Category Archives: Amphibians

Frogs, toads, newts, etc.

Coelacanth DNA and tetrapod evolution

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This video says about itself:

DNA From Fish May Explain How Feet Evolved From Fins

18 April 2013

Decoding the coelacanth fish genome has put scientists closer to reconstructing how animal ancestors crawled out of the sea 400 million years ago.

By Philip Guelpa:

Genome sequencing of “living fossil” fish sheds light on the evolution of land animals

30 April 2013

In a newly published article in the scientific journal Nature (496, 311–316), scientists report a significant step in the understanding of the evolutionary process that led certain ancient fish to develop limbs and emerge onto dry land, becoming the ancestors of all amphibians, reptiles, birds, and mammals. This transition is one of the most important in the development of life on earth.

The new research is based on the decoding of the genome of a so-called “living fossil” fish, the “coelacanth” (pronounced SEE-luh-canth). This group of fishes, known from fossils dating as far back as 400 million years ago, was long thought to have gone extinct 70 million years ago, in the Late Cretaceous Era. However, the discovery of a living specimen in the West Indian Ocean off of South Africa in 1938 demonstrated that a reclusive population still survived. More recently, a second species of living coelacanth, both belonging to the genus Latimeria, was discovered in Indonesia.

Coelacanths have been colloquially known as living fossils because of their close resemblance, at least outwardly, to fossil specimens dating back tens and even hundreds of millions of years. But perhaps the most interesting aspect of these fish is their apparent close evolutionary relationship to the first land vertebrates.

It has long been thought, based on paleontological and anatomical evidence, that all tetrapods (four-limbed, vertebrate animals—amphibians, reptiles, birds, and mammals) evolved, somewhere in the neighborhood of 400 million years ago, from fish closely resembling the now mostly extinct group of lobe-finned fish belonging to the class Sarcopterygia.

Lobe-finned fish have a well-developed bony skeleton inside their fins, in contrast to the common ray-finned (teleost) fish. Living representatives of this lineage include lungfish, which are actually able to breathe air with lungs that are homologous (have the same genetic origin) as those of tetrapods, and the coelacanth.

Basic anatomical similarities between the skeletal structures in the fins of lobe-finned fish and the limbs of tetrapods strongly suggested an evolutionary link. However, the details of the mechanism for the transformation of fins into limbs had yet to be understood. The newly reported research begins to fill in that gap.

The technique of DNA sequencing, which in recent years has permitted the decoding of the human genome and those of a growing number of other species, has now been used to document the coelacanth’s DNA sequence. Among the resulting discoveries is a genetic mechanism that controls the growth of both the lobe-shaped fins in the coelacanth and of limbs in tetrapods.

Scientists have long wondered whether lungfish or coelacanths were more closely related to tetrapods. In other words, which group is closer to the common ancestor of the earliest vertebrate animals to walk on land? Genetic sequencing holds the potential to answer such questions. Unfortunately, lungfish have an incredibly large genome, which cannot be effectively sequenced by existing methods. It should be noted that the size of a species’ genome has no necessary correlation with the complexity of the organism, due to duplications of DNA sequences and other “baggage” accumulated during the course of evolution, which is not a particularly neat process.

Despite this, the scientific team whose research was published in Nature was able to decode segments of the lungfish genome and compare it to their newly completed full coelacanth sequence as well as to those from a sample of tetrapods. This permitted the conclusion that lungfish are more closely related to tetrapods than are coelacanths. Nevertheless, since the two groups of lobe-finned fish are closely related to each other, knowledge of the coelacanth genome is revealing much regarding the evolution of the first land-dwelling vertebrates.

The first and highly necessary step for the investigators was to determine whether the living coelacanth had evolved only very slowly from its ancestors millions of years ago, as suggested by its ancient outward appearance. This was critically important because the relevance of further analysis would depend on whether the genetic patterns observed in the modern coelacanth could be expected to resemble those of the common ancestor of lobe-finned fish and tetrapods.

