Sunday, May 29, 2011

Modern EU Agriculture Jeopardises Biodiversity in New Member States

A new study from Romania highlights the importance of traditional agriculture in protecting amphibians.

Traditional agricultural practices can make a major contribution to preserving biodiversity in the EU’s new member states in Central and Eastern Europe. By contrast, the construction of roads and the intensification of agriculture currently encouraged by EU farming subsidies pose a threat to amphibians. The rich natural environment still extant in many accession countries is under threat, according to scientists writing in the journal Biological Conservation.

The researchers from Romania, Germany and the Netherlands investigated amphibians for their study in the Romanian province of Transylvania. They spent nine years studying the populations of various species of newts, frogs and toads in 54 ponds and related their performance to nearby land use.

All in all, the scientists found 10 amphibian species in the surveyed ponds, including EU-wide protected species like the Great Crested Newt and the Yellow Bellied Toad. Statistical evaluation revealed that roads had the biggest impact on their populations. Other factors like the size of ponds, building development, farmland, pasture, woodland and marshlands proved to be far less important. "Roads have a direct negative effect on many species of amphibians, which can get run over by cars. But roads also have an indirect impact, for example by the destruction and isolation of the critical habitats for amphibians such as breeding, summering and overwintering habitats" explained Dr Tibor Hartel from Babeş-Bolyai University, Cluj-Napoca (Romania).

The study area was the "Saxon area" of Southern Transylvania along the Târnava Mare basin in Romania. The agriculture is still largely traditional in this region, sometimes with little changes through the centuries. The landscape is dominated by pasture and deciduous forest, while the arable lands are small sized and scattered across the native grassland vegetation. Mankind’s negative impact on biological diversity is statistically still far lower in Eastern Europe than in the West - but this traditional cultural landscape and hence its unique biodiversity could soon disappear if agriculture were to be intensified. "We believe that the comparatively extensive agriculture in the study region with little machinery and hardly any chemicals provides conditions which are still suitable for many amphibian species," explains Dr Oliver Schweiger from UFZ.
The findings could have important consequences for protective measures for amphibians in regions of Central and Eastern Europe, where farming has remained largely traditional. Preserving traditional, extensive land management could be the key factor in protecting these species. However, that could be a tough challenge, for many regions, joining the EU will lead to more intensive land use and infrastructure expansion. And that in turn will result in the fragmentation of the landscape and the general deterioration of the remaining habitats. Researchers are now calling for a balance to be struck between the legitimate desire for improved infrastructure and higher agricultural yields on the one hand and the beneficial effects of extensive land use on the other. In their view, this challenge should be regarded as an opportunity for Eastern Europe not to repeat the mistakes made in the West.

Photos: The common toad, Bufo bufo. And an agricultural pond Photo credits: Tibor Hartel/Babes-Bolyai-Universität Cluj-Napoca.

Saturday, May 28, 2011

Regulating Snake Charmers & Their Snakes

The following story by  Stephanie Nolen of The Globe and Mail was published on May27, 2011. There is at one interesting comment associated with this story.And, it makes the point that cobras are often urban snakes, living in close proximity to humans and feeding on rats and other snakes. See the Urban Snakes post from a few days ago.

Pali Nath believes his cobras are 1,000 years old. This may be a slight overstatement, but it speaks to his sense that his trade – snake charmer – is an ancient, integral part of Indian culture. He plies it at weddings and other auspicious occasions, and sometimes on the pavement at busy crossroads in Delhi.

When he squats on his haunches and begins to plays his flute, then lifts the lid off a wicker basket of coiled snakes, the music and the swaying of the serpents has an other-worldly quality. He draws a crowd that, for a few minutes, falls still in this cacophonous city.

This is also, however, a modernizing city, and ancient though the practice of snake charming may be, it must keep up with the times.

Thus the municipal government of Delhi recently summoned Mr. Nath and a number of his confederates to have their snakes microchipped.

Yes. Microchipped.

Back in 2003, Delhi’s wildlife department ordered all city residents with wild animals to register their beasts. Dancing bears, auspicious-occasion elephants, festive camels, performing monkeys, parrots who tell fortunes and rats that predict the future – this concrete jungle is rich in fauna.

The city hoped that by declaring an amnesty to register wild animals in the city, it would help to stop the wildlife trade.

Mr. Nath read about the amnesty in the newspaper, and signed up. It took the city eight years to work its way around to the snake charmers, but a few weeks ago, he got the call to bring in his snakes.

In a bare city office, he met Nitin Sawant, a herpetologist who is the director of the Goa office of the World Wildlife Fund India. The city brought Mr. Sawant north because he is one of the few people in the country with an expertise in PIT-tagging (that’s Passive Integrated Transponder, for the uninitiated) snakes, a skill he picked up PIT-tagging pit vipers for his doctoral research in zoology.

Mr. Sawant took each snake in turn, popped its head and neck into a clear plastic tube to keep it still, and used a needle to insert the tag – smaller than a grain of rice – into the snake’s skin, below the top layer that is shed. Each chip carries a unique identity number.

Then Mr. Nath was given a stamped, laminated certificate that records the species, length, weight and unusual identifying characteristics of his six snakes. And that changed his life.

“Before I was being harassed all the time by inspectors, but now when they stop me I show them this certificate,” he said. Wildlife officers can use a handheld scanner to read the chip and confirm the snakes he is carrying are the ones he registered.

Snake charming, like any activity with a wild animal, was outlawed in the mid-1990s. Inspectors patrol for violators, seeking in theory to confiscate animals or, more typically, to demand bribes from the snake charmers to leave them alone.

Now, Mr. Nath said, his fellow charmers are left living in fear of inspectors, keeping to the shadows, while he can operate freely. He was reluctant to be too specific about what he earns, but he seemed prosperous enough, wearing crisp, bright-orange robes stretched over a firm belly.

Only 10 snake charmers, with a total of 43 snakes, came forward for microchipping, according to a wildlife official who declined to be quoted by name; he estimated there are at least 50 more snake charmers at work in Delhi. The initiative has been “very cheap,” he said, at a cost of about 55,000 rupees, or $1,200.

Mr. Nath insisted none of his snakes came through illegal wildlife trading. Rather, he said, they were spotted in buildings around the city and he was called to remove them. “I have caught snakes in the Kuwaiti embassy, in the home of the minister of external affairs, in the railway museum,” he said.

Once he catches them, he defangs the snakes, using a method he learned from his father that he declined to detail. Because they are defanged, his snakes cannot hunt, and he feeds them deboned chicken and fish, plus yoghurt in summer. He carries them around the city in a basket tied shut with string. And he loves them dearly. “In the winter, they sleep with me under the quilt, not my kids,” he said in Hindi.

However, Mr. Sawant, a man with a warm-blooded passion for reptiles, was appalled at the state of the snakes he tagged.

“The way they are catching and treating the snakes is torture, and they were sluggish, they are not in good health,” he said. “I told all of the [snake charmers] that they should leave this profession: ‘If somebody puts your child in a bucket and makes them dance, you will not be happy.’ They said, ‘But, sir, we don’t have any livelihood.’ ”

Mr. Nath said his snakes will live at least several hundred more years (unless bitten by a mongoose) and thus he will never need more. If he did, he said, he would keep a few eggs when his current snakes mate, but never trap a wild snake.

The herpetologist was skeptical. “Obviously these snakes are in bad health and they will die and they will go for new snakes.”

The microchipping may help, he said, but it relies on a fairly high level of efficiency by wildlife inspectors. The king cobra and python species favoured by snake charmers are not yet endangered but are threatened, Mr. Sawant said.

