Thursday, July 19, 2012

Frog Deformities & Disease



Climate change, habitat destruction, pollution and invasive species are all involved in the global crisis of amphibian declines and extinctions, researchers suggest in a new analysis, but increasingly these forces are causing actual mortality in the form of infectious disease.

Amphibians are now, and always have been hosts for a wide range of infectious organisms, including viruses, bacteria and fungi, scientists said in a review published in Philosophical Transactions of the Royal Society B.

But in recent decades, disease seems to have taken a more prominent role in causing mortality. Because of multiple stresses, many induced by humans, amphibians now succumb to diseases they may historically have been better able to resist or tolerate.

"There's more and more evidence of the role of disease in the biodiversity crisis, in both amphibians and other types of animals," said Andrew Blaustein, a distinguished professor of zoology at Oregon State University and author of the recent analysis.

"It's normal for animals to deal with infectious organisms, often many of them simultaneously," he said. "But in the face of pollution, a reduced immune response, climate change, evolving pathogens and many other stresses in such a short period of time, many species now simply can't survive."

The current extinction rates of amphibians -- which existed even before dinosaurs roamed Earth -- may be more than 200 times the background rate of extinction, the scientists note in this report. From an evolutionary perspective, amphibians that survived for hundreds of millions of years may be undergoing a major extinction event.

Because they have both terrestrial and aquatic life stages amphibians are exposed to various environmental forces more than some other animals, scientists say, and a higher percentage of them are threatened with extinction than are birds or mammals. However, similar concerns may become apparent in many animal species, including humans, as environmental changes and stresses grow, they said.

Among the observations in this report:

• Infectious disease around the world is increasing at an unprecedented rate.

• Natural stresses such as competition and predation have been joined by human-induced stresses, ranging from pollution to global warming.

• These forces can reduce immune competence in amphibians, even as climate change, invasive species and other factors increase pathogen spread, persistence, growth and mortality.

• Some amphibians deal with stress by hormonal changes such as increased production of glucocorticoids, but on a sustained basis, that approach can further suppress their immune system.

• Warmer winters and night-time temperatures may reduce the cycle of pathogen die-offs that would naturally occur in colder regions.

These forces are complex, the researchers noted. The effects of climate change on amphibian disease, for instance, my cause some pathogens to increase in prevalence and severity, while others decline.

Understanding the driving forces behind these changes, the scientists said, will be important not only to address amphibian declines but also to deal with emerging infections in many other plants and animals, including humans. Such impacts can affect wildlife conservation, economic growth and human health.

Citation
Andrew R. Blaustein, Stephanie S. Gervasi, Pieter T. J. Johnson, Jason T. Hoverman, Lisa K. Belden, Paul W. Bradley, and Gisselle Y. Xie. 2012. Ecophysiology meets conservation: understanding the role of disease in amphibian population declines. Phil. Trans. R. Soc. B, June 19, 2012 DOI: 10.1098/rstb.2012.0011 pages 1471-2970.


Thursday, July 12, 2012

The Herpetofauna Extinction Crisis

The following is a press release from the Center for Biological Diversity.

Amphibians and reptiles are amazing creatures with clever adaptations that have allowed them to brave the millennia. Consider the Coachella Valley fringe-toed lizard’s scaly hind toes, which resemble snowshoes and keep the lizard from sinking into sand as it sprints away from predators; or the eastern diamondback rattlesnake’s heat-sensing pit organ, which helps it find the small, warm-blooded prey on which it feeds. Such diversity is vital to functioning ecosystems and enriches humankind’s enjoyment of the natural world.

But today, the world’s herpetofauna are among the most imperiled species on Earth. Ubiquitous toxins, global warming, nonnative predators, over collection, habitat destruction and disease are key factors leading to their demise. Globally, 664 species of reptiles, or more than 20 percent of the total evaluated species, are endangered or vulnerable to extinction, according to the International Union for Conservation of Nature’s 2011 Red List. The situation is worse for amphibians. More than 1,900 species of frogs, toads and salamanders — fully 30 percent of the world’s amphibians — are at risk of dying out. Moreover, scientists lack sufficient information to assess the status of nearly 25 percent of the world’s herps. These species are slipping away faster than scientists can study them.

