Wednesday, March 16, 2011

British Herps Disappearing

The following is based on a BBC article by Emma Brennand

The native adder is effectively disappearing from our landscape, a study has revealed.

The first nationwide survey of UK amphibian and reptiles has found that Britain's most widespread snake, the adder, is in decline.

Slow worms, common lizards and grass snakes are also becoming less widespread, as are the common toad, common frog and the great crested newt.

The only species found to be increasing its range is the palmate newt.

Dr John Wilkinson explains how to spot a common toad

These startling trends come from a report produced by the Amphibian and Reptile Conservation (ARC) Trust, which has been gathering data on 12 species since 2007.

The trust's National Amphibian and Reptile Recording Scheme (NARRS) has presented its interim findings, which cover the first half of the six-year survey period from 2007 to 2012.

The full survey aims to establish baselines for widespread species - figures against which future status changes can be assessed.

The survey focuses on widespread amphibian and reptile population. These include the great crested, smooth and palmate newts, common toad and frog, common lizard, slow-worm, grass snake and adder, as well as the wall and green lizards and agile frog in Jersey.

The rarest species, such as the great crested newt, already have high levels of protection, but it is strongly suspected that some formerly common species now in decline.

For this reason, the UK government passed legislation in 2007 prioritising the protection of common toads and all UK reptiles.

But this survey suggests that their numbers continue to fall.

Out of approximately 250 square kilometres surveyed, adders were found in about 20.

Our reptiles and amphibians are doing poorly, adders in particular are of concern

"Though we suspected that adders were getting much less common, it is very alarming that they turn up in only 7% of reptile surveys nationally," Dr John Wilkinson, Research and Monitoring Officer for the Amphibian and Reptile Conservation Trust, told BBC News.

"Adder occupancy is poor everywhere, making them our rarest widespread reptile by far and in need of serious conservation attention."

Historically, it was believed that adders were most at risk from persecution - people killing the snakes because they are venomous. But the ARC Trust say that their decline may also be caused by development and disturbance.

Other widespread amphibians and reptiles also appear to be in trouble.

"There is no single trend as different species are sensitive to different issues," explained Dr Wilkinson.

"Broadly, though, our reptiles and amphibians are doing poorly and adders in particular."

Common frogs are becoming less common in the south of England, particularly in areas which have experienced the most development in recent decades.

And, in the same area of England, the common toad is only half as widespread as the common frog.

"Great crested newts may be much rarer in Scotland than we thought - they haven't turned up in any of our NARRS surveys [there]," said Dr Wilkinson.

Common lizards, thought to occur throughout the UK, were seen rarely in the north and central regions, including Wales. Slow-worms were also found to be scarce in these areas.

Dr Wilkinson believes that this may be because these leg-less lizards are more difficult to find, as they burrow in undergrowth. So a reduced number of sightings may not necessarily reflect a decrease in their population

Surprisingly, palmate newt numbers are higher than expected, which might indicate changes in the quality of Britain's ponds.

Unlike many other amphibian species, these small newts thrive in acidic pools that are formed through acid rain fall or agricultural run-off.

The main drive of amphibian and reptile decline is thought to be habitat fragmentation and development.

Conservationists say this is a particular problem for toads, which are more sensitive than frogs to changes in habitat.

The final NARRS report is due to be published in Spring 2014.

Tuesday, March 15, 2011

The Coastal Tailed Frog Discovered in the Gracia River Forest


Ascaphus truei. Photo Credit: Mokele
Members of the genus, Ascaphus (family Ascaphidae)  are commonly called the tailed frogs, with the name referring to the extension of the male cloaca which is used as a copulatory organ. The "tail" is a unique characteristic of the two species in the genus and is an adaptation for internal fertilization for the two species that inhabit fast-flowing streams. Peter Fimrite of the San Francisco Chronicle has written an article on the discover of the Ascaphus truei in Mendicino County's Garcia River Forest. The presence of the frog in the Garcia River is significant because it signals the success of the forest restoration work that has been going on in the Garcia River drainage. Find the entire article here.

Monday, March 14, 2011

Pythons & Birds in the Everglades

You knew this was coming. The following press describes the research documenting the damage invasive pythons are doing to bird populations in Everglades National Park.

Scientists find that non-native snakes are taking a toll on native birds

Python bivittatus. JCM
The Everglades National Park in Florida is home to hundreds of species of native wildlife. It has also become the well-established home of the non-native Burmese python—known to be a predator of native species. Now scientists, for the first time, have conducted a detailed analysis of the avian component of the python's diet and the negative impact the snakes may have on Florida's native birds, including some endangered species.