Mr. Nath counters that he has a religious and near-mystical relationship with his snakes, that he and they are bonded through his music. (This idea is somewhat undermined by the fact that he has to jab and poke the snakes, which respond by striking furiously at his hands, in order to get them to “dance.”)

“It’s a talent, a work of art, and it’s legalized with this certificate,” he said.

Friday, May 27, 2011

Suction-Feeding Ichthyosaurs

Photograph and drawing of skull of YGMIR SPCV03107. (A) in left lateral view. Note the greatly abbreviated rostrum, the complete lack of teeth, the large foramina in the maxillary and lacrimal bones, and the dorsally convex coronoid region of the dentary (arrow). (B) in dorsal view. Note the nasals extending to the tip of the rostrum. Abbreviations: a, angular; ar, articular; d, dentary; en, external nares; f, frontal; if, internasal foramen; j, jugal; l, lacrimal; mx, maxilla; pa, parietal; pf, postfrontal; pm, premaxilla; po, postorbital; prf, prefrontal; qj, quadratojugal; sa, surangular; sq, squamosal; st, supratemporal; uto, upper temporal opening.
Ichthyosaurs were important in Mesozoic marine ecosystems and lived from the Early Triassic to the early Late Cretaceous. Despite a great diversity in body shapes and feeding adaptations, all share greatly enlarged eyes, an elongated rostrum with numerous conical teeth, and a streamlined body.

Now, P. Martin Sander and colleagues have examined new material from China and taken a second look at Shastasaurus pacificus, and discovered the classical large-bodied Late Triassic ichthyosaur genus Shastasaurus to differ greatly from the standard ichthyosaurian body plan, indicating much greater morphological diversity and range of feeding adaptations in ichthyosaurs than previously recognized. Phylogenetic analysis indicates a monophyletic clade consisting of the giant Shonisaurus sikanniensis, Guanlingsaurus liangae, and Shastasaurus pacificus to which the genus name Shastasaurus is applied. The Shastasaurus liangae is from the Late Triassic (Carnian) Xiaowa Formation of Guizhou Province, southwestern China. The species combines a diminutive head with an entirely toothless and greatly reduced snout. The species also has by far the highest vertebral count among ichthyosaurs (86 presacral vertebrae and more than 110 caudal vertebrae), a count that is also very high for tetrapods in general. A reduced toothless snout and a diminutive head is also present in the giant S. sikanniensis and presumably in S. pacificus.They concluded that Shastasaurus is a specialized suction feeder, that fed on unshelled cephalopods and fish, suggesting a unique but widespread Late Triassic diversification of toothless, suction-feeding ichthyosaurs. Suction feeding has not been hypothesized for any of the other diverse marine reptiles of the Mesozoic before, but in Shastasaurus the behavior may be linked to the Late Triassic minimum in atmospheric oxygen.

Sander PM, Chen X, Cheng L, Wang X (2011) Short-Snouted Toothless Ichthyosaur from China Suggests Late Triassic Diversification of Suction Feeding Ichthyosaurs. PLoS ONE 6(5): e19480. doi:10.1371/journal.pone.0019480

Wednesday, May 25, 2011

A New Fanged Frog From Sumatra

A species of Limnonectes and its odontoid 
proceeeses. Photo JCM.
The frog genus Limnonectes Fitzinger holds 55 species with odontoid processes (tooth-like structures), and are therefore called “fanged frogs.” Fanged frogs have large males and male parental care. They are found throughout east and Southeast Asia, and are usually associated with forest stream habitats, and two or members of the genus may live together. Limnonectes kuhlii Tschudi was long believed to be a widespread species, but recent molecular work revealed considerable diversity within the species complex.  L. kuhlii, historically recognized as a single species, is a complex of more than 22 well-supported species 16 of which are currently subsumed under the nominal L. kuhlii. Tschudi (1838) designated the island of Java as the type locality for L. kuhlii. Thus, all individuals from Java to retain the name L. kuhlii. A series of frogs collected from three stream systems in West Sumatra and identified as Limnonectes kuhlii were found to be a distinct, undescribed species. Now, Mcloed et al. (2011) have described these specimens as a new species, Limnonectes sisikdagu, which has a spine covered mental plate.

Mcleod, D. S. et al. 2011. “Same-same, but different”: an unusual new species of the Limnonectes kuhlii Complex from West Sumatra (Anura: Dicroglossidae). Zootaxa 2883:53-64.

Tuesday, May 24, 2011

Urban Indian Snakes

Snakes adapt to a variety of urban environments, feeding on human commensals and using the artificial burrows and crevices created by construction, and in the greenspaces created for urban dwellers. The following story is being carried by The New Indian Express.
MYSORE: More than 25 different species of snakes have been spotted in Mysore city. Snakes are frequently found on the streets and other public localities. The population of cobras is rising in the city.This has kept Snake Sham, Pradeep and other snake catchers busy as they have been getting many calls to catch snakes in and around the city.The rescue calls often come from new layouts like Dattagalli, Rajeev Nagar, Revneu layout, Srirampura, J P Nagar, Ramakrishna Nagar, Hebbal, Saradar Valabai Patel Nagar and other areas in the city. The Infosys campus is one such area where Snake Sham alone has caught 485 snakes.Though, there are about 270 species of snakes in India, there are more than 25 species in the city including venomous and nonvenomous species like the Trinket, Sand boa, Tree snake, Green Vine, Racer, Wolf, Buff Striped, Keel Back and Rat snakes.There are also venomous snakes like the Cobra, Viper, Saw Scaled Viper and Krait snake. These snakes are sizeable in number in lush green and largely vegetated areas.According to Snake Sham, who has caught more than 24,015 snakes since 1997, more than 60 per cent of the snakes caught are Cobras.He said that greenery, availability of food like rats and frogs, water and the temperature are the reasons for the vast snake population in city.Sham says that there is only a remote chance for the decline in snake population in the city as one snake alone can lay as many as 20 eggs at once and a Viper gives birth to over 50 young ones.The movement of snakes in the city is recorded to be the highest during the summer months and these professional snake catchers get numerous rescue calls at this time of the year. Six pythons were caught around the city and have been presented to the Mysore Zoo. Sham feels that the residents should be careful at night, keep their lights switched on, have a mesh for windows and doors and avoid dumping waste in car sheds. The catchers feel that the belief to not kill a Cobra is a major reason for the increase in its population.

Monday, May 23, 2011

Oil Palms & Species Diversity

Oil palm plantations are having a 
devastating effect on biodiversity. 
Photo Credit:Matthew Struebig.
The following press release discusses the impact of bat diversity in oil palm plantations, while some forest frogs can survive in these human made ecosystems, they too suffer a loss of species.

Forest fragmentation driven by demand for palm oil is having a catastrophic effect on multiple levels of biodiversity, scientists from Queen Mary, University of London have discovered.

The researchers are worried that unless steps are taken to safeguard and manage the remaining forest, then certain species will struggle to survive.

The study, which focused on bats as an indicator of environmental change, was published in one of the leading scientific journals, Ecology Letters.
The team conducted bat surveys in pristine forest and also in forest patches of varying size in central Peninsular Malaysia. They recorded the numbers of different species present and also assessed the level of genetic diversity within populations of some species.

Lead author Matthew Struebig, jointly based at Queen Mary University of London and the University of Kent, said: “We found that smaller forest areas support fewer species, and that those species that remain face an eventual decline, potentially leading to local extinction in the long-term.”

When the team compared the number of species present to genetic diversity within populations they found that fragmentation appeared to have an even greater impact on genetic loss, which might also be important for long-term population viability.

