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Those colorful harlequin frogs

Male and female Atelopus zeteki in amplexus. Introduced into a vivarium with a female to trigger reproduction, a male A. zeteki climbed onto the back of his partner (amplexus) in less than six hours. Amplexus allows a male to be well-positioned for fertilizing a female’s eggs when they are laid. While amplexus often lasts between 30 to 60 days for this species, in this case, it lasted 37 days, during which time the male did not eat.
Credit: Biodôme de Montréal (Roxan Ouimet)
Male and female Atelopus zeteki in amplexus.
  • Male and female Atelopus zeteki in amplexus.
  • The first clutch of eggs.
  • Appearance of the tadpoles at 49 days post-lay.
  • A young metamorphosed Atelopus zeteki.
Those colorful harlequin frogs

The term harlequin refers to a character in traditional Italian comedy-type theater who was typically dressed in a colorful and often diamond-patterned costume. As such, harlequin frogs, which form a group of a hundred or so species belonging to the genus Atelopus, wear their name well. They too are brightly colored, which can serve to warn predators that they are toxic, and they frequently also don a pattern that could render a zebra jealous! More toad (Family Bufonidae) than frog, the audacious appearance of these amphibians most certainly helped them to carve out a place in the heart of humans. Notably, Arhuaco native Colombians have depended on the “starry night” harlequin frog for ages, to determine when to sow their land or organize spiritual ceremonies. Ancient Panamanian narratives affirm that the Panamanian Golden frog (A. zeteki) transforms into gold when it dies. Today, the Panamanian Golden frog is not only portrayed as a symbol of good luck on state lottery tickets, but one day per year, on the 14th of August, or el Día de la Rana Dorada, it is venerated by the Panamanian people.

Harlequin frogs were at the heart of much research during the 1980s. For this reason, it became rapidly obvious when many of their populations suddenly began to decline, or even disappear, without explanation! After sharing similar observations concerning other amphibian species around the world, amphibian researchers established an international collaborative effort to determine the root cause of these worrisome events.This is how we became aware that a deadly pandemic caused by a pathogenic fungus called Batrachochytrium dendrobatidis, or the chytrid fungus, described in a previous blog, was globally wreaking havoc. Today, we believe that Harlequin frogs have been especially hard-hit by the chytrid fungus for two reasons. Firstly, they display a high rate of endemism, meaning that many species of these frogs live within a very restrained area, and secondly, they have a tendency to live in tropical montane forests, situated at higher elevations, where the cool and moist conditions are favourable to the growth of the chytrid fungus. Depending on the source of the information that one may read, only ten or so species of Harlequin frogs are thought to remain unaffected by any major threat. Unfortunately, somewhere between 30 and 40 species of these frogs are presumed to be extinct, while the rest are in decline, primarily due to the chytrid fungus.

The Panamanian Golden frog, extinct in its natural habitat

At the end of the 1980’s, researchers were striving to protect one particular harlequin frog, known as the Panamanian Golden frog, from overharvesting in nature, for the purposes of resale or exposure in vivariums by local hotels and zoos, when they became aware of the imminent invasion of the chytrid fungus. This group of researchers desperately established a care facility onsite and collected as many individual frogs as possible in the hopes of saving them from almost certain extinction. Some zoological institutions in the United States jumped in thereafter to develop captive reproduction protocols. This was a challenging task for these frogs, considering the unique conditions that they require to trigger an artificial reproductive season, along with the necessity of having to pre-plan the pairings of couples in order to maintain a high genetic diversity within the captive collection. But the efforts were fruitful, and today, a healthy captive population consisting more than a thousand individuals dispersed across 50 or so American and Canadian zoological institutions exists. The ultimate objective of this project, called Project Golden Frog, is to repopulate the natural habitat of the species once the factors leading to their extinction are controlled.

The Biodome, a proud collaborator

Since 2017, the Montreal Biodome has taken part in Project Golden Frog. and seven egg clutches have been laid over the past three years. Here, we proudly share with you a few images of the results. I also take this opportunity to congratulate Roxan Ouimet, Sylvain Ethier and Marisa Scrilatti, animal care technicians at the Montreal Biodome, for the excellent work that they accomplished for this project! Speaking on behalf of the Panamanian Golden frogs, I would like to say muchisimas gracias!

References :

  • Bittel, J. (2019). “On la pensait éteinte depuis 30 ans, la grenouille arlequin nuit étoilée signe son grand retour.” National Geographic, 18 déc.
  • Greshko, M. (2019). “Amphibian 'apocalypse' caused by most destructive pathogen ever.” National Geographic, 28 mars
  • La Marca, E., Lips, K. L., Lötters, S., Puschendorf, R. (2005). Catastrophic Population Declines and Extinctions in Neotropical Harlequin Frogs (Bufonidae: Atelopus). Biotropica 37(2):190–201
  • Lecumberry, M. (2017). “La Grenouille Dorée, bijou vivant du Panama, sauvée in-extremis.” Overblog, Sagapanama, 25 mai
  • Lips, K. L. (2016). Overview of chytrid emergence and impacts on amphibians. Philosophical Transactions B 371: 20150465
  • Poole, V. / NAIB (2006). Husbandry Manual Panamanian Golden Frog Atelopus zeteki, Second Edition.
  • Scheele, B. C., Pasmans, F., Skerratt, L. F., Berger, L., et al. (2019). Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity. Science 363(6434): 1459-1463
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