The Center outdid ourselves in protecting these amazing creatures on July 11, 2012, when we made the biggest-ever move to protect amphibians and reptiles in the United States, filing a mega-petition requesting Endangered Species Action protection for 53 amphibians and reptiles in 45 states. The petition asks the U.S. Fish and Wildlife Service to protect six turtles, seven snakes, two toads, four frogs, 10 lizards and 24 salamanders under the Act. To learn more about amphibians and reptiles, read our FAQ and then sign up for future alerts about how you can help save species.

Almost since its inception, the Center has worked to protect reptiles and amphibians. By filing petitions that urge federal wildlife agencies to provide Endangered Species Act protection for imperiled herps — and following up with lawsuits when necessary — the Center has obtained federal safeguards and critical habitat for dozens of amsphibians and reptiles, from the Chiricahua leopard frog to the Mississippi gopher frog to the Tucson shovel-nosed snake.

Stemming the herpetofauna extinction crisis means attacking it on every front; the Center’s conservation efforts are almost as diverse as the animals we’re working to protect. To reduce impacts of toxic pesticides on the California red-legged frog, the Center secured a settlement with the U.S. Environmental Protection Agency that prohibits the use of 66 toxic pesticides near core habitats. And a follow-up lawsuit against the U.S. Fish and Wildlife Service seeks permanent restrictions on these deadly toxins. The Center’s campaign for fish-stocking reform aims to protect the Sierra Nevada yellow-legged frog and other amphibians from nonnative trout, while litigation against the Forest Service has helped curb grazing-driven habitat destruction for the Oregon spotted frog.

While threats like our warming climate require efforts across the globe, threats like human persecution can be addressed by working at the level of communities or regions. For example, the eastern diamondback rattlesnake is facing population declines due in part to “rattlesnake roundups,” which are contests calling for hunters to collect (and later kill) as many snakes as they can in a year. Through our campaign to outlaw rattlesnake roundups, the Center aims to convince local communities to turn these gruesome contests into wildlife appreciation festivals. Freshwater turtles are also being threatened by human persecution, namely by overcollection for the food and the pet trade. Our successful ongoing campaign on behalf of southern and midwestern turtles has prompted several states to regulate turtle harvest, an important step toward reversing their alarming declines.

Though amphibians and reptiles represent some of the most rapidly disappearing species on Earth, they’ve long been underrepresented when it comes to wildlife protection. So in 2010, the Center made certain that animals like the California tiger salamander have their very own champion by hiring the nation’s first full-time attorney dedicated to conserving herpetofauna.

Wednesday, July 4, 2012

Suzio Report - Late June

Howdy Herpers,                                                        07/03/12

First off, happy birthday to Dennis Caldwell. I hope you will all check in and wish him well. The dude is like Peter Pan--he never grows up, and never grows old. Have a good one buddy, and live forever!

We had an interesting weekend. What's the point in having an interesting weekend if we can't broadcast it to 300 of you?

On Saturday morning, Patti Mahaney and I assailed the Valley of the Truly Happy. Patti was kind enough to find us a cerberus, which is the reason for going there. Then, on Saturday night, Mr. Slone led me up our hill, down our hill, back up our hill, and back down our hill. Then we went to the far NE side of our hill, and then headed a kilometer or so west. Yup--the herps are moving all over the place now. And with so many new ones, we have no clue as to which way they are traveling. 


This makes for much flandickery and excessive boot and body wear when tracking them.

We'll let the pictures tell part of the story.

Pics 1 and 2: Patti's cerberus. A GORGEOUS male.





Pics 3 and 4: Our female atrox #121, "Tracy." The first image was taken on 24 June. She looks in need of a plot biscuit. The second was as we found her on 30 June. 
She got a plot biscuit!



Pics 5 and 6: Our new tiger female #CT12. This is the first we have seen of her since releasing her in early June. If you look at the rattle in the first image, you will see that there are 2 uncolored rattles downstream of the basal. This would indicate a recent shed. In fact, I would guess that all of our snakes have shed recently. The second image is where she settled down and waited for us to leave.She traveled from the top of the hill, near AD5, all the way to the bottom of the southeast side of the hill.

