example with egg yolk, proved laborious and often resulted in developmental disorders. The breeder also had to keep in mind that the tadpoles must be kept separate from one another, otherwise they will eat each other. Almost only with natural brood care could fully developed and resilient poison frogs be bred.

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