The results of this analysis indicate that coelacanths have evolved very slowly as opposed to a number of other species to which they were compared. Many factors influence the rate of evolution in any given lineage of organisms. Evolution is a dialectical interaction between a species and all the elements of its environment. A stable environment means that there is little selective pressure that would prompt adaptive changes. The relatively static environment in which the surviving coelacanths live, and a lack of predators, are likely to have been factors in their slow evolution.

With that understanding, the researchers focused on studying genes that control the expression of structural genes (i.e., genes that build body parts). Such control genes regulate such factors as the degree, rate, and timing of expression of the structural genes.

Among the categories of regulatory genes identified as being newly evolved in tetrapods (that did not exist in the ancestral lobe-finned fish) were ones associated with sensing of chemicals, through taste and smell, driven by the need to more fully perceive the complex terrestrial environment.

Other categories of new control genes include those related to radial pattern formation (body form), hind limb development, kidney development, and the immune system. Again, all of these would have been important in evolutionary adaptation to the new constraints and opportunities of terrestrial existence.

In all, the team identified over 44,000 control genes that evolved after the appearance of tetrapods.

The researchers paid particular attention to the genetic control of the development of hands and feet by comparing genes of teleost (ray-finned) fishes, coelacanths, and tetrapods. They found a specific gene sequence that is common to the latter two, but not found in the former. This sequence was identified as affecting limb development. Experimental insertion of the coelacanth genes into mouse embryos demonstrated that they could provide much of the regulation needed to produce tetrapod limbs, thus demonstrating that this gene complex existed in lobe-finned fishes and was repurposed in the evolution of land animals.

Also identified was a gene in coelacanths that appears later to have become important in the development of the mammalian placenta. Coelacanths give birth to live young which develop inside the mother’s body, but don’t receive direct nourishment from the mother during gestation, as is the case with placental mammals.

The research reported by this team demonstrates the great power and potential of genetic sequencing in helping to elucidate the patterns and mechanisms of biological evolution, complimenting evidence from the fossil record. In a broader sense, this work shows that biological evolution is a process that can be objectively studied and understood as part of the development of the material world.

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Toads mating season, video

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This video shows a female Eurasian toad with six males during the mating season.

The video was recorded on 14 April 2013 by Dick Schinkel from the Netherlands.

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International conservation award winners announced

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This video says about herself:

In 2012 a team of young conservationists from Kenya were awarded a CLP Future Conservationist Award to carry out scientific research on blue and black marlins and raise awareness of their plight. Team leader, Nelly Kadagi, recently attended the CLP’s international training course and tells about her experience in the Canadian Rockies.

From BirdLife:

2013 Conservation Leadership Programme awards winners announced!

Wed, Apr 10, 2013

The Conservation Leadership Programme (CLP) has announced this year’s 28 award-winning projects in 22 different countries, worth a total of $470,000.

“For many awardees, this is the first time that they have received funding to manage their own conservation projects so it’s a great boost in their careers. This year, for the first time, we’ll be supporting people in Afghanistan, Bhutan, Cape Verde, Moldova and Samoa to carry out their work,” said Kiragu Mwangi, BirdLife’s CLP Programme Manager.

This year’s projects are extremely diverse from Food Resource Evaluation in Chinese Snow Leopards to Saving the Endangered Giant West African Squeaker Frog in Ghana. One of the bird projects focuses on the little-known Tooth-billed Pigeon from Samoa, also known as the ‘little dodo’ due to its resemblance to its famous namesake.

However, one thing is the same for all projects. The chance to get access to conservation expertise and receive training.

All award-winning team members will become part of the CLP alumni network that supports approximately 3,500 conservation leaders. The network offers an opportunity for alumni to share and learn from each other as they deliver conservation outcomes in often challenging and isolated environments.

“Through this programme, we are building the capabilities of future conservation leaders and providing them with knowledge, skills and experience to address the most pressing conservation issues of our time”, said Kiragu.

Alumni members also receive access to additional grants, mentoring from CLP staff and training. A representative from each award-winning team will take part in CLP’s two-week Conservation Leadership & Management Training Workshop in June 2013 at a remote ecological research station in the foothills of the Canadian Rockies.