“We found that in order to retain the numbers of bat species seen in pristine forest, forest patches had to be larger than 650 hectares, however to retain comparable levels of genetic diversity, areas needed to be greater than 10,000 hectares,” he said.

Co-author Stephen Rossiter, also at Queen Mary, emphasised that the findings could have important implications for forest management in the face of the ever-growing demand for oil palm plantations.

He said: “We found that while more species existed in larger forest patches, even small fragments contributed to overall diversity. Therefore, conservation managers should aim to protect existing small fragments, while seeking to join up small forest areas to maximise diversity.”

Sunday, May 22, 2011

Amphibians Prey for Epomis Beetles

New findings from Tel-Aviv University show that predator-prey interactions between ground beetles of the genus Epomis and amphibians are much more complex than expected. The study was published in the open access journal Zoo Keys.

"Amphibians are typical insect predators and their diet may include adult beetles, ground beetles in particular. The recently filmed successful attacks of the beetles on toads and frogs brought new insights on the amphibian-insect interactions, and documented the uncommon phenomenon of invertebrates preying on vertebrate animals," said the senior author Gil Wizen.

This image shows the predation of 
amphibians by an adult Epomis beetle. 
Photo credit: Gil Wisen
Previous research has shown that Epomis larvae feed exclusively on amphibians and that this food source is essential for completion of their life cycle, while the diet of the adult beetles consists of terrestrial invertebrates as well as dead vertebrates. Wizen and Gasith's current study shows that adult Epomis beetles can prey upon live amphibians, in addition to their regular diet.

According to the study, the genus Epomis is represented in Israel by two species: E. dejeani and E. circumscriptus. In the central coastal plain these species have similar distribution but do not occur in the same sites. The researchers recorded Epomis sharing shelter with amphibians during the day, but preying on them during the night. In the laboratory, predation behaviour of the adult beetles on five amphibian species was observed: the Green Toad (Bufo viridis), the Savignyi's Frog (Hyla savignyi), the Levant Green Frog (Rana bedriagae), the Banded Newt (Triturus vittatus), and the Fire Salamander (Salamandra salamandra infraimmaculata). These observations showed that the diet of the two Epomis species overlaps only partially, with only one of the species (E. dejeani) preying on the Banded Newt.

The results of this study serve as additional evidence that Epomis beetles, both larvae and adults, are specialized predators of amphibians. Moreover, these beetles prey upon several amphibian species.

To watch a video of one of these carib beetles preying on a green toad. Click Here

Saturday, May 21, 2011

Two New Uropeltids

The following article is from the Sunday Times, Colombo, Sri Lanka. The article discussed is available on-line. Just follow the link below.

As the world marks International Day of Biological Diversity today --May 22, two new endemic snakes have been added to Sri Lanka’s unique biodiversity list.

Both snakes are non-venomous primitive burrowing snakes that live underground in loose soil and are commonly referred to as Shield-tailed snakes because of the keratinous shield at the end of their tail which helps them to burrow in loose soil.

The new snakes are classified as Rhinophis lineatus and Rhinophis zigzag. Dr. Maduwage first spotted the differences in these Uropetid or shield-tail snakes from similar breeds during a stint at the world Heritage Trust (WHT) a few years ago as a researcher.

Having carefully examined the specimens, he discovered three specimens from one species and two from another. Dr. Maduwage then compared scale characteristics with published evidence of other snakes of this genus and found that the two snakes did not match any other shield-tail snake.

Dr. Kalana Maduwage – a medical officer who has been studying snakes for over 10 years specially the Hump-nosed pit viper. In addition he also discovered 10 varieties of fish and discovered another species of Sri Lankan snake previously.

The numerous distinguished scale characters, the presence of multiple, narrow longitudinal stripes around and along most of the body helped distinguished Rhinophis lineatus from all other members of this genus.

Dr. Maduwage said the Rhinophis zigzag also had a distinctive and consistent colour pattern of a dark meandering/zigzag stripe which was absent in all other species of the group.

After initial observations in 2007, Dr.Maduwage contacted Dr David Gower --a leading expert on Shield-tail snakes. The experts then worked together on a research paper, which were published last week.

These unique variety of snakes are found only in Western Ghats of India & in Sri Lanka –both of which are hotspots in the world of biodiversity.

Prior to the latest discovery, only 13 species of the Uropetid snakes were known to exist. The 12 Sri Lankan species are endemic to the country. This means they are found only here.

In 2009, another species of the shield-tail snake was discovered at Rakwana by herpetologist Mendis Wickremasinghe and was categorized Rhinophis erangaviraji. The two new species were discovered at a single locality.

The Rhinophis lineatus is found only at Harasbedda near Ragala while Rhinophis zigzag was discovered at “Bibilegema Rd.” near Passara, in the Uva Province.

Gower D. J. and K. Maduwage. 2011. Two new species of Rhinophis Hemprich (Serpentes: Uropeltidae) from Sri Lanka. Zootaxa 2881:51-68.

Xilousuchus sapingensis - An Early Archosaur

A reconstruction of X. sapingensis, based on the fossil. Sterling Nesbitt
A fossil unearthed in China in the 1970s of a creature that died about 247 million years ago, originally thought to be a distant relative of both birds and crocodiles, turns out to have come from the crocodile family tree after it had already split from the bird family tree, according to research led by a University of Washington paleontologist.

The only known specimen of Xilousuchus sapingensis has been reexamined and is now classified as an archosaur. Archosaurs, characterized by skulls with long, narrow snouts and teeth set in sockets, include dinosaurs as well as crocodiles and birds.

The new examination dates the X. sapingensis specimen to the early Triassic period, 247 million to 252 million years ago, said Sterling Nesbitt, a UW postdoctoral researcher in biology. That means the creature lived just a short geological time after the largest mass extinction in Earth’s history, 252 million years ago at the end of the Permian period, when as much as 95 percent of marine life and 70 percent of land creatures perished. The evidence, he said, places X. sapingensis on the crocodile side of the archosaur family tree.

“Archosaurs might have survived the extinction or they might have been a product of the recovery from the extinction,” Nesbitt said.

The research is published May 17 online in Earth and Environmental Science Transactions of the Royal Society of Edinburgh, a journal of Cambridge University in the United Kingdom.

Co-authors are Jun Liu of the American Museum of Natural History in New York and Chun Li of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China. Nesbitt did most of his work on the project while a postdoctoral researcher at the University of Texas at Austin.

The X. sapingensis specimen – a skull and 10 vertebrae – was found in the Heshanggou Formation in northern China, an area with deposits that date from the early and mid-Triassic period, from 252 million to 230 million years ago, and further back, before the mass extinction.

The fossil was originally classified as an archosauriform, a “cousin” of archosaurs, rather than a true archosaur, but that was before the discovery of more complete early archosaur specimens from other parts of the Triassic period. The researchers examined bones from the specimen in detail, comparing them to those from the closest relatives of archosaurs, and discovered that X. sapingensis differed from virtually every archosauriform.

Among their findings was that bones at the tip of the jaw that bear the teeth likely were not downturned as much as originally thought when the specimen was first described in the 1980s. They also found that neural spines of the neck formed the forward part of a sail similar to that found on another ancient archosaur called Arizonasaurus, a very close relative of Xilousuchus found in Arizona.

The family trees of birds and crocodiles meet somewhere in the early Triassic and archosauriforms are the closest cousin to those archosaurs, Nesbitt said. But the new research places X. sapingensis firmly within the archosaur family tree, providing evidence that the early members of the crocodile and bird family trees evolved earlier than previously thought.

