Monthly Archives: August 2011

WEIRD & FASCINATING CREATURES: Certain species of frog give birth to young through the mouth

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Image: A female gastric-brooding frog’s young develop within her stomach, and she gives birth, or regurgitates the froglets, through the mouth.

Perhaps the Surinam toad doesn’t employ the weirdest mode of reproduction amongst the frogs and toads. The female gastric-brooding frog or the platypus frog (Rheobatrachus spp.) of Australia “brood[s her] young within [her] stomach and give[s] birth through the mouth.” It’s definitely a unique mode of reproduction.

Sadly, however, gastric-brooding frogs are probably extinct. Their unusual mode of reproduction is known only from some photographs or written accounts of observations, so the chance exists that no other living human will be able to witness one of nature’s most extraordinary events.  I don’t believe that video exists showing the female frogs give birth through the mouth.  However, if you know of video, then please share the information.

There were two known species of gastric-brooding frogs —  Rheobatrachus silus, or the Southern gastric-brooding frog, and Rheobatrachus vitellinus, or the Eungella gastric-brooding frog — and both species are presumed extinct. It is unknown why these frogs disappeared but chytridiomycosis, in addition to habitat destruction, is suspected. Via the International Union for Conservation of Nature (IUCN):

The reason(s) for the disappearance of this species remains unknown (Tyler and Davies 1985b). Populations were present in logged catchments between 1972 and 1979. Although the species persisted in the streams during these activities, the effects of timber harvesting on this aquatic species were never investigated. Its habitat is currently threatened by feral pigs, invasion of weeds (especially mistflower Ageratina riparia), and altered flow and water quality due to upstream disturbances (Hines, Mahony and McDonald 1999). However, from what is known from similar declines and disappearances elsewhere in the world, the disease chytridiomycosis must be suspected.

However, a new, efficient automated system, which seems to be exceptionally accurate, may locate any gastric-brooding frogs that might still be in existence by listening for them. Via ABC Science Online:

Citizen science and computer software are being harnessed as a low-cost way of tracking Australian native bird species in order to monitor environmental change.

The Queensland University of Technology software is also being used on the frontline in the battle to stop cane toads marching on to Groote Eylandt in the Northern Territory.

The program uses automatic acoustic sensors, voice recognition technology and expert birdwatchers to reduce the number of hours ecologists have to spend in the field observing wildlife.

Researcher Jason Wimmer, a PhD student, says experiments show the automatic system is actually more effective in capturing the presence or absence of birds than standard observation.

Under the project, sensors are placed in the bush to record environmental sounds that are then transmitted to an online digital library.

To overcome the need to sit through hours of recordings to listen for bird sounds, Wimmer and his team developed a software program to filter the audio and identify potential bird noises.

.       .       .

Wimmer says the potential of the automatic system was highlighted by a 2 am recording of the call of a rarely sighted species, Lewin’s Rail (Lewinia pectoralis).

“That is just one example of the impact this system can have,” he says.

The system is also going to be used to find the Gastric Brooding Frog, a native frog that has not been seen for 20 years with sensors to be placed in the Conondale Range, north-west of Brisbane.

Wimmer says the technology is also helping protect native quolls on Groote Eylandt from eating cane toads. The island is currently free of cane toads.

“We’ve put in sensors as an early-warning system for cane toads,” he says. “The sensors are all 3G (mobile phone)-based and timed to record and analyse data automatically.”

The sensor turns on every 30 minutes and if it hears the distinctive canetoad calls is programmed to send SMS alerts to various people.

Continue reading this article at ABC Science Online.

To prevent digestive juices from destroying the eggs and tadpoles, both the eggs and tadpoles produced or were associated with a “substance [that] had the ability to turn off the production of hydrochloric acid in the [frog's] stomach.” After some time, developing within their mother’s stomach, fully-formed froglets emerge from the mother’s mouth (though some accounts note that one of the species gave birth to tadpoles — not fully-formed froglets). More on the reproductive habits of Rheobatrachus silus via the IUCN:

Females brood young within the stomach and give birth through the mouth (Tyler and Carter 1982). Fertilized eggs or early stage larvae are presumably swallowed by the female and complete their development in the stomach (Tyler and Carter 1982). The number of eggs in gravid females (approximately 40) exceeds the number of juveniles found to occur in the stomach (21-26) (Tyler 1989). It is not known whether or not the excess eggs are digested by the female or whether or not they are simply not swallowed (Tyler 1989). The production of hydrochloric acid in the stomach of the female ceases during brooding (Tyler et al. 1983). Tadpoles develop in a manner similar to the aquatic tadpoles of other species though, as they feed off egg yolk, the labial teeth are absent and the intestines form at a later stage of development (Tyler 1989). After 6-7 weeks the females give birth to up to 25 young (Tyler and Davies 1983a). Young emerge from the female’s mouth as fully formed frogs and after four days the digestive tract returns to normal and the female recommences feeding (Tyler and Davies 1983b). Ingram (1983) reported minimum brooding periods from two individuals of 36 and 43 days and suggested that the duration was such that females were unlikely to breed twice in one season.