Eight of the 2013 project teams working on diverse threatened species of birds, plants and sharks will be mentored by BirdLife partners in Argentina, Bolivia, Cambodia, Kazakhstan, Moldova, Nepal, Paraguay and Zimbabwe.

The CLP has supported 530 projects since the programme’s inception in 1985.

The CLP is a partnership of BirdLife International, Conservation International, the Wildlife Conservation Society and Fauna & Flora International.

Full list

Future Conservationist Awards (up to $15,000)

Wildlife Survey in a Proposed Protected Area in Afghanistan
Saving the Endangered Marsupial Frogs in Yungas Forests of Argentina
Involving Anglers As Key Stakeholders in a Shark Conservation Programme, Argentina
Conserving Endangered Frog Species in Somuncura Plateau, Argentina.
Ecological and Distribution Assessment of Hicatee in Southern Belize
Hornbills: Connecting Environment, Economy and Culture in Bhutan
Conserving Quirusillas Reserve: a Key Area for the Alder Amazon, Bolivia
Conservation of the Critically Endangered Bolivian Frog Psychrophrynella illimani
Conservational Ecology of Giant Ibis in Western Siem Pang Iba, Cambodia
Integrative Conservation of the Terras Salgadas, Cape Verde
Migration Corridor and Habitat Survey in Xia’Erxili, China
Food Resource Evaluation for Snow Leopards, China
Participatory Conservation of the Critically Endangered Ecuadorian Brown-Headed Spider Monkey, Ecuador
Saving the Endangered Giant West African Squeaker Frog, Ghana
Monitoring Key Sites for White-Headed Duck in Kazakhstan
Initiating Conservation of New Hog Deer Population, Myanmar
Enhancing Community-Based Vulture Conservation in Western Lowland of Nepal
Ecology and Conservation of Ganges River Dolphin in Karnali Nepal
Reforestation with Native Species in the Dry Lands of Panama
Population Status Assessment and Conservation Measures of Butia marmorii Palm, Paraguay
Monitoring Important Bird Areas in Moldova to Improve Conservation Management
European Ground Squirrel Population from Eastern Romania
The Samoan “Dodo”: Saving the Manumea
Community-Based Conservation of Sea Turtles on Kolombangara, Solomon Islands

Follow-up Awards ($25,000)

Conservation of the Critically Endangered Togo Slippery Frog in Ghana
On-going Protection of Red Siskins in South Rupununi, Guyana
Scaling-up Mitigation of Human-Crane Conflict in Driefontein Grasslands, Zimbabwe

Leadership Awards ($50,000)

Improving the Community-Based Conservation of Lake Kuyucuk Ramsar Site, Turkey

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Mandarin duck eats frog, video

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This is a video about a female mandarin duck in a pond near Putten in the Netherlands. after the meal, she swims with her partner.

The maker of the video is Annie Goodschalk-Visch.

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Amphibian mothers feed young with their skins, new discovery

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Young Microcaecilia dermatophaga caecilians eating their mother's skin, photo: Emma Sherratt et al., PLoS ONE

From PLOS ONE:

A New Species of Skin-Feeding Caecilian and the First Report of Reproductive Mode in Microcaecilia (Amphibia: Gymnophiona: Siphonopidae)

Mark Wilkinson, Emma Sherratt, Fausto Starace, David J. Gower

Abstract

A new species of siphonopid caecilian, Microcaecilia dermatophaga sp. nov., is described based on nine specimens from French Guiana. The new species is the first new caecilian to be described from French Guiana for more than 150 years. It differs from all other Microcaecilia in having fewer secondary annular grooves and/or in lacking a transverse groove on the dorsum of the first collar. Observations of oviparity and of extended parental care in M. dermatophaga are the first reproductive mode data for any species of the genus. Microcaecilia dermatophaga is the third species, and represents the third genus, for which there has been direct observation of young animals feeding on the skin of their attending mother. The species is named for this maternal dermatophagy, which is hypothesised to be characteristic of the Siphonopidae.