“This animal is closer to a crocodile, but it’s not a crocodile. If you saw it today you wouldn’t think it was a crocodile, especially not with a sail on its back,” he said.

The research was funded by the National Science Foundation, the Society of Vertebrate Paleontology, the American Museum of Natural History and the Chinese Academy of Sciences.

“We’re marching closer and closer to the Permian-Triassic boundary with the origin of archosaurs,” Nesbitt said. “And today the archosaurs are still the dominant land vertebrate, when you look at the diversity of birds.”

A "Missing Link" Fossil Between Laceretids and Amphisbaenians

The nearly complete fossil of Cryptolacerta 
hassiaca (Photo Credit:University of Toronto)

Until a recent discovery, theories about the origins and evolutionary relationships of snakes barely had a leg to stand on.

Genetic studies suggest that snakes are related to monitor lizards and iguanas, while their anatomy points to amphisbaenians ("worm lizards"), a group of burrowing lizards with snake-like bodies. The debate has been unresolved--until now. The recent discovery by researchers from the University of Toronto Mississauga and the Museum für Naturkunde Berlin, Germany of a tiny, 47 million-year-old fossil of a lizard called Cryptolacerta hassiaca provides the first anatomical evidence that the body shapes of snakes and limbless lizards evolved independently.

"This fossil refutes the theory that snakes and other burrowing reptiles share a common ancestry and reveals that their body shapes evolved independently," says lead author Professor Johannes Müller of Humboldt-Universität, Berlin.

The fossil reveals that amphisbaenians are not closely related to snakes, but instead are related to lacertids, a group of limbed lizards from Europe, Africa and Asia. "This is the sort of study that shows the unique contributions of fossils in understanding evolutionary relationships," says Professor Robert Reisz from the University of Toronto Mississauga, the senior author of the study. "It is particularly exciting to see that tiny fossil skeletons can answer some really important questions in vertebrate evolution".

The German research team, led by Müller and American graduate student Christy Hipsley, used X-ray computed tomography to reveal the detailed anatomy of the lizard's skull and combined the anatomy of Cryptolacerta and other lizards with DNA from living lizards and snakes to analyze relationships. Their results showed that Cryptolacerta shared a thickened, reinforced skull with worm lizards and that both were most closely related to lacertids, while snakes were related to monitor lizards like the living Komodo dragons.

Even though snakes and amphisbaeans separately evolved their elongate, limbless bodies, the discovery of Cryptolacerta reveals the early stages in the evolution of burrowing in lizards. By comparing Cryptolactera to living lizards with known lifestyles, co-author and U of T Mississauga paleontologist Jason Head determined that the animal likely inhabited leaf-litter environments and was an opportunistic burrower.

"Cryptolacerta shows us the early ecology of one of the most unique and specialized lizard groups, and also reveals the sequence of anatomical adaptations leading to amphisbaenians and their burrowing lifestyle," says Head. "Based on this discovery, it appears worm-lizards evolved head first."

Johannes Müller, Christy A. Hipsley, Jason J. Head, Nikolay Kardjilov, André Hilger, Michael Wuttke, Robert R. Reisz. Eocene lizard from Germany reveals amphisbaenian origins. Nature, 2011; 473 (7347): 364 DOI: 

Monday, May 16, 2011

Foothill yellow-legged frog provides insight on river management

The Yellow-legged Frog, Rana boylii. Photo Credit R. Peek.
DAVIS, Calif.—River flow fluctuations downstream of dams are often out of sync with natural flow patterns and can have significant negative effects on aquatic species, such as native frogs, according to a team of scientists from the USDA Forest Service's Pacific Southwest Research Station, the University of California, Davis and the University of California, Berkeley.

The team examined how altered water flows caused by hydroelectric dams impact the life cycle of the foothill yellow-legged frog (Rana boylii). The frog, which lives in foothill regions from southern California to southern Oregon, completes its life cycle exclusively in riverine environments. The species is well-adapted to predictable flow patterns that are high during the spring run-off period and low during the summer. Changes to these patterns affect the survival of eggs and tadpoles and consequently are likely to be a primary factor in limiting populations of this declining species, scientists say.

Findings from three recent research projects are published in Copeia, River Research and Applications, and Conservation Genetics. These studies revealed that R. boylii tadpoles are not strong swimmers and do not survive the high flow events that can occur during the summer months in many dammed rivers, leading to local population declines. The team tested a habitat modeling tool that is commonly used for fish, with eggs and tadpole data from R. boylii, and found that it could provide reliable predictions of habitat changes under different flow scenarios. Genetic research conducted by the team identified several isolated and unique populations at the extremes of the geographic range and also demonstrated the important role of river basins in defining relationships among populations. The combined results of this work can guide conservation planning for the species.

Managing water discharge from hydroelectric dams to mirror the environment's natural flow is ideal, but this approach may not meet the needs of human consumption and energy demands.

"To conserve riverine species, one solution may be to restore some of the key characteristics of natural flow patterns, especially the timing of high and low flow periods," says Amy Lind, wildlife biologist at the Pacific Southwest Research Station in Davis, Calif., and co-author of three recent papers on R. boylii ecology and genetics.

Kupferberg, S.; Lind, A.; Thill, V.; Yarnell, S. 2011. Water velocity tolerance in tadpoles of the foothill yellow-legged frog (Rana boylii): Swimming performance, growth, and survival. Copeia 2011(1):141-152.

How Many Species of Snakes Are There?

The number of species of snakes described each year since 1758.  The text in black notes the authors who contributed a significant number of species in various years where the number of species that were described spiked.
Ask this question on Goggle and most of the top dozen websites provide answers that range from "more than 2000" to "2950." The exception is the Reptile Database website that reports 3149 species as of February, 2008, and 3,315 species as of January 2011. Since this list undoubtedly receives the most detailed attention and updating by herpetologists it is likely to be the most authoritative answer for the moment. But really - how many species of snakes are there?

Using the Reptile Database I graphed the number of currently recognized snake species described each year from 1758 to 2010, divide the 3315 species by the number of months and you get about 1.09 snake species have been described each month for the past 253 years. However, there is reason to believe that there are many species that remain to be described.

Passo and Lynch (2010) revised the cryptozoic snakes in the genus Atractus from the middle and upper Magdalena drainage of Colombia. Prior to the publication of this paper five species were known from the region, they added three new ones, an increase of 60%. Of the 135 currently recognized species of Atractus, 42 (31%) species have been described since 2000. The blind snakes of the genus Typhlops also currently number 135 species, of these 14.8% have been described since 2000. Another species rich genus is Oligodon, the Asian Kukri Snakes. Currently 68 species are recognized, six (8.8%) have been described since 2000. Thus, many snake species clearly remain to be described.

The reasons for this situation appear to be the tendencies of Albert Günther and George Boulenger, both world renowned 19th century herpetologists, to lump species together. They decided that many of the species described between 1758 and 1860 were in fact species that had been named more than once. As they tried to organize the reptiles in the collection at the British Museum of Natural History they described some new species, but they also synonymized many species previously described under names they thought represented the earliest description of a particular species. This could have been a highly useful service to science, but unfortunately they did this many times without actually examining type specimens.

However, other factors are also involved. Species concepts have also changed. Concepts based strictly on scale counts and other morphology have been replaced with concepts based on isolation of gene pools and populations that are on their own evolutionary pathway.