Pics 7 and 8: Our molossus #10, "Susan." What the image doesn't show is the strips of our flesh being gaily festooned to the catclaw jungle that rises above her. Two of our molossus seem to heavily favor catclaw, which may be why we find so few of them out there. It's hard to herp inside those pernicious plants.

Pics 9 and 10:  Now there's something you don't see every day! A nice leopard lizard snoozing away in a creosote bush. This is the first Gambelia to be seen on the plot in over a year and a half. What a way to find one. Check out that last image. He's kind of letting it all hang out!

That's about all that's fit to spit. We are expecting some major cloudbursts tonight, and I'm very hopeful that forecast holds up. Could be a gorgeous morning in paradise tomorrow.

Best to all, and happy 4th!

roger

Were All Dinosaurs Feathered?



The new fossil find from the chalk beds of the Franconian Jura evokes associations with a pet cemetery, for the young predatory dinosaur reveals clear traces of fluffy plumage. It also poses an intriguing question: Were all dinosaurs dressed in down?

The fossil of the fledgling saurian, probably newly hatched when it met its end, is remarkable in many ways. First of all, juveniles are extremely rare in the dinosaur fossil record, so every new discovery provides insights into dinosaur nurseries. Moreover, this specimen is perhaps the best-preserved predatory dinosaur that has yet been found in Europe. And Sciurimimus albersdoerferi, which lived during the Jurassic Period some 150 million years ago, displays one very striking feature – its whole body must have been covered with a thick plumage of feathers.

All the feathered dinosaurs so far described belonged to the lineage that gave rise to modern birds. “However, Sciurumimus belongs to a much older branch of the family tree of predatory dinosaurs,” says LMU paleontologist Dr. Oliver Rauhut, who is also affiliated with the Bavarian State Collection for Paleontology and Geology, and led the investigation into the structure and affinities of the sensational new find. “Its plumage may be telling us that all predatory dinosaurs had feathers.”

Were all dinos decked out with feathers?
Several fossil finds have revealed that the pterosaurs – which were capable of flight and are the closest relatives of the dinosaurs – bore hair-like plumage on their bodies. Their fluffy coats resemble the downy feathers that can be recognized in the new fossil. This observation is very significant, as it suggests to the researchers that not just the pterosaurs and the predatory dinosaurs, but all dinosaurs may have had feathers. “If that is the case, we must abandon all our notions about giant reptiles encased in tough scales,” Rauhut says.

As the German-American research team led by Rauhut has been able to show, the new specimen represents a young megalosaur. The genus name Sciurumimus means “squirrel-like“ and refers to the animal’s bushy tail, while the species designation albersdoerferi honors the private collector who made the fossil available for scientific study. “When the skeleton was irradiated with UV light, we were able to discern fragments of the skin and the plumage as fluorescent spots and filaments,” says co-author Dr. Helmut Tischlinger.

Cute little dino kids
The juvenile Sciurumimus tells us even more. For instance, as in the case of other dinosaurs, its eyes were proportionately much larger than those of adult animals. In other words, young dinosaurs conformed to the “babyface” model. Secondly, it has long been suspected that not just the form of a dinosaur’s face, but also its whole mode of life, was subject to change during lifetime. “And indeed, this individual has a very different set of teeth from those found in adult megalosaurs,” says Rauhut. “That enables us to conclude that their diets also changed as they got older.”

The young Sciurumimus, with its slender, pointed teeth probably preyed on insects and small animals. Fully grown megalosaurs, on the other hand, often exceeded 6 m in length and may have weighed more than a ton, and could give other large dinosaurs a good run for their money. That may also be true of the new species. “We know that dinosaurs were able to grow at terrific rates; diminutive hatchlings could reach adult lengths of several meters,” Rauhut points out. “And even if they might have looked fluffy, they were certainly among the top predators in the food chain.”