More on the reproductive habits of Rheobatrachus vitellinus via the IUCN:

It is an aquatic species largely restricted to the shallow section of fast-flowing creeks and streams in rainforest. It is one of only two known species to brood its offspring within its stomach. Females deposited their eggs, and then swallowed them. While in the stomach, tadpoles excreted some form of enzyme that inhibited the female’s gastric digestion, and then proceded to develop into fully formed froglets. The froglets were then regurgitated through the female’s mouth.

More via Vitt and Caldwell (2009):

In the gastric brooding frogs, Rheobatrachus silus and Rheobatrachus vitellinus, brooding of eggs and/or larvae occurs in the stomach of the female; in one species, froglets emerge after metamorphosis, whereas in the other species, tadpoles are released by the female. Development in those frogs is supported entirely by yolk contained in the eggs (Crump, 1995; McDonald and Tyler, 1984).  In contrast to Rhinoderma rufum, male Rhinoderma darwinii brood their tadpoles in their vocal sacs until metamorphosis occurs (Crump, 1995).

I couldn’t find information on whether the females of either species of gastric-brooding frogs stop feeding during gestation. However, it seems that more eggs were typically produced and swallowed than the number of froglets that were actually hatched or regurgitated by the female, so either the females digested some or all of the eggs, or the tadpoles and froglets consumed some or all of the unfertilized eggs while in the stomach, or perhaps some combination of both behaviors existed. There must have been some mechanism in place to utilize or dispose of unfertilized or bad eggs. Perhaps, the tadpoles practiced cannibalization as well. Tadpoles are known to practice cannibalism.

Video (this video plays automatically): In this video, a Southern gastric-brooding frog swims about a tank, and there’s a still image showing a froglet in adult’s mouth. Via ARKive

Image of Darwin’s Frog via

However, one species of frog, still in existence, uses a somewhat similar mode of reproduction to the gastric-brooding frogs of Australia. Darwin’s frog (Rhinoderma darwinii) is a species that’s “endemic to the austral forest of Chile and Argentina.” The species is considered vulnerable, and its population is in decline. Via the IUCN:

Recent surveys within the range of Rhinoderma darwinii in Chile reveal that some populations (including those in national parks and other preserved areas) have disappeared entirely (M. Crump and A. Veloso pers. comm.). In other areas, the density of frogs is much lower than 10 or 20 years ago (M. Crump pers. comm.). Forestry operations have destroyed large areas where northern populations were found. However, it was still abundant in at least some southern Chilean localities in 2003; indeed, it appears that the species reaches its highest densities in regions of the Archipelago, where habitat disturbance is minimal (M. Crump pers. comm.). In Argentina, this is a scarce species and appears to have declined at one site (Puerto Blest, Río Negro Province) during the past 50 years.

.       .       .

In the north, the main threats are drought and pine forestry, while in the south it is clear-cutting of forest. Declines that have taken place in suitable habitat could be the result of other threats, such as climate change or disease (possibly chytridiomycosis, although this normally impacts species that are associated with water, and it has not previously been reported from Chile).

Instead of gestation taking place within the female’s stomach, as with the gastric-brooding frogs, the male Darwin’s frog “ingest[s] the eggs and incubate[s] them in vocal sacs.” Six weeks later, the male frog literally gives birth to fully-formed froglets through the mouth (though Rhinoderma rufum releases tadpoles, instead of froglets, from its vocal sacs) — making the male frogs of this species “the only other member of the animal kingdom that exhibits anything close [to] the seahorse [and their kin], where the male carries the babies in a brood pouch.” More on Rhinoderma rufum via Wikipedia:

This species of frog exhibits a highly unusual form of parental care in that the tadpoles spend part of their life developing in the vocal sac of their father, where they ‘hitch a ride’ to a pool of water in their father’s vocal sac where they complete their development from the tadpole to the frog form.

Video: In this video, it’s possible to see the movement of tadpoles within the vocal sacs of the Darwin’s frog.

Video (this video plays automatically): A male Darwin’s frog releases fully-formed froglets from his vocal sac. Via the BBC.