As I worked my way through the homalopsid specimens in the 1990’s, it became clear that specimens labeled Enhydris jagorii represented at least three different species. Most of the specimens labeled jagorii had a mid-ventral stripe, a relatively high ventral count, there was another species with an exceptionally low ventral count, and yet a third species with an intermediate ventral count. Each had a distinctive pattern, but similar dorsal scale row counts, and head scale arrangements. Just laying one of each next to each other, it was clear they were distinct. Thus, three species were considered to be one. This situation is not uncommon, thus it would appear that the actually number of snake species could be conservatively estimated to increase by 1.5 to 2 times.

Murphy, J. C. 2007. Homalopsid Snakes, Evolution in the Mud. Krieger Publishing, Malabar, Florida.

Passos P. and J. D. Lynch. 2010. Revision of Atractus (Serpentes: Dipsadidae) from Middle and Upper Magdalena Drainage of Colombia. Herpetological Monographs, 24:149-173.

Blood & Guts, Information from Dead Snakes: Roger Repp's Suizo Report

Howdy Herpers,
If you're squeamish about dissection, delete this email now. This may be a little hard core for some of you, but I expect others could benefit from these images. I scanned them for that very reason. They are, of course, up for grabs, citations are with the text for each pic.

Pic 1: I encountered a DOR pregnant atrox on 12 August 2002. Thanks to the scalpel of Schuett, it didn't go to waste. This image shows 8 nearly fully formed neonates, still inside of mamma. Courtesy Schuett/Repp 
Pic 2: Neonates removed and stacked next to mamma. Courtesy Schuett/Repp

Pic 3: Young female neonate. Courtesy Schuett/Repp
The next three images are from an old Herp Review Pub. I do believe this is the first time my name appeared as an author in peer review land. And there wasn't even a parade to honor the event! 

Pic 4: Neonate Crotalus cerberus, as found near Flagstaff on 30 September 2000. Note the food bolus. There were some attempts to palpate the food bolus out of the hapless young cerb--to no avail. No doubt as a result of our attention to the matter, the snake died. While none of us were proud of that, we made the most of it. Courtesy Schuett/Nowak/Repp

Pic 5: The prey item proved to be what I THINK is called a Southwestern Fence Lizard, Sceloporus cowlesi. I believe they were called Eastern Fence Lizards at the time-- but by now, they may be something else. Who cares? The bottom line is that the prey item was heftier in mass than the snake itself. To use a line from Harry Greene--that is the equivalent of me eating a 250 pound big mac with no hands!

Pic 6: Prey item removed, and lined up in exact position as removed. Note that the head is already partially digested. Courtesy Schuett/Nowak/Repp

Ok, we're done with the likes of that. Our next report will go back to looking at herps from the outside again.
Best-est, roger

Sunday, May 15, 2011

Caiman Farms & Salmonella

The Wildlife Conservation Society and other
organizations released a new study recommending
 a disease screening program for farm-raised
caiman (including broad-snouted caiman) in
 ranching facilities in Argentina to ensure the
safety of people and wildlife alike. (Photo
Credit: Julie Larsen Maher/Wildlife
Conservation Society)
The Wildlife Conservation Society and other organizations released a new study recommending a disease screening program for farm-raised caiman in ranching facilities in Argentina to ensure the safety of people and wildlife alike.

The recommendations focus on two crocodilian species, the yacare caiman and broad-snouted caiman, both of which are reared in caiman ranches for sustainable harvest. The research team sought to assess the presence of potentially harmful bacteria in captive-raised caiman at a typical ranching facility in Argentina's Chaco region, where several facilities are currently in operation.

Crocodilian ranching programs are based on wild-harvested eggs and the release of excess hatchlings into the wild.

The study appears in the current edition of The Journal of Wildlife Diseases. The authors include: Marcela Uhart and Hebe Ferreyra of the Wildlife Conservation Society; Rosana Mattiello of the Universidad Nacional de Buenos Aires; María Inés Caffer and Raquel Terragno of the Instituto Nacional de Enfermedades Infecciosas, Administración Nacional de Laboratorios e Institutos de Salud; Adrianna Schettino of the Universidad Nacional del Centro de la Provincia de Buenos Aires; and Walter Prado of the Refugio de Vida Silvestre El Cachapé and the Fundación Vida Silvestre Argentina.

Between 2001 and 2005, the research team collected samples from more than 100 captive caiman at a ranching facility in the Argentinian Chaco region for the purpose of testing for Salmonella, a common bacteria in reptiles that can be harmful and occasionally deadly in animals and humans. During the survey, researchers found two species of Salmonella, both of which are known to cause disease in humans. Further, in one of the survey years (2002) Salmonella were present in 77 percent of samples collected, suggesting this was not an isolated finding. Since some of the hatchlings are returned to the wild, the chances of releasing infected caiman shedding this bacteria can be high.

"An accidental introduction of Salmonella or other pathogens into the environment during the release of captive-raised caimans could pose a health threat to wild caiman populations and other susceptible wildlife species, including some birds and mammals," said Dr. Marcela Uhart of WCS's Global Health Program and lead author on the study. "Preventive measures to detect the presence of harmful pathogens in caiman ranching facilities can help reduce potential health risks to humans as well as protect wild animal populations."

Caiman ranching facilities in Argentina currently raise more than 100,000 individual reptiles every year, all of which derive from eggs collected in the wild. Approximately 10 percent of all caimans raised in the facilities are returned to the wild; the rest are used for the commercial production of caiman hides for leather products and meat for local consumption. At present, there is no standardized health surveillance system for Argentina's ranching operations.

"Caimans almost became extinct in the late 1960s as a result of over-hunting for their hides," said Dr. Robert A. Cook, Executive Vice President and General Director of WCS's Living Institutions. "Today, the International Union for Conservation of Nature (IUCN) supports caiman ranches as a tool for crocodilian conservation. A health monitoring system would help ensure the sustainability of both reintroduction and commercial aspects of caiman ranching as well as the safety of products for human usage."

Dr. Uhart added: "We owe a debt of gratitude to both the owners of El Cachape ranch and Fundación Vida Silvestre Argentina for initiating the health assessment. The study highlights the potential for conservation-economic partnerships on private lands as well as the way responsible caiman ranching should be done."

Squamate Diversity - Five New Lizards

The blind snake lizard Dibamus dalaiensis 
Thy et al. 2011. Photo credit Neang Thy
The continuing discovery of new species of terrestrial vertebrates is a reminder that the diversity of life is much greater than was thought even 25 years ago. In the last few week five lizards (3 geckos, 1 skink, and 1 blind snake lizard) have been described from Venezuela, Madagascar, Indonesia, and Cambodia.

The blind snake lizard Dibamus dalaiensis ( family Dibamidae) was described from the Phnom Samkos Wildlife Sanctuary in the Cardamom Mountains of Cambodia by  Neang Thy and colleagues. It is significant because it represents a new family, genus and species record for Cambodia and it raise the number of species in the family Diabamus to 23, eight of these species (34%) have been described in the 21st century.

Marcelo Sturaro and Teresa Avila-Pires described two new species of dwarf day geckos of the genus Gonotodes (family Spaheordactylidae); one from eastern Amazonia, in the states of Pará and Amapá in Brazil (Gonatodes nascimentoi), and another from central Colombia, east of the Andes (Gonatodes riveroi), both are species of the Gonatodes concinnatus complex.The describtion of these geckos raise the number of species in the genus Gonatodes to 26, nine (33%) of which have been described in the 21st century.

Skinks make up the largest family of lizards, with more than 1450 known species. Aurelien Miralles and colleagues have described Madascincus arenicola, a new skink from the sand dunes of northern Madagascar. But, also of interest their molecular analysis found two related species (M. polleni and M. intermedius) genetically distinct, but morphologically indistinguishable. Madascincus now contains 11 species, 2 of which were described in the 21st century.