Introduction

Kupfer et al. [1] discovered a novel form of extended parental care in the oviparous African herpelid caecilian Boulengerula taitanus in which altricial hatchlings feed upon the modified and lipid-rich outer layer of the skin of their attending mothers using a specialised deciduous juvenile dentition.

Subsequently, Wilkinson et al. [2] reported the putatively homologous behaviour and associated morphological and physiological features of maternal dermatophagy in a second species of caecilian, the Neotropical siphonopid Siphonops annulatus. Because these two species of skin-feeding caecilians are not particularly closely related and represent lineages that have been separated for more than 100 million years, Wilkinson et al. [2] suggested that skin feeding was a relatively ancient trait and predicted that it would prove to be more widespread among caecilians.

The Neotropical siphonopid genus Microcaecilia Taylor, 1968 includes eight previously described nominal species of relatively small caecilians with heavily ossified, stegokrotaphic skulls, and small eyes that are covered with bone [3] which suggest they are dedicated burrowers. Very little is known of their biology and there are no previous reports of the reproductive biology of any Microcaecilia. Here we describe a new species of Microcaecilia from French Guiana. Observations of reproduction in captivity reveal that this is a third caecilian species known from direct observation to practice maternal dermatophagy. The species is identified as a member of the Siphonopidae on the basis of being an oviparous caecilian with imperforate stapes and no inner mandibular teeth, and as a Microcaecilia on the basis of having eyes under bone, tentacular apertures closer to the eyes than the nares, and no diastemata between the vomerine and palatine teeth [4].

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Australian extinct frog back from the dead

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This video from Australia says about itself:

Mar 16, 2013

In a world first, a team of Australian scientists has taken the first major step in bringing the gastric brooding frog back to life.

Sarah Clarke reports.

From Australian Geographic:

Cloning brings extinct frog back from dead

By: Mischa Vickas | March-19-2013

Frozen tissue has allowed the bizarre gastric brooding frog – which gives birth via its mouth – to rise from the dead.

IT’S NOT EXACTLY Jurassic Park – not yet anyway – but Australian researchers have briefly revived an extinct species using frozen tissue and cloning technology to produce a live embryo.

“We are watching Lazarus arise from the dead, step by exciting step,” says Professor Mike Archer, a palaeobiologist at the University of New South Wales in Sydney, who led the project.

After the accidental discovery of frozen frog tissue several years ago his team were able to attempt cloning to bring the lost species back, says Mike. Though the embryos did not survive to adulthood, this represents the first time an extinct species has been revived.

Bringing extinct animals back from the dead

“The implications for other extinct and declining species are huge,” says Dr Simon Clulow, a biologist at the University of Newcastle who took part in the research. He says the feat opens up avenues for reviving other lost creatures, such as the Tasmanian tiger.

Queensland’s southern gastric-brooding frog, was one of two related species that swallowed its eggs and incubated tadpoles in its stomach, before giving birth to fully formed froglets via its mouth. Along with the northern gastric brooding frog it went extinct in the mid 1980s.

For the project, the experts inserted a dead cell nucleus of the southern gastric-brooding frog (Rheobatrachus silus) into the living donor egg of a related species, the great barred frog. The researchers first ensured that all existing genetic material was removed from the donor egg.

Frog gives birth through its mouth

The researchers managed to produce embryos – clumps of cells that survived for a few days.

“We’re increasingly confident that the hurdles ahead are technological and not biological and that we will succeed,” says Mike. “Importantly, we’ve demonstrated already the great promise this technology has as a conservation tool when hundreds of the world’s amphibian species are in catastrophic decline.”

The reason why the researchers chose the gastric-brooding frog, discovered near Brisbane in 1973, was because of its “unique and amazing evolution,” says Simon, who is an Australian Geographic Society sponsored researcher.

“The gastric-brooding frog evolved some of the most incredible strategies for reproductive success that have ever been observed in Australia, or indeed the world,” he says.

The reversal of extinction?

Simon argues that the research highlights the need for Australia to develop a bank of genetic material so that if the technology proves itself, future species extinctions can be avoided.

Half of all amphibians are in decline and 30 per cent are faced with extinction, largely as a result of human activity, says Simon.