WEIRD & FASCINATING CREATURES: Videos illustrate the Surinam toad’s unique mode of reproduction

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Image via dinoboy on Flickr

The Surinam toad could either be considered remarkable or disgusting (or maybe both). This species of toad is a unique example of the extraordinary reproductive techniques that some species have evolved to help ensure the survival of their young.

During mating, instead of releasing eggs and sperm directly into their aquatic environment and abandoning the eggs to fate, the male and female toads, through amplexus and complex movements, manage to embed the fertilized eggs into the dorsum of the female, where they develop. Some time in between two to four months, presumably depending on environmental conditions, fully-formed toadlets emerge from the pockets of the female’s dorsum.

The Surinam toad also utilizes some remarkable camouflage. Both its coloration and the shape of its body are reminiscent of a dead leaf, which certainly helps it to avoid predation as it navigates its aquatic environment. More on the frog’s bizarre lifecycle via Wikipedia:

Surinam toads are most well-known for their remarkable reproductive habits. Unlike the majority of toads, the males of this species cannot attract mates with croaks and other sounds often associated with these aquatic animals. Instead they produce a sharp clicking sound by snapping the hyoid bone in their throat. The partners rise from the floor while in amplexus and flip through the water in arcs. During each arc, the female releases 3-10 eggs, which get embedded in the skin on her back by the male’s movements. After implantation the eggs sink into the skin and form pockets over a period of several days, eventually taking on the appearance of an irregular honeycomb. The larvae develop through the tadpole stage inside these pockets, eventually emerging from the mother’s back as fully developed toads, though they are less than an inch long (2 cm). Once they have emerged from their mother’s back, the toads begin a largely solitary life.

Video: A female Surinam toad with eggs embedded into her dorsum.

Video: This video shows toadlets emerging from their mother’s dorsum.

Video: This video, in Japanese, shows the complete lifecycle of the Surinam toad. The video also shows the horror of onlookers, or their hysterical reactions rather, as they watch the toadlets emerge from their mother’s dorsum.

Video: Another video that shows toadlets emerging from pockets on their mother’s dorsum.

Video: Toadlets emerge from a Surinam toad’s dorsum at the Audubon Zoo.

REDISCOVERED SPECIES: Glow-in-the-dark mushroom rediscovered after almost 170 years of absence

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Neonothopanus gardneri image found here

A species of bioluminescent fungi, Neonothopanus gardneri, which hasn’t been seen in almost 170 years, has been rediscovered in Brazil. According to the USA Today, it is “one of the most strongly bioluminescent mushrooms known.” More via USA Today:

Glowing fungi aren’t all that unusual in nature, there are 71 known species. But “this one is incredibly bright for a luminescent mushroom,” says Dennis Desjardin, a professor of evolutionary biology at San Francisco State University who researches fungi. “It glows more brightly than almost all other luminescent mushrooms.”

While most glowing fungi are either tiny or faint, these mushrooms emit a greenish light strong enough “that if you were in a dark room and you put one on a newspaper, you’d be able to read the words,” says Desjardin.

The last time scientists encountered this specific glow-in-the-dark mushroom was in 1840, when English botanist George Gardner saw some boys playing with a glowing object in the streets of Vila de Natividad, a village in the Goiás state in central Brazil.

Gardner sent examples of it to researchers at the Royal Botanical Gardens, Kew in England. They confirmed it was an unknown species and named it for him, calling it Agaricus gardneri.

After that there were no more reports of it.

Brazilian chemist, Cassius Stevani first heard of the existence of these mushrooms in 2001 or 2002, he said via email from Brazil.

But it wasn’t until February of 2005 that he got more data, from scientists Patricia Izar from São Paulo University in Brazil and Dorothy Fragaszy of the University of Georgia in Athens.

They were studying a band of monkeys in Brazil’s Piauí State and their use of rocks at tools to break nuts. One day they returned to the camp where “they found some mushrooms growing on the base of palms,” Stevani says.

.       .       .

The group has been looking at the chemical pathways that allow these mushrooms to produce light, a mechanism that is still somewhat mysterious. The newly re-discovered mushroom also allowed them to make chemical comparisons between the four major lineages of mushrooms that are bioluminescent.

Scientists have been trying to understand whether the ability to glow evolved four times or just once, back when these distantly-related mushrooms had a common ancestor. Chemical analysis showed that they share much of the chemistry for producing light, “which suggests the pathway must have evolved early on ,” says Desjardin.

Only 71 species of fungi are bioluminescent, out of the 100,000 known species.