Citation
Oliver W. M. Rauhut, Christian Foth, Helmut Tischlinger, and Mark A. Norell. 2012. Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany PNAS doi:10.1073/pnas.1203238109

Tuesday, July 3, 2012

3. Field Notes From Tobago


Little Tobago Island is located off the northeast coast of Tobago, it is about 97 hectares, and contains seasonal and littoral forests. Birds of Paradise were once introduced here, they have now been extirpated and are replaced by feral domestic chickens. We made a day visit to the island on June 29 and observed some of the herpetofauna. The most obvious species is Ameiva atrigularis, these lizards are relatively tame, sit quietly on a trail and they will approach you, and some specimens are quite large. There is relatively little beach habitat on the island, but there is a small stretch of sandy beach next to the jetty where Cnemidophorus lemniscatus is present. Gonatodes ocellatus can be seen sitting on tree trunks in the shade. Iguanas are also present, and usually a fleeting glimpse is all you see.  We failed to find Bachia heteropa and Hemidactylus palaichthus species previously reported by Dinsmore (1970) and Murphy (1997).
Ameiva atrigularis foraging on Little Toabo
Cnemidophorus lemniscatus on Little Tobago
As for the snakes, we found only Mastigodryas dunni, a species also present on Tobago. Other snakes reported from the island are: Atractus trilineatus and  Leptophis coeruleodorsus.
Mastigodryas dunni from Little Tobago
Frogs are problematic on Little Tobago. Mannophryne olmonae and Leptodactylus fuscus have both been reported from the island by Murphy (1997) but we have been unable to confirm their presence. Freshwater is in short supply, streams are few and intermittent.  

Surprisingly absent from the island are: marine toads and any member of the genus Anolis.

Climate Change & Leatherbacks

For eastern Pacific populations of leatherback turtles, the 21st century could be the last. New research suggests that climate change could exacerbate existing threats and nearly wipe out the population. Deaths of turtle eggs and hatchlings in nests buried at hotter, drier beaches are the leading projected cause of the potential climate-related decline, according to a new study in the journal Nature Climate Change by a research team from Drexel University, Princeton University, other institutions and government agencies.

Leatherbacks, the largest sea turtle species, are among the most critically endangered due to a combination of historical and ongoing threats including egg poaching at nesting beaches and juvenile and adult turtles being caught in fishing operations. The new research on climate dynamics suggests that climate change could impede this population’s ability to recover. If actual climate patterns follow projections in the study, the eastern Pacific population of leatherback turtles will decline by 75 percent by the year 2100.

“We used three models of this leatherback population to construct a climate-forced population dynamics model. Two parts were based on the population’s observed sensitivity to the nesting beach climate and one part was based on its sensitivity to the ocean climate,” said the study’s lead author Dr. Vincent Saba, a research fishery biologist with the NOAA National Marine Fisheries Service Northeast Fisheries Science Center, visiting research collaborator at Princeton University, and a Drexel University alumnus.

Leatherback turtle births naturally ebb and flow from year to year in response to climate variations, with more hatchlings, and rare pulses of male hatchlings, entering the eastern Pacific Ocean in cooler, rainier years. Female turtles are more likely to return to nesting beaches in Costa Rica to lay eggs in years when they have more jellyfish to eat, and jellyfish in the eastern Pacific are likely more abundant during cooler seasons. Turtle eggs and hatchlings are also more likely to survive in these cooler, rainier seasons associated with the La Niña climate phase, as this research team recently reported in the journal PLoS ONE. In addition, temperature inside the nest affects turtles’ sex ratio, with most male hatchlings emerging during cooler, rainier seasons to join the predominantly-female turtle population.

The researchers applied Saba’s combined model of these population dynamics to seven climate model projections assessed by the Intergovernmental Panel on Climate Change (IPCC). The climate model projections were chosen based on their ability to model El Niño Southern Oscillation (ENSO) patterns on the temperature and precipitation in the region of Costa Rica where this team has conducted long-term leatherback studies.

The resulting projections indicate that warmer, drier years will become increasingly frequent in Central America throughout this century. High egg and hatchling mortality associated with warmer, drier beach conditions was the most significant cause of the projected climate-related population decline: This nesting population of leatherbacks could decline by 7 percent per decade, or 75 percent overall by the year 2100.