Djoko Iskandar and colleagues have described Cyrtodactylus batik a new species collected from Mount Tompotika, in the Balantak Mountains of Central Sulawesi, Indonesia. This large Cyrtodactylus (up to 115 mm in body length), forms a lineage with C. wallacei and C. jellesmae that appears to be endemic to Sulawesi. This raises the number of Cyrtodactylus geckos to 139, 59 (42%) of which have been described in the 21st century.

The message here - squamates are much more diverse than previously thought.

Iskandar, D. T., A. Rachmansah and Umilaela. 2011. A new bent-toed gecko of the genus Cyrtodactylus Gray, 1827 (Reptilia, Gekkonidae) from Mount Tompotika, eastern peninsula of Sulawesi, Indonesia. Zootaxa 2838:65-78.

Miralles, A.,  Kohler, J., Glaw, F., and M Vences. 2011. A molecular phylogeny of the “Madascincus polleni species complex”, with description of a new species of scincid lizard from the coastal dune area of northern Madagascar. Zootaxa 2876:1-16.

Thy, N., Holden, J, Eastoe, T., Rathea Seng, Saveng Ith, and Grismer, L.L. 2011. A new species of Dibamus (Squamata: Dibamidae) from Phnom Samkos Wildlife Sanctuary, southwestern Cardamom Mountains, Cambodia. Zootaxa 2828:58-68.

Sturaro, M. J. and T. C. S. Avila-Pires. 2011. Taxonomic revision of the geckos of the Gonatodes concinnatus complex (Squamata: Sphaerodactylidae), with description of two new species. Zootaxa 2869:1-36.

Saturday, May 14, 2011

Reptiles, Mammals, and the Triassic Climate

The skull of the procolophonid Hypsognathus 
was found in Fundy basin, Nova Scotia, which 
was hotter and drier when it was part of 
angaea. Mammals, needing more water, chose 
to live elsewhere. Photo Credit: Jessica 
Whiteside, Brown University.
More than 200 million years ago, mammals and reptiles lived in their own separate worlds on the supercontinent Pangaea, despite little geographical incentive to do so. Mammals lived in areas of twice-yearly seasonal rainfall; reptiles stayed in areas where rains came just once a year. Mammals lose more water when they excrete, and thus need water-rich environments to survive. Results are published in the Proceedings of the National Academy of Sciences.

PROVIDENCE, R.I. [Brown University] — Aggregating nearly the entire landmass of Earth, Pangaea was a continent the likes our planet has not seen for the last 200 million years. Its size meant there was a lot of space for animals to roam, for there were few geographical barriers, such as mountains or ice caps, to contain them.

Yet, strangely, animals confined themselves. Studying a transect of Pangaea stretching from about three degrees south to 26 degrees north (a long swath in the center of the continent covering tropical and semiarid temperate zones), a team of scientists led by Jessica Whiteside at Brown University has determined that reptiles, represented by a species called procolophonids, lived in one area, while mammals, represented by a precursor species called traversodont cynodonts, lived in another. Though similar in many ways, their paths evidently did not cross.

“We’re answering a question that goes back to Darwin’s time,” said Whiteside, assistant professor of geological sciences at Brown, who studies ancient climates. “What controls where organisms live? The two main constraints are geography and climate.”

Turning to climate, the frequency of rainfall along lines of latitude directly influenced where animals lived, the scientists write in a paper published this week in the online early edition of the Proceedings of the National Academy of Sciences. In the tropical zone where the mammal-relative traversodont cynodonts lived, monsoon-like rains fell twice a year. But farther north on Pangaea, in the temperate regions where the procolophonids predominated, major rains occurred only once a year. It was the difference in the precipitation, the researchers conclude, that sorted the mammals’ range from that of the reptiles.

Reptile precursor

The skull of the procolophonid Hypsognathus was found in Fundy basin, Nova Scotia, which was hotter and drier when it was part of Pangaea. Mammals, needing more water, chose to live elsewhere.

The scientists focused on an important physiological difference between the two: how they excrete. Mammals lose water when they excrete and need to replenish what they lose. Reptiles (and birds) get rid of bodily waste in the form of uric acid in a solid or semisolid form that contains very little water.

On Pangaea, the mammals needed a water-rich area, so the availability of water played a decisive role in determining where they lived. “It’s interesting that something as basic as how the body deals with waste can restrict the movement of an entire group,” Whiteside said.

In water-limited areas, “the reptiles had a competitive advantage over mammals,” Whiteside said. She thinks the reptiles didn’t migrate into the equatorial regions because they already had found their niche.

The researchers compiled a climate record for Pangaea during the late Triassic period, from 234 million years ago to 209 million years ago, using samples collected from lakes and ancient rift basins stretching from modern-day Georgia to Nova Scotia. Pangaea was a hothouse then: Temperatures were about 20 degrees Celsius hotter in the summer, and atmospheric carbon dioxide was five to 20 times greater than today. Yet there were regional differences, including rainfall amounts.

The researchers base the rainfall gap on variations in the Earth’s precession, or the wobble on its axis, coupled with the eccentricity cycle, based on the Earth’s orbital position to the sun. Together, these Milankovitch cycles influence how much sunlight, or energy, reaches different areas of the planet. During the late Triassic, the equatorial regions received more sunlight, thus more energy to generate more frequent rainfall. The higher latitudes, with less total sunlight, experienced less rain.

The research is important because climate change projections shows areas that would receive less precipitation, which could put mammals there under stress. 

“There is evidence that climate change over the last 100 years has already changed the distribution of mammal species,” said Danielle Grogan, a graduate student in Whiteside’s research group. “Our study can help us predict negative climate effects on mammals in the future.”

Contributing authors include Grogan, Paul Olsen from Columbia University, and Dennis Kent from Rutgers. The National Science Foundation and the Richard Salomon Foundation funded the research.

  • Citation

  • Jessica H. Whiteside, Danielle S. Grogan, Paul E. Olsen, and Dennis V. Kent. 2011. Climatically driven biogeographic provinces of Late Triassic tropical Pangea. PNAS doi:10.1073/pnas.1102473108

    Friday, May 13, 2011

    A New, Terrestrial Crocodilian-like Reptile from Brazil's Late Cretaceous

    Souza Carvalho and colleagues (2011) have recently described Campinasuchus dinizi a new genus and species of baurusuchid (Crocodylifomes) based onsever skulls. This animal distinctive becasue of its relatively short, anteriorly tapering snout, differentiated maxillary teeth with the 3rd and 4th maxillary teeth extremely enlarged relative to other teeth, and the presence of a large anteroposterior depression on each palatine between the palatal fenestrae. It lived in an environment marked by long dry intervals interrupted by periods of heavy rains that created relatively deep lakes and temporary ponds during flood periods. The authors note that a remarkably diverse terrestrial mesoeucrocodylian fauna has been recovered from the continental Cretaceous of the Bauru Basin in fluvial and lacustrine deposits. Species of at least six distinct groups are now recognized, including notosuchids, sphagesaurids, candidodontids, peirosaurids, trematochampsids, and baurusuchids. All of these were mostly terrestrial crocodyliforms and they potentially developed ecological strategies that allowed them to live in a hot and arid climate in the Late Cretaceous of Brazil.
    The animal discussed in this article is a 
    baurusuchid mesoeucrocodylian. Above 

    is a related species, 
    Baurusuchus salgadoensis, a crocodile-like species, also 
    from the Upper Cretaceous of Brazil. Artist Credit: Nobu Tamura 