The results of the project were presented in the US on Friday at TED conference for researchers discussing the possibility of bringing other extinct species back, including the woolly mammoth, the moa and the dodo.

Over the last decade other projects have looked at sequencing the genome of the Tasmanian tiger, and even reviving it using tissue from museum specimens, but they have been scuppered by technical or financial hurdles.

See also here.

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Chytrid fungus threatening amphibians

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This video from the USA says about itself:

Western Toad and Chytrid Epedemic: Short Version

Learn how the Chytrid fungus is killing amphibians in the Pacific Northwest, and around the world.

From Wildlife Extra:

Hope for frogs in a biodiversity hotspot: No chytrid fungus in West Africa

March 2013. Amphibians are one of the most threatened animal groups in the world; almost one third of all species are under acute threat. One of the main reasons for their decline is a chytrid fungus (Batrachochytrium dendrobatidis) with a nearly worldwide distribution. In a collaborative effort between Burke Museum researchers and other scientists from across the globe, close to 1,000 amphibians belonging to over 60 species were tested for the disease.

Widespread in southern, eastern, and central Africa

Chytridiomycosis, the disease caused by the fungus, is known to be highly lethal to frogs and is believed to be responsible for the worldwide amphibian decline. In infected individuals, the fungus attacks the skin and blocks respiration, eventually killing the animal. Chytrid is widespread in Africa, and every year new positive records are reported from countries in southern, eastern, and central Africa. The current study by an international team of biologists and herpetologists did not detect chytrid in West Africa despite extensive tests of 62 species from seven countries. This is especially remarkable because environmental factors clearly show that the fungus would find suitable conditions in West Africa.

Two co-authors of the study, Burke Museum Curator of Herpetology Dr. Adam Leaché and University of Washington biology graduate student Matt McElroy, travelled to Ghana in 2011 to collect specimens for the project. Of the nearly 1,000 amphibians analysed in the study, a significant portion were collected on this 17-day Burke expedition, representing more than 40 different species. All are at the Burke Museum and are available to the public for future research. McElroy conducted genetic tests on more than 100 individual frogs to detect the chytrid fungus, all of which were negative (no fungus detected).

One hypothesis is that the chytrid fungus originated in Africa and dispersed globally via the pet trade. This makes the study’s finding-that chytrid is not present in West Africa-all the more unusual and interesting.

‘Dahomey Gap‘

The researchers used both genetic and histological tests to analyse the samples collected from the field. The consistently negative (chytrid free) results they found stand in stark contrast to what models of environmental parameters might predict. One explanation for this incongruence, according to Johannes Penner, the lead author on the study, is the Dahomey Gap; an arid region in Togo and Benin that naturally divides the rain forests in West Africa from Central Africa and in turn acts as a natural barrier for the dispersal of the fungus.

“Chytrid is having negative impacts on amphibian communities on a global scale, and our study provides hope that at least one highly diverse region of Africa may remain unaffected by this pathogen,” Dr. Leaché said. “Fieldwork and research conducted by Burke graduate students and undergraduates was instrumental to this study. Their efforts made a significant contribution.”

No fungus in Madagascar

It now appears that West Africa is the last tropical region beside Madagascar where chytrid does not exist, potentially sparing West Africa from the great amphibian decline affecting the rest of the world. Unfortunately, according to many experts, destruction of natural habitats, which happen on a large scale in West Africa, can easily rival the devastation of even chytrid.

To prevent chytrid from spreading into West Africa via the trade of frogs for the food market, the researchers suggest various precautionary measures. For example, the transport of potential fungus infected materials between the regions should be controlled and materials prophylactically disinfected. In addition, an early warning system would be useful to detect the appearance of the fungus in Ghana, a potential entry point. These actions could eliminate a significant threat to the amphibians of West Africa, and be utilized by conservationists to help other amphibian populations across the globe.

The report was recently published in the science journal PLOS ONE.

Deadly frog fungus found in Southeast Asia’s amphibian trade: here.

FROGS THAT MAINTAIN high body temperatures are better protected against a deadly fungus, according to research sponsored by the Australian Geographic Society: here.