The population is already critically low.

“In 1990, there were 1,500 turtles nesting on the Playa Grande beach,” said Dr. James Spotila, the Betz Chair Professor of Environmental Science in the College of Arts and Sciences at Drexel. “Now, there are 30 to 40 nesting females per season.”

Spotila, a co-author of the study, has been studying leatherback turtles at Playa Grande in Costa Rica, the largest leatherback nesting beach in the eastern Pacific, with colleagues and Drexel students, for 22 years.

Poaching of turtle eggs was a major cause of the initial decline, and was once such a widespread problem that virtually no turtle hatchlings would survive at Playa Grande. Spotila and colleagues worked with the local authorities in Costa Rica to protect the leatherbacks’ nesting beaches so that turtle nests can hatch in safety. Bycatch of juvenile and adult turtles in fishing operations in the eastern Pacific remains a threat.

For the population to recover successfully, Spotila said, “the challenge is to produce as many good hatchlings as possible. That requires us to be hands-on and manipulate the beach to make sure that happens.”

Spotila’s research team is already investigating methods such as watering and shading turtle nests that could mitigate the impact of hot, dry beach conditions on hatching success.

Citation
Vincent S. Saba, Charles A. Stock, James R. Spotila, Frank V. Paladino & Pilar Santidrián Tomillo. 2012. Projected response of an endangered marine turtle population to climate change. Nature Climate Change doi:10.1038/nclimate1582.

Saturday, June 30, 2012

2. Field Notes From Tobago

After a rather poor two weeks of collecting herps in northern Tobago, we moved to Crown Point in southern Tobago. One of the goals is to produce a list of species that use mangrove forests on Tobago. Yesterday evening was quite productive in mangroves. The list of species includes: the marine toad, Rhinella marina; the whistling frog, Leptodactylus fuscus; Garman's frog, L. validus; the house gecko, Hemidactylus mabuya; Richard's anole, Anolis richardii; and Ruschenberger's tree boa, Corallus ruschenbergeri. Most disturbing was a large butchered green sea turtle with only a maggot covered carapace remaining. This is the week of fishermen's festivals in T&T which are ritual celebrations of bountiful sea turtle harvests. The fishermen's fet's have now changed from slaughtering sea turtles, to music festivals. But based on what we found last night the change has only been for some; others continue to kill and sell sea turtles for meat. Poaching sea turtles appears to be under control in Trinidad, but out of control in Tobago. The demand for bush meat here is considerable and there is a strong hunting lobby that keeps the price for a hunting license and fines for violations low.
The turtle was found right at the entrance to Bon Accord Lagoon, below Mike Rutherford curator at the UWI Museum of Zoology posses next to the turtle carapace..
The turtle shell was found by its rancid odor.

Monday, June 25, 2012

Field Notes from Tobago


Some readers may have noticed an absence of activity on this blog, this is due to my field schedule for the summer and the generally poor internet connections available in Charlottville, Tobago. We have been sitting in a beach house for a week doing daytime hikes, snorkeling, and hanging out with the locals with few signs of the island’s unique herpetofauna.   Day time walks along streams and nighttime trail and stream walks have produced few frogs, lizards or snakes. During the day Ameiva atrigularis is highly visible as is the ever present Anolis richardii . An occasional glimpse of an iguana, an iguana nest, or locals hunting them is also a reminder that we are in the Neotropics. But, there has been no significant rain since we arrived a week ago.
One interesting observation on A. richardii, is that there appear to be two morphs of males: one that is exceptionally large (120 mm) and often has white head markings and another that is smaller (about 70 mm) that appears to be mature with a well-developed yellow dewlap and hemipenal bulges in the tail. In early and mid-morning these lizards are sitting on vertical surfaces such as tree trunks, stream banks and road-cuts.
The snakes have been hiding. 