Why certain fungi glow in the dark is another unknown. One theory is that insects attracted to the glow help carry the mushrooms’ spores farther afield. Another is that the light attracts predatory insects that in turn eat insects that snack on the fungus.

One animal that doesn’t eat Neonothopanus gardneri is humans. It’s in a family of mushrooms known to be responsible for poisonings worldwide, says Desjardin.

Continue reading this article at the USA Today.

More images of other species of bioluminescent fungi from around the world:

Panellus stipticus is a cosmopolitan species of bioluminescent mushroom, which is found in North America and around other parts of the world. Image via

Panellus stipticus. Image via

A species of Mycena glowing at night in eastern Australia. Image via Smoken Mirror on Flickr

Image via Christina’s Play Place on Flickr

Image via Christina’s Play Place on Flickr

Mycena sp. Image via Smoken Mirror on Flickr

WEATHER: July 2011 heatwave results in almost 9000 heat records broken or tied

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Via Gizmodo and The Daily:

Last month almost 9,000 daily heat records were broken or tied across the country. This includes 2,755 highest maximum temperatures and 6,171 highest minimum temperatures (nighttime records).

Here’s a high-resolution map of the record-breaking heatwave from July via NOAA’s Environmental Visualization Laboratory:

The record heat is also affecting water quality, causing pavements to explode, causing railroad rails to expand and buckle, and causing insects to invade homes in search of shelter and water.

POLITICS: Did Republican shenanigans result in the United States’ credit downgrade?

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Image via

It appears that the manner in which the Republicans steered or conducted the debt-ceiling debate, or given the fact that Republicans refuse to end the crippling Bush tax cuts or implement measures to raise revenue for the U.S. government, resulted in the United States’ credit downgrade by Standard & Poor’s. Also, the Republican Party’s refusal to work with President Obama, or consider his policies, has certainly played a part in the overall uneasy attitude towards Congress regarding its inability to manage the U.S. economy, to implement policies to spur job growth, or to implement legislation to curb the United States’ debt. Also, the Tea Party, through it’s influence and inability to grasp the important role that government is supposed to play in managing the well-being of society, has been a major factor in generating political insanity and economic uncertainty. Via NationalJournal.com:

The big new element on Friday was an official outside recognition that U.S. creditworthiness is being undermined by a new factor: political insanity. S&P didn’t base its downgrade on a change in the U.S. fiscal and economic outlook. It based it on the political game of chicken over the debt ceiling, a game that Republicans initiated and pushed to the limit, and on a growing gloom about the partisan deadlock.   Part of S&P’s gloom, moreover, stemmed explicitly from what a new assessment of the GOP’s ability to block any and all tax increases.

S&P was remarkably blunt that its downgrade was mostly about heightened political risks:  “The political brinksmanship of recent months highlights what we see as America’s governance and policymaking becoming less stable, less effective, and less predictable than what we previously believed,” it said.

(TEXT: Politicians React to Downgrade)

“The statutory debt ceiling and the threat of default have become political bargaining chips in the debate over fiscal policy. Despite this year’s wide-ranging debate, in our view, the differences between political parties have proven to be extraordinarily difficult to bridge, and, as we see it, the resulting agreement fell well short of the comprehensive fiscal consolidation program that some proponents had envisaged until quite recently.”

To be sure, S&P didn’t specifically single out Republicans. It criticized the overall $2.4 trillion deal as too limited, and it implicitly criticized both political parties for refusing to tackle their sacred cows – entitlements, in the case of Democrats; tax increases in the case of Republicans.

But it’s hard to read the S&P analysis as anything other than a blast at Republicans.  In denouncing the threat of default as a “bargaining chip,” the agency was saying that the GOP strategy had shaken its confidence.  Though S&P didn’t mention it, the agency must have been unnerved by the number of Republicans who insisted that it would be fine to blow through the debt ceiling and provoke a default.

As many other analysts have noted, the deficit-reduction deal wouldn’t stop debt from climbing faster than the nation’s GDP over the next decade.   It warned that the government’s publicly-held debt would climb from 74 percent of GDP at the end of this year to 79 percent by the end of 2011.

But one reason S&P said it had become more gloomy was that it had revised its assumptions about the most likely course of fiscal policy. In previous projections, it said, its “base case scenario” had assumed that Bush tax cuts for the wealthy would expire at the end of 2012, while tax cuts for families earning less than $250,000 a year would be extended.  That, it said, would have reduced deficits about $950 billion over ten years.

But the new S&P base case assumes that Congress extends all the Bush tax cuts.   “We have changed our assumption on this because the majority of Republicans in Congress continue to resist any measure that would raise revenues, a position we believe Congress reinforced by passing the act,” S&P said.