    Ismar de Souza Carvalho, et al. . 2011. Campinasuchus dinizi gen. et sp. nov., a new Late Cretaceous baurusuchid (Crocodyliformes) from the Bauru Basin, Brazil. Zootaxa 2871: 19–42

    Monday, May 9, 2011

    An Old Book With a Large Impact on Reptile Names

    Recently the Guardian carried a short blub about a re-print of a old book by Albert Seba. Albert Seba was an early 18th century pharmacist in Amsterdam who purchased natural history specimens from sailors in an effort to find exotic plant and animal products he could use for pharmacetitcal purposes. His interest expanded and he collected snakes, lizards, birds, insects, and mollscus. About 1711 he supplied drugs to the Russian court in Saint Petersburg and promoted his collection to the Russians. Early in 1716 Peter the Great bought Sebae's complete collection. In October 1728 Seba had become a Fellow of the Royal Society and he was visited by Carl Linne in 1735 Linnaeus. In 1752, several years after his death, Seba's second collection went on auction in Amsterdam. In 1734 Seba published a Thesaurus of animal specimens with exceptiopnal engravings. The Thesaurus' title had Latin and Dutch components: Locupletissimi rerum naturalium thesauri accurata descriptio — Naaukeurige beschryving van het schatryke kabinet der voornaamste seldzaamheden der natuur (Accurate description of the very rich thesaurus of the principal and rarest natural objects). The last two of the four volumes were published after Sebea's death (1759 and 1765). The original 446-plate volume is on permanent exhibit at the Koninklijke Bibliotheek in The Hague, Netherlands. Recently, a complete example of the Thesaurus sold for US $460,000 at an auction. In 2001, Taschen Books published a reprint of the Thesaurus, with a second printing in 2006. This reproduction is taken from a rare, hand-colored original. The introduction supplies background information about the fascinating tradition to which Seba's curiosities belongedAlbertus Seba's Cabinet of Natural Curiosities remains one of the most prized natural history books of all time.

    There are 15 reptiles that have a common name, synonym, or epithet that are based on Seba's name: Chironius fuscus (LINNAEUS, 1758); Eutropis carinata (SCHNEIDER, 1801); Eutropis multifasciata (KUHL, 1820); Laudakia stellio (LINNAEUS, 1758); Melanochelys trijuga (SCHWEIGGER, 1812); Ninia atrata (HALLOWELL, 1845); Ninia maculata (PETERS, 1861); Ninia sebae (DUMÉRIL, BIBRON & DUMÉRIL, 1854); Oplurus cuvieri GRAY, 1831; Oxyrhopus petola (LINNAEUS, 1758); Phalotris sansebastiani JANSEN & KÖHLER, 2008; Podarcis hispanicus (STEINDACHNER, 1870); Python natalensis SMITH, 1840; Python sebae (GMELIN, 1789); and Tupinambis rufescens (GÜNTHER, 1871).

    Friday, May 6, 2011

    The Spread of an Amphibian Epidemic, Bd in Mesoamerica

    Male (top) and female (bottom)
    Golden Toads, Incilius periglenes
    (Savage, 1967). Monteverde, Costa
    Rica. Described by science in 1967
    it is likely now extinct, the victim of
     Bd. This was a lower montane
    rainforest species. JCM
    Evidence suggests that we are seeing the start of the 6th mass extinction event in Earth's history, and some of the evidence comes from amphibians, 40% of which are considered endangered. Hypotheses have implicated habitat destruction, overexploitation, pollution, and climate change in the loss of amphibians, but the infectious fungal disease, chytridiomycosis, has been the main suspect in the disappearance of many different species in many different families in geographically distant locations. The chytridiomycete fungus Batrachochytrium dendrobatidis (Bd) has a flagellated infective life stage called the zoospore that penetrates the skin of amphibians causing hyperkeratosis, this results in a loss of skin function, osmoregulatory failure, and death. First reported in 1999, Bd has been shown to be closely associated with the collapse of amphibian populations in Australia, Panama, California, and Peru and has been linked to amphibian declines that occurred decades ago. Bd is unusual because multiple host species in at least one locality have been extripated before density-dependent factors could slow the spread of disease. Now, Tina Cheng and colleagues (2011) present evidience on how Bd has spread using museum specimens from vanished populations. Using two well-studied cases of amphibian decline in Mesoamerica: the decline and disappearance of anurans from Costa Rica’s Monteverde Reserve in the late 1980s, and the decline and disappearance of plethodontid salamanders from the mountains of southern Mexico and western Guatemala in the 1970s and 1980s, the authors test retroactively whether Bd emergence was linked to earlier declines and extinctions. They use a noninvasive PCR sampling technique that detects Bd in formalin-preserved museum specimens and found Bd using the PCR technique in 83–90% (n = 38) of samples that were identified as positive by histology. They examined specimens collected before, during, and after major amphibian decline events at established study sites in southern Mexico, Guatemala, and Costa Rica and found a pattern of Bd emergence coincident with decline at these localities. The absence of Bd over multiple years at all localities followed by the concurrent emergence of Bd in various species at each locality during a period of population decline. The geographical and chronological emergence of Bd at these localities suggests a southward spread from southern Mexico in the early 1970s to western Guatemala (1980s/1990s), and to Monteverde, Costa Rica (1987); thus the authors found evidence of a historical “Bd epidemic wave” that began in Mexico and subsequently spread to Central America. The full article is available on-line, follow the link below.


    Species Accumulate Over Time - Amazonian Treefrog Assemblages

    For more than two hundred years, the question of why there are more species in the tropics has been a biological enigma. A particularly perplexing aspect is why so many species live together in a small area in the tropics, especially at some sites in the rainforests of the Amazon Basin in South America.

    New research on the evolution and ecology of treefrogs, published online in the journal Ecology Letters, sheds new light on the puzzle. The patterns found in treefrogs may also help to explain the high species richness of other groups of organisms -- such as trees, birds and insects -- in the Amazon rainforests.

    "Treefrogs are a particularly important group to study for understanding amphibian diversity, because they can make up nearly half of all amphibian species in some rainforest sites," says lead author John J. Wiens, an Associate Professor in the Department of Ecology and Evolution at Stony Brook University. "Treefrogs also offer a striking example of the high local-scale biodiversity in the Amazon. At some sites in the Amazon rainforest, there are more treefrog species in a small area than there are across all of North America or Europe."

    The researchers compiled data on the number of treefrog species at 123 sites around the world and analyzed the data with a new evolutionary tree (based on DNA sequence data) for 360 treefrog species. They discovered that the richness of treefrog species in the Amazon rainforest sites is not explained by wet, tropical climatic conditions alone.

    "In fact, we found that many tropical rainforest sites that are outside the Amazon Basin have no more species than do some sites in temperate North America," explains Dr. Wiens.

    Instead, the researchers discovered that the high biodiversity of Amazonian sites is related to different groups of treefrogs occurring together in the Amazon Basin for more than 60 million years -- since before most dinosaurs became extinct. In contrast, those sites in tropical rainforests that have relatively few treefrog species are in areas that were colonized by treefrogs much more recently.

    These results also have important implications for humans. "The results suggest that the incredible biodiversity of amphibians in some sites in the Amazon Basin took more than 50 million years to develop," says Dr. Wiens. "If the Amazon rainforests are destroyed and the amphibian species are driven to extinction by human activities in the next few decades, it may take tens of millions of years for this incredible level of biodiversity to ever return.

    John J. Wiens, R. Alexander Pyron, Daniel S. Moen. Phylogenetic origins of local-scale diversity patterns and the causes of Amazonian megadiversity. Ecology Letters, 2011; DOI: 10.1111/j.1461-0248.2011.01625.x

    The Permian Extinction and Pareiasaurs

    Scutosaurus karpinskii, a pareiasaur from the Late 
    Permian of Russia. Artist Credit: Nobu Tamura 
    The following is a press release from the University of Bristol.