Gabe caught a small Ruschenberger’s treeboa on a night walk along Frenchmen’s River and while walking the Blood Bay River yesterday we found a Liophis melanotus neosus on a gravel bar in the river. It died because it had been run over by a Ford Pickup truck that was parked 20 meters away – road kill in a river. 
And, Stevland found a nice melanistic Spilotes pullatus, just short of two meters in total length. 
Mike retrieved a greater windward skink, Copeoglossum aurlae from under the bark of a tree while looking for gastropods (evidence is accumulating that this species is quite arboreal).
Frogs have been present but usually the species associated with disturbed habitats. Leptodactylus fuscus can be heard continually along roads; Hypsiboans cepitans is also present in small choruses. The North Side Road was very productive last year but this year a landslide closed the road a short distance from Charlottville. The slump backed up water in the ditch and frogs ready to exploit any body of water have been chorusing here is good numbers. Of interest is Leptodactylus validus which have laid its eggs on the flooded road with females standing guard over their tadpoles.

During stream walks the glass frogs were calling from the canopy and Mike Rutherford managed to find one at eye level. One of the Glasgow students also found a tiny (9 mm) hylid that may be a metamorph of Trachycephalus typhonius. And of course, marine toads are ever present in streams, forests, and the local bars.

The trails above the fishing village are narrow and the terrain is steep, but within a few minutes we found several calling male Pristimantis charlottvillensis and a six millimeter frog that is probably Prisimantis urichi or P. turpinourm – Leptodactylus fuscus and L. validus are here also.

So, the rains have now started and with a little luck the frog and snake activity will pick up tonight.

An Outing With the TTFNC


On 16 June we spent an evening looking for herps with a group from the Trinidad and Tobago Field Naturalists Club and the Glasgow Zoological Expedition. The activities were restricted to the Lopinot Valley. We walked the river, searched small streams, and visited an abandoned building foundation that was flooded and contained a huge assemblage of frogs with about 10 chorusing species. Here are a few photos from the evening.







Saturday, June 16, 2012

Rediscovery of A Thought to be Extinct Toad


The problem with declaring a species extinct is that they are often not. In 2004 the IUCN listed Adenomus kandianus, a Sri Lankan bufonid, as extinct because it has not been recorded for over 100 years, and field work during the previous decade failed to find the toad.

Adenomus kandianus Günther (1872) was previously known only from two specimens in the British Museum. The species is endemic to Sri Lanka, and the original description gave the type locality as "Ceylon" (= Sri Lanka). The epithet suggests that it might have been collected in the vicinity of the city of Kandy, central Sri Lanka. The Kandy Toad was known only from the type specimen and one syntype until Mendis et al. (2012} reported its rediscovery.

Claims that small animals are extinct are always problematic given that populations may exist outside of the known range, the ability of many animals to enter stasis for long periods of time, and that often the animals are difficult to distinguish from their close relatives.

Citation
L. J. MENDIS WICKRAMASINGHE, DULAN RANGA VIDANAPATHIRANA & NETHU WICKRAMASINGHE (Sri Lanka): Back from the dead: The world’s rarest toad Adenomus kandianus rediscovered in Sri Lanka Zootaxa 3347: 63–68.

Saturday, June 9, 2012

The Enigmatic Horned Anole

The horned anole, Anolis proboscis was originally described in 1956 by Peters and Orces from mid-altitudes on the western slopes of the Andes in Pichincha, Ecuador. Now Losos et al. (2012) have rediscovered the species in the general vicinity of the type locality. These include several females, which lack the conspicuous rostral appendage seen in males. Despite rediscovery, the natural history of the horned anole remains almost completely unknown. The authors conducted an ecological and behavioral study of this species near Mindo, Ecuador and found it to be an extremely slow-moving and cryptic species that often occurs high in the trees. The rostral horn of the males aside, A. proboscis is indistinguishable from Greater Antillean anoles of the “twig” ecomorph class in morphology, ecology, and behavior. The horn is soft and highly flexible and thus unsuitable for use as a weapon in male–male combat; hence, the horn most likely serves as a signal and may be involved in mate choice or territorial displays. However, the anole was not observed in any social encounters and this idea has not been tested. Given its cryptic morphology and behavior, it is not surprising that A. proboscis is so rarely observed. It is now known from four localities around the town of Mindo, Pichincha province. The furthest localities are only 13 km away from each other and investigations of nearby areas for this species have not yielded results. Current thinking is that the species range is about 33 square kilometers and no more than 200 square kilometers at altitudes between 1200 and 1650 m above sea level. The horned anole is a montane forest specialist although it has been collected in pasture land and secondary forest. It is a cryptic, slow-moving, species of the forest canopy and it has been named for its proboscis, an appendage used in courtship. The entire artcle can be found on-line. 