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Almost-extinct Tanzanian toads reintroduced to wilderness

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This video is called Kihansi Spray Toads Return to the Wild.

From Tanzania Daily News (Dar es Salaam):

Tanzania: Kihansi Toads Reintroduced in the Wilderness

By Abdulwakil Saiboko, 12 March 2013

Kilombero — TANZANIA has gone down in history as the world’s first country to successfully reintroduce into the wild amphibians that had been in danger of extinction.

This has been revealed during the release of the second batch of 1,500 Kihansi Spray Toads (KST) into their natural habitat at Kihansi gorge at the weekend. A health complication known as chytrid fungus led to massive deaths of the species in the early 2000s.

A researcher from the University of Utah in the US, Dr William Newmark, said shortly after the release that the occasion was the first in the world and that many countries will have to learn from Tanzania. “This is the first time in Africa as well as the world, where we have witnessed a successful reintroduction of amphibians into the wild. This is the result of careful experiments,” he said.

Dr Newmark, who is also a consultant with the World Bank, noted that local and international scientists working in the reintroduction process have agreed to release a significant number of toads every year. “We will learn as we go along. The first release came with challenges that we tried to address in this second round.

Likewise, the coming round will be improved further as we will be having new ideas to bank on,” he said. He added that plans were underway to reintroduce another 3,500 toads as soon as possible. The University of Dar es Salaam Head of Zoology and Wildlife Conservation, Dr Felister Urasa, said that the first batch of 2,000 toads was released into the wild on October 30, last year.

“Those introduced in the first batch are doing fine and this is due to the fact that researchers have made efforts to see into it that there is enough food at the gorge and that their habitat is free from diseases,” she said. She added that tireless efforts made by National Environment Management Council, Tanzania Wildlife Research Institute, University of Dar es Salaam, Sokoine University of Agriculture and World Bank have seen the toads going back home.

The Lower Kihansi Environmental Management Project Co-ordinator, Ms Amina Kibola noted that Tanzania Electric Supply Company (TANESCO) has also contributed greatly in the process. “Tanesco has put an artificial sprinkler in place, trained ten officials who work in ensuring that the spray system works properly.

Kihansi stands as a successful story of Tanesco’s environment management efforts,” she said. Ms Kibola noted that a lot of efforts have been made in educating villagers in the vicinity of the gorge in ensuring that they are not involved in activities that are detrimental to the welfare of the toads.

The Tanzania Wildlife Research Institute (TAWRI) Eastern and Southern Zonal Coordinator, Dr Denis Ikonda, noted that his institute would ensure the sustainability of the toads in the wild. “We have the role of ensuring that the toads are not getting extinct once again and this will be done by ensuring that all the detrimental elements are prevented,” he said.

Dr Ikonda, who led the reintroduction exercise, noted further that objectives will be achieved given a reputable background TAWRI has in dealing with cases of that nature. He pointed out the recent reintroduction of wild dogs into Serengeti National Park as vivid example.

Wild dogs disappeared from the Serengeti in the 1980′s. During the construction of Lower Kihansi Dam, the population of KST which are unique of Kihansi declined due to the reduction of the amount of wetland habitat receiving natural spray. The toads’ population was attacked by a fungal disease called chytridiomycosis that threatened to wipe out the rare species from the face of the world.

About 500 of the toads, scientifically known as Nectophrynoides Asperginis, were in the year 2000 taken to the United States, because they were in danger of extinction. At Bronx and Toledo Zoos in the US the toads are said to have multiplied to over 6,000. The scientists have noted that the successful study will see many more toads being flown back home from the US.

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Don’t let cars kill Canadian reptiles, amphibians, video

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The Sticky Tongue Project in Canada says about this video:

Roads and Migration Routes

Road mortality along migration routes can eliminate amphibian and reptile populations. Here’s a few things you can do to help in your own community.

Episode 9 of a year-long 24 episode education-outreach video series starring Whit Gibbons: Herpetologist, Author, that we produced in cooperation with The Amphibian and Reptile Conservancy.

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