    The end-Permian extinction, by far the most dramatic biological crisis to affect life on Earth, may not have been as catastrophic for some creatures as previously thought, according to a new study led by the University of Bristol.

    An international team of researchers studied the parareptiles, a diverse group of bizarre-looking terrestrial vertebrates which varied in shape and size. Some were small, slender, agile and lizard-like creatures, while others attained the size of rhinos; many had knobbly ornaments, fringes, and bony spikes on their skulls.

    The researchers found that, surprisingly, parareptiles were not hit much harder by the end-Permian extinction than at any other point in their 90 million-year history. Furthermore, the group as a whole declined and diversified time and time again throughout its history, and it was not until about 50 million years after the end-Permian crisis that the parareptiles finally disappeared.

    During the end-Permian extinction, some 250 million years ago, entire groups of animals and plants either vanished altogether or decreased significantly in numbers, and the recovery of the survivors was at times slow and prolonged before new radiations took place.

    By studying the fossil record, palaeontologists can examine how individual groups of organisms responded to the end-Permian event and assess just how dramatic it was. However, as the quality and completeness of the fossil record varies considerably, both geographically and stratigraphically, palaeontologists need to find a way to ‘join the dots’ and piece together the fragments of a complex mosaic to give a more satisfactory and better picture of ancient life’s diversity.

    The team led by Dr Marcello Ruta of Bristol’s School of Earth Sciences, and including scientists from Germany, Brazil and North America, used the evolutionary relationships among known parareptiles to produce a corrected estimate of changing diversity through time.

    Dr Marcello Ruta said: “Evolutionary relationships can be superimposed on a time scale, allowing you to infer missing portions of past diversity. They are powerful tools that complement and refine the known record of extinct diversity. If you visualize evolutionary relationships in the form of branching diagrams and then plot them on a time scale, new patterns begin to emerge, with gaps in the fossil record suddenly filling rapidly.”

    One of the team members, Juan Cisneros of the Universidade Federal do Piauí, Ininga, Brazil said: “It is as if ghosts from the past appear all of a sudden and join their relatives in a big family tree – you have a bigger tree. This way, you can start analysing observed and extrapolated abundance of species through time, and you can quantify novel origination and extinction events that would otherwise go unnoticed if you were to look at known finds only.”

    Co-author Johannes Müller of the Museum für Naturkunde, Berlin added: “Researchers who investigate changing diversity through time have a huge battery of basic and advanced analytical and statistical methods at their disposal to study patterns of diversification and extinction. Classic text-book views of waxing and waning of groups through deep time will certainly benefit, where possible, from the use of evolutionary thinking.”
    University of Washington’s Linda Tsuji, also part of the research team, concluded: “This is the first time that the history of parareptiles has been examined in such detail. But this is only the beginning. These bizarre-looking vertebrates continue to inspire generations of researchers, not only those interested in mass extinctions. They are abundant, diverse, and we still know very little about their biology. We hope that this study will initiate a more in-depth study of the response of terrestrial vertebrates to global catastrophes.”

    The new findings are published online today in the journal Palaeontology.

    RUTA, M., CISNEROS, J. C., LIEBRECHT, T., TSUJI, L. A. and MÜLLER, J. (2011), Amniotes through major biological crises: faunal turnover among parareptiles and the end-Permian mass extinction. Palaeontology, 54: no. doi: 10.1111/j.1475-4983.2011.01051.x

    Thursday, May 5, 2011

    Abundance of Animals on Islands

    This is the finding of a new model developed by researchers from the University of Leeds and Imperial College London. The model could apply both to actual islands and isolated areas of habitat on the mainland that are home to unique species, such as the table top mountains of South America.

    The natural history of islands is littered with examples of unusual species found only in one place, such as the Hawaiian Goose, Galápagos Tortoises and Dodo that may once have been common on their islands, but since human contact have become rare or even extinct. Now this new modelling approach shows that in general, most unique island species should be common on their island. If they are not, then the researchers believe human activity is most likely to be the cause.

    "Models of island ecology have tended to focus on the total number of different species that you might expect to find on an island, rather than on how common or rare those species are and whether or not they are unique to the island," says Dr James Rosindell, of Leeds' Faculty of Biological Sciences. "Our model is able to predict the way that new species develop in isolation from the mainland as well as how many individuals of each species we could expect to see in their natural habitat. However, there is little data on population sizes and this highlights a real gap in knowledge that we need to fill."

    To develop the model, the researchers collated data on bird species found across 35 islands and archipelagos. Modern genetics makes it possible to identify which species have diverged to create new species - so the team were able to test their model against actual data.

    The model and data both show that whilst islands close to the mainland have no unique species, more distant islands tend to have unique species that are closely related to mainland species. Only the islands and archipelagos furthest from the mainland are expected to contain large numbers of unique species closely related to each other, such as Darwin's finches on the Galápagos and the Hawaiian honeycreepers.

    "This model is still in its early stages of development, but we hope it will help to prompt more study of population sizes on islands," says Dr Albert Phillimore, from Imperial's Department of Life Sciences. "Comparing the predictions of different models to actual data can help us to identify where other factors are coming into play - such as additional ecological processes and human intervention. In the future, we plan to look at how the model could also help make predictions relevant to conservation strategy."

    Wednesday, May 4, 2011

    Proteins Discovered in Mosasaur Bone

    Fossil – just stone? No, a research team in Lund, Sweden, has discovered primary biological matter in a fossil of an extinct varanoid lizard (a mosasaur) that inhabited marine environments during Late Cretaceous times. Using state-of-the-art technology, the scientists have been able to link proteinaceous molecules to bone matrix fibres isolated from a 70-million-year-old fossil; i.e., they have found genuine remains of an extinct animal entombed in stone.

    With their discovery, the scientists Johan Lindgren, Per Uvdal, Anders Engdahl, and colleagues have demonstrated that remains of type I collagen, a structural protein, are retained in a mosasaur fossil.

    The scientists have used synchrotron radiation-based infrared microspectroscopy at MAX-lab in Lund, southern Sweden, to show that amino acid containing matter remains in fibrous tissues obtained from a mosasaur bone.
    Bone matrix fibers in mosasaur bone (a) Histologic 
    preparation that shows how the fibres surrounds a 
    vascular duct. (b) SEM-picture that shows etched 
    fibres. (c) Detail of histologic preparation showing
     fibres encapsulated in bioapatite. (d) Histo-chemical
     stain (blue) showing that the fibres contain biological 
    matter.Photo: Johan Lindgren

    Previously, other research teams have identified collagen-derived peptides in dinosaur fossils based on, for example, mass spectrometric analyses of whole bone extracts.

    The present study provides compelling evidence to suggest that the biomolecules recovered are primary and not contaminants from recent bacterial biofilms or collagen-like proteins.

    Moreover, the discovery demonstrates that the preservation of primary soft tissues and endogenous biomolecules is not limited to large-sized bones buried in fluvial sandstone environments, but also occurs in relatively small-sized skeletal elements deposited in marine sediments.

    A paper reporting the discovery, Microspectroscopic Evidence of Cretaceous Bone Proteins is now available in the scientific journal PLoS ONE

    Lindgren J, Uvdal P, Engdahl A, Lee AH, Alwmark C, et al. (2011) Microspectroscopic Evidence of Cretaceous Bone Proteins. PLoS ONE 6(4): e19445. doi:10.1371/journal.pone.0019445.