Friday, June 8, 2012

Proposed Legislation to Control Python bivittatus in Florida

The following is from the Orlando Sentinel.

U.S. Rep. Alcee Hastings, D-Miramar, has introduced the Stopping Non-Native Animals from Killing Endangered Species (SNAKES) Act that sounds crazy but he insists could work: it would send specially trained dogs into the Everglades to sniff out, track down and direct hunters to the Burmese pythons and other non-native constrictor reptiles that are proliferating in the Glades.

Here’s excerpts from the release:

“The Florida Everglades, one of the world’s largest wetland systems and one of America’s most precious ecosystems, is under attack by the Burmese python and other large constrictor snakes. It is estimated to now hold tens of thousands of pythons that are devastating natural wildlife and endangered species living in the Everglades. In some instances, mammal populations are down 90 percent from just a few years ago.

“Auburn University EcoDogs, working along with federal, state, county, tribal government entities, universities, and non-profit stakeholders, recently trained dogs for a study to assess whether detection dogs were an effective tool for python management efforts. As it turned out, dog search teams can cover more distance and have a higher accuracy rate in particular scenarios than human searchers. The SNAKES Act authorizes the Secretary of the Interior to work with stakeholders to establish this detection program full-time. 
“Once the dog indicates that a snake is in the area, it is taken a safe distance away while a human handler captures the snake. This way, the dogs never approach the snakes and are never placed in a position of danger. This dog detection team is a great tool that can help prevent what has happened in the Everglades from happening elsewhere in the United States, as well as assist in containing the snakes populations that are already out there. I urge my colleagues in Congress to support this legislation, and help to protect and restore one of the most unique natural ecosystems.”

Wednesday, June 6, 2012

MORE RATTLERS BITING; IS VENOM MORE TOXIC?

The following is from the U-T San Diego News

More San Diegans are being bitten by rattlesnakes, and the venom seems to be getting more toxic, health officials say.

“While San Diego County is seeing a rise in snake bite cases each year, the more alarming factor is the toxicity of the bite,” Dr. Richard Clark, director of the Division of Medical Toxicology at UC San Diego Health System, said Monday.

“We don’t know for sure that the rattlesnake venom is more toxic, but it appears that way because the symptoms and the wounds we’re seeing are worse than in the past,” said Clark, who also is medical director for the San Diego office of the California Poison Control System.

Last year, 40 people in the county were treated for rattlesnake bites, according to the county Emergency Medical Services, compared with 30 people in 2010, 27 people in 2009 and 24 people in 2008.

And the numbers have jumped this year, with 15 people treated for rattlesnake bites in the first four months of 2012, including 10 people just in April, county records show. For the same period in 2011, four people were bitten.

Clark said he wasn’t surprised that the number jumped in April, when warm weather draws out both snakes and hikers to the county’s backcountry. And while toxin levels in the venom typically are stronger during the summer when snakes are active, no one knows why it may be getting more potent.

“Some speculate that with the modern world encroaching on nature, it could be survival of the fittest. Perhaps only the strongest, most venomous snakes survive,” Clark said.

“A snake’s venom also changes depending on what it’s eating and the temperature of the day. That makes every bite difficult to predict.”

While about a quarter of bites may be “dry” or not contain venom, a venomous bite can be serious or deadly. Symptoms of severe bites, which are always painful, usually start quickly and can include nausea, blurred vision, and then swelling in the mouth and throat that can make breathing difficult. Within minutes, victims can get lightheaded, collapse and go into shock.

“For anyone who suspects a bite, their next move should be to a hospital emergency department,” Clark said.

Patients are given a series of antivenin shots, which cost about $2,500 per vial, and remain hospitalized until they’re stabilized, he said.

