myobatrachidae

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The ‘Frog Glue’ of the Crucifix Frog 

This peculiar frog is an Australian endemic species that occurs in central inland New South Wales and the interior of southern Queensland. Its scientific name is Notaden bennettii (Myobatrachidae), and is better known as the Crucifix Frog or Holy Cross Frog because of the pattern of dark spots on its back resembling a cross.

Notaden bennettii is a fossorial frog, it means that is adapted to spend most of its life underground. They only emerge after heavy rains and breed in temporary pools.

Frogs of this species (and also of N. melanoscaphus and N. nichollsi)  produce an exudate, secreted by glands on their backs, that quickly sets into an adhesive and elastic material. They secrete the sticky material when they are provoked, probably in an attempt to deter potential predators.

The frogs typically live 1m underground in dried mud for nine months of the year. When they emerge are vulnerable to insect attacks and so a possible use of the exudate may be to jam the jaws of biting insects like ants, sticking them to the frog’s skin, which it later sheds and eats. The exudate sets rapidly as a yellow-colored tacky elastic solid, and sticks well even in the frog’s moist habitat.

Preliminary studies of this adhesive, which is biocompatible, have shown its several useful potential properties for medical applications.

References: [1] - [2] - [3]

Photo credit: ©paulhypnos  |  [Top]  -  [Bottom]

Locality: Australia

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Sudell’s Frog (Neobatrachus sudelli)

Also sometimes known as the “Painted Burrowing Frog”, a name also given to another member the genus Neobatrachus as well. Sudell’s frog is a species of Australian ground frog (Myobatrachidae) which is found on and west of the Great Dividing Range of New South Wales to western Victoria and southern Queensland as well as far eastern South Australia. Sudell’s frogs typically inhabit ponds, dams, ditches, and other areas of still water in woodland shrubland and even disturbed areas. They are also accomplished burrowers, spending large periods of time underground to avoid droughts. 

Classification

Animalia-Chordata-Amphibia-Anura-Myobatrachidae-Neobatrachus-N. sudelli

Image: LiquidGhoul

Holocene Extinction Month #18 – Southern Gastric-Brooding Frog

The southern gastric-brooding frog (Rheobatrachus silus) was one of only two known species of frog that incubated their offspring inside the stomach of the mother. (The other being the northern gastric-brooding frog, R. vitellinus, also recently extinct.) About 5.4cm long (2.1in), it was found only in a small area of mountainous rainforest in southeast Queensland, Australia.

After external fertilization, female gastric-brooding frogs would swallow their eggs. Each egg’s coating contained a chemical – prostaglandin E2 – which turned off production of stomach acids, allowing the tadpoles to develop without being digested. Incubation took six weeks, during which the mother went entirely without food and her stomach grew to fill most of her body cavity, until the fully metamorphosed froglets were finally “birthed” via vomiting.

Only discovered in the 1970s, the southern gastric-brooding frog’s habitat was disrupted by logging activity, invasive weeds, and feral pigs. It may also have been heavily affected by chytridiomycosis, a fungal disease threatening amphibian populations all over the world. The last sighting of the species was in either 1979 or 1981, depending on the source.

Embryos of the southern gastric-brooding frog were successfully cloned in early 2013. Although the embryos only survived for a few days, the “Lazarus Project” actually seems very promising, and sometime in the near future this frog could be the first species to be truly “brought back to life”.

Desert Spadefoot Toad (Notaden nichollsi) by Stephen Zozaya

“I have been waiting to see one of the 4 spadefoot toads (Notaden sp.) for ages now. I was thrilled when I stopped to check a frog on the road and it turned out to be a Notaden nichollsi. I was then fortunate enough to see about 300,000 more in the next 2 nights as I turned left and right to dodge them all while looking for geckos. I guessed I timed that right.”

Photographed near Windorah, Queensland, Australia.

Western Spotted Frog - Heleioporus albopunctatus

Heleioporus albopunctatus (Myobatrachidae) is a species of fat, globular burrowing frog, with granular skin, rather stubby limbs and toes with only rudiments of webbing. The body is chocolate-brown above; the back, head, sides and limbs are marked with scattered large white or yellow spots.

Endemic to Australia, this chubby frog is largely restricted to coast and ranges of south-western Australia.

References: [1] -[2]

Photo credit: ©Stephen Zozaya | Locality: Watheroo, Western Australia (2013)

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The extinct (and nearly resurrected) Southern Gastric Brooding Frog

Also known as Southern Platypus Frog, the Southern Gastric Brooding Frog, Rheobatrachus silus (Myobatrachidae) was a rare and extraordinary frog, and I say was because this species, endemic to Australia and restricted to south-east Queensland, was declared Extinct in 2002 because it has not been recorded in the wild since 1981, and extensive searches over the last 25 years have failed to locate this species. A terrible irony since this species was described only in 1972, but the world only took notice of it in 1974 when it was discovered how it reproduced.

Simply put, the mother frog converts her stomachs into a womb. She swallows her own eggs and stops making hydrochloric acid in her stomach to avoid digesting her own young. Around 20 to 25 tadpoles hatch inside her and the mucus from their gills continues to keep the acid at bay. While the tadpoles grow over the next six weeks, mum never eats. Her stomach bloats so much that her lungs collapse, forcing her to breathe through her skin. Eventually, she gives birth to her brood through “propulsive vomiting”, spewing them into the world as fully-formed froglets.

A few years ago a group of Australian scientists specialized in the so called De-Extinction research (the controversial process of creating an organism which is – or greatly resembles – a member of an extinct species), aptly named Lazarus projectdid the first experiments to resurrect this extinct species. They inserted DNA extracted from a frozen specimen of the bizarre gastric-brooding frog into the donor eggs of another species of living frog whose DNA had been deactivated by UV light, in a process similar to the technique used to create the cloned sheep Dolly. The eggs continued to grow into three-day-old embryos, known as blastulas. While the embryos had yet to develop into tadpoles, genetic tests revealed the dividing cells contained the DNA of the extinct frog.

They achieved the beginnings of a gastric brooding frog, but are a long way from even a simple tadpole. The Lazarus project haven’t brought back the gastric-brooding frog yet but they have developed a tool that can be useful in the future.

References: [1] - [2] - [3] - [4] - [5]

Illustration and Photo credits: ©Rafa Garabal/Artimalia

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