Oddity Ark #19 (199) Pumpkin Toadlet

We’re well into November now, with Shocktober now just a horrible worm-infested dream behind us. And so, it behoves me to add in a cute pallet cleanser, in this case a frog that fails at being a frog. Get ready to give this issue some sympathy ‘ah’s and don’t forget you can request an issue on any amazing animal, perplexing plants, fabulous fungi and magnificent paleofauna in the comments.

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Oddity Ark #19 (#199)

Kingdom: Animalia

Phylum: Chordata

Class: Amphibia

Order: Anura

Family: Brachycephalidae

Genus: Brachycephalus

Species:ephippium

Related Species: The pumpkin toadlet is one of over 35 species of frog known colloquially as ‘Saddleback Toads’(1).

Range: Pumpkin toadlets are only found in the Atlantic forests of Brazil between altitudes of 200 – 1250m.

IUCN Status: The pumpkin toadlet is listed as ‘Least Concern’ by ICUN.

Bad at being a Frog

The pumpkin toadlet is small frog, with an average body length of 15mm, making it among the largest of the saddleback toads. Due to their small size and the underdeveloped vestibular system, the pumpkin toadlet has trouble with its sense of balance, making it unable to detect changes in angular acceleration when jumping, and because of this many jumps end in crash landings (2). Because of this, pumpkin toadlets rarely jump, and much like the true toads, prefer to get around by walking. Due to their small size and the Due to their small size and the

Pumpkin toadlets, like all amphibians are obligate carnivores, feeding on small invertebrates such as springtails, pseudoscorpions and mites. Prey is spotted by visual stimuli as they pass the toadlet and are then grabbed by the mouth as the amphibian lunges forward. While small, pumpkin toadlets have few (if any) predators, with their bright orange skin warning potential attackers of their toxicity. Both the skin and the organs of the pumpkin toadlet contain tetrodotoxin (C₁₁H₁₇N₃O₈) and 11-oxotetrodotoxin (C₁₁H₁₇N₃O₉), the latter being five times more potent than the base tetrodotoxin (3), as well as a myriad of other neurotoxins.

Because of their underdeveloped vestibular system impacting their hearings, pumpkin toadlets are unable to hear the frequency at which they call at, effectively making them deaf to their own mating calls (4). It is speculated that, when males call, females are attracted to the pulsating of the vocal sack rather than the sound produced. Female pumpkin toadlets lay up to five eggs in the leaf litter, rolling them in detritus until the outer membrane is covered to prevent water loss [5]. Approximately two months later, the eggs hatch into miniature brown skinned adults, completely skipping the typical larval stage that most amphibians go through.

Five Fun Pumpkin Toadlet Facts

The bones of the pumpkin toadlet can be seen fluorescing under the skin of the frog when exposed to ultraviolet light (6).

It is speculated that at least some of these toxins found in the pumpkin toadlets skin are bioaccumulated from the prey the frogs feed on.

The frogs in the genus Brachycephalus have fused vertebral shields across their backs, giving them the colloquial name saddleback toads.

Despite being described as ‘saddleback toads’ the frogs in the genus Brachycephalus lack the Bidder’s organ, used for regulating sexual hormones, found within toads in the genus Bufo. Because of this they are considered to be frogs.

The flea frog (Brachycephalus hermogenesi) is not only the smallest member of the saddleback toads at a length of 7.9mm but is also the smallest frog species in the Americas.

References

1. www.arkive.com

2. "Here's why pumpkin toadlets are such clumsy jumpers". Science News. 2022-06-15.

3. Pires, Osmindo R.; Sebben, Antonio; Schwartz, Elisabeth Ferroni; Bloch, Carlos; Morales, Rodrigo A. V.; Schwartz, Carlos A. (October 2003). "The occurrence of 11-oxotetrodotoxin, a rare tetrodotoxin analogue, in the brachycephalidae frog Brachycephalus ephippium". Toxicon. 42 (5): 563–566.

4. Goutte, S.; et al. (2017). "Evidence of auditory insensitivity to vocalization frequencies in two frogs". Scientific Reports. 7 (1)

5. Pombal Jr., J.P.; I. Sazima; C.F.B. Haddad (1994). "Breeding Behavior of the Pumpkin Toadlet, Brachycephalus ephippium (Brachycephalidae)". Journal of Herpetology. 28 (4): 516–519

6. Sandra Goutte; Matthew J. Mason; Marta M. Antoniazzi; Carlos Jared; Didier Merle; Lilian Cazes; Luís Felipe Toledo; Hanane el-Hafci; Stéphane Pallu; Hugues Portier; Stefan Schramm; Pierre Gueriau; Mathieu Thoury (2019). "Intense bone fluorescence reveals hidden patterns in pumpkin toadlets". Scientific Reports. 9 (1): 5388.

Picture Credits

1. moss-button-frog-1024x767-1.jpg (1024×767) (myanimals.com)

2. OIP.oo-MatHogncTsD7JqV9umAHaFj (474×355) (bing.com)

3. Tiny-Brazilian-frogs-found-to-exhibit-fluorescent-patterns-831x640.png (831×640) (earth.com)

4. 9e8a00f2e1e20efb7d487b9c9889fab4.jpg (320×233) (pinimg.com)

Next week's issue is one of Impurest Cheese's favourite birds and was what she had planned for Issue 200 of IGTA. If you want to see more amazing animals and plants, please check out the Oddity Arkive for past issues. And if you want even more animals, please check out dearly departed Impurest Cheese’s Guide to Animals which can be found here, or on the blog of long-suffering ecology intern @ficopedia

@cbishop, @batkevin74, @mrmonster, @lemillion, @shoto_todoroki and @spareheadone.

A frog that gets a D at being a frog.

No tadpoles :(

@spareheadone: Thanks for the comment, the lack of a larval stage is partially why the pumpkin toadlet gets a D at being a frog, the other reasons having a 33-50% crash rate when jumping and being deaf to its own calls.

At least it’s horribly toxic if you eat it, that hives with being an amphibian.

Being so toxic, are they any relation to poison dart frogs?

@cbishop: Completely different families and two different toxin groups. Since all amphibians are poisonous to some extent and they live in the same area it’s likely a combination of shared distant ancestry and the same environmental pressures that fostered such extreme levels of toxcicity.