The Weight of Giraffatitan brancai

Giraffatitan brancai
Scientists have developed a new technique to accurately measure the weight and size of dinosaurs and discovered they are not as heavy as previously thought.

University of Manchester biologists used lasers to measure the minimum amount of skin required to wrap around the skeletons of modern-day mammals, including reindeer, polar bears, giraffes and elephants.

They discovered that the animals had almost exactly 21% more body mass than the minimum skeletal 'skin and bone' wrap volume, and applied this to a giant Brachiosaur skeleton in Berlin's Museum für Naturkunde.

Previous estimates of this Brachiosaur's weight have varied, with estimates as high as 80 tonnes, but the Manchester team's calculations – published in the journal Biology Letters – reduced that figure to just 23 tonnes. The team says the new technique will apply to all dinosaur weight measurements.

Lead author Dr Bill Sellers said: "One of the most important things palaeobiologists need to know about fossilised animals is how much they weighed. This is surprisingly difficult, so we have been testing a new approach. We laser scanned various large mammal skeletons, including polar bear, giraffe and elephant, and calculated the minimum wrapping volume of the main skeletal sections.

"We showed that the actual volume is reliably 21% more than this value, so we then laser scanned the Berlin Brachiosaur, Giraffatitan brancai, calculating the skin and bone wrapping volume and added 21%. We found that the giant herbivore weighed 23 tonnes, supporting the view that these animals were much lighter than traditionally thought.

Dr Sellers, based in Manchester's Faculty of Life Sciences, explained that body mass was a critical parameter used to constrain biomechanical and physiological traits of organisms.

He said: "Volumetric methods are becoming more common as techniques for estimating the body masses of fossil vertebrates but they are often accused of excessive subjective input when estimating the thickness of missing soft tissue.

"Here, we demonstrate an alternative approach where a minimum convex hull is derived mathematically from the point cloud generated by laser-scanning mounted skeletons. This has the advantage of requiring minimal user intervention and is therefore more objective and far quicker.

"We tested this method on 14 large-bodied mammalian skeletons and demonstrated that it consistently underestimated body mass by 21%. We suggest that this is a robust method of estimating body mass where a mounted skeletal reconstruction is available and demonstrate its usage to predict the body mass of one of the largest, relatively complete sauropod dinosaurs, Giraffatitan brancai, as 23,200 kg.

"The value we got for Giraffatitan is at the low range of previous estimates; although it is still huge, some of the enormous estimates of the past – 80 tonnes in 1962 – are exaggerated. Our method provides a much more accurate measure and shows dinosaurs, while still huge, are not as big as previously thought."

Tuesday, June 5, 2012

Neotropical Snakes That Span Gaps


Imantodes cenchoa

 Arboreal snakes can extend their bodies up to 50% of their length to bridge a gap between branches or perches under laboratory conditions. Morphological adaptations associated with this including lateral compression of the body, elongation of the tail, widening of ventral scales, forward-facing eyes that also can be aimed downward, and reduction in relative mass and the most agile species possess rigid muscles and tight skin, providing for more controlled movements and cantilevering. Specialized behaviors also play an adaptive role, but have been studied less because of the logistic difficulties of accessing and working in arboreal habitats.  A recent examination of cantilevering by Ray (2012) in adult snakes from Omar Torrijos National Park in Coclé Province, Panama used: Dipsas sp., Imantodes cenchoa, Oxybelis brevirostris, Sibon argus and S. annulatus. Also included were several less abundant species that were tested opportunistically and included I. inornatus, Leptodeira septentrionalis, and S. nebulatus. Species of Imantodes and Sibon exhibited the greatest ability to bridge distances in the experiments and they show the more highly adapted morphologically for arboreal habits. These species able to exploit smaller twigs, which facilitates movement between the ends of branches and subsequent cantilevering, presumably allowing these species to exploit food resources other snakes have difficulty reaching.

Citation
Ray, J.M. 2012. Bridging the gap: interspecific differences in cantilevering ability in a Neotropical arboreal snake assemblage. South American Journal of Herpetology 7:35-40.