The Burmese python (Python molurus bivittatus), native to Southeast Asia, was first recorded in the Everglades in 1979—thought to be escaped or discarded pets. Their numbers have since grown, with an estimated breeding population in Florida in the tens of thousands. As researchers investigate the impact of this snake in the Everglades, scientists from the Smithsonian Institution, South Florida Natural Resources Center and the University of Florida examined the snake's predation of the area's birds. They found that birds, including endangered species, accounted for 25 percent of the python's diet in the Everglades.

"These invasive Burmese pythons are particularly hazardous to native bird populations in North America because the birds didn't evolve with this large reptile as a predator," said Carla Dove, ornithologist at the Smithsonian's Feather Identification Lab in the National Museum of Natural History. "Conversely, the python is able to thrive here partly because it has no natural predator to keep its numbers in check."

The scientists collected 343 Burmese pythons in Everglades National Park as part of their study between 2003 and 2008. Eighty-five of these snakes had bird remains in their intestinal tract. From these remains the team identified 25 species of birds by comparing feathers and bone fragments with specimens in the Smithsonian's collection. The results reflected a wide variety of species, from the 5-inch-long house wren to the 4-foot-long great blue heron. Four of the species identified (snowy egret, little blue heron, white ibis and limpkin) are listed as "species of special concern" by the Florida Fish and Wildlife Conservation Commission. The team also identified the remains of a wood stork, which is a federally endangered species.

"These pythons can also inhabit a wide variety of habitats, so their impact is not restricted to just the native species within the Everglades," Dove said. "The python's high reproductive rate, longevity, ability to consume large prey and consumption of bird species are causes for serious conservation and control measures."

Dove, C. J., R. W. Snow, M. R. Rochford, F. J. Mazzotti. Birds Consumed by the Invasive Burmese Python (Python molurus bivittatus) in Everglades National Park, Florida, USA. The Wilson Journal of Ornithology, 2011; 123 (1): 126 DOI: 10.1676/10-092.1

Diabetes, Venom & the Conservation of Biodiversity


In the next 15 years it is estimated that 380 million people world wide will be diagnosed with diabetes. Obesity and the accompanying resistance to insulin result in the progressive failure of b-cells to produce type 2 diabetes. The chronic complications of diabetes comprise an increased risk of death and disability from coronary heart disease, stroke and peripheral vascular disease, and microvascular disease, resulting in retinopathy, nephropathy and neuropathy. Diabetes is the major medical cause of blindness in developed countries, as well as a major cause of end-stage renal failure. Thus there is a major research effort to find new and effective therapies for diabetes. Byetta, a synthetic exenatide, was approved in 2005 as the first in class of a new molecules for treating Type 2 Diabetes. US sales peaked at $678 million in 2008. The development of Byetta resulted from two lines of investigation, these being the development of the ‘incretin concept’ and a parallel, at first unrelated, study of the venom of the American, the Gila Monster, Heloderma suspectum.The venom contained a molecule identified as exendin-4, a peptide mimicking the incretin hormone glucagon-like peptide 1 (GLP-1). The  ‘incretin concept’ hypothesis proposed that hormones from the gut contributed to the insulin secretion in response to meals, led to the identification of glucagon-like peptide 1 (GLP-1) as an important ‘incretin’ hormone. GLP-1 not only increases insulin secretion but increases b-cell proliferation and survival, while suppressing glucagon secretion, it also delays gastric emptying and suppresses appetite, all of these actions contributing to a potential anti-diabetic effect. However, GLP-1 has a very short half, it is rapidly broken down by dipeptidyl peptidase IV and ectopeptidases. A systematic investigation of the composition and activity of venom from the Gila monster,  led to the isolation of a 39-amino acid peptide, designated exendin-4, showing 53% structural homology with GLP-1. Exendin-4 mimicked GLP-1 through stimulating the GLP-1 receptor. Exendin-4 is not broken down as easily ad GLP-1 and this led to its experimental and clinical evaluation as an anti-diabetic. There is no better argument for the conservation of biodiversity when it comes to arguing with greedy corporations, than stories like this.

Citation
Furman, B.L. 2011. The development of Byetta (exenatide) from the venom of the Gila monster as an anti-diabetic agent. Toxicon, In Press, doi:10.1016/j.toxicon.2010.12.016

Sunday, March 13, 2011

Venom Composition in a Litter of Death Adders


Photo Credit: 

Mohammad Al-Saleh
Knowledge of venoms is incomplete and sometimes experiments produce conflicting results. At least one study suggested that juvenile venom was more toxic than adult venom, giving rise to the commonly held, but misleading, belief that neonates snakes were more poisonous than the adults. The primary functions of venom are immobilization of prey, initiation of digestion, and to deter potential predators. Thus, venom has evolved numerous  proteins with different roles to produce substantial variation in venom composition between genera and species as well as within species. Remarkably venom can vary within a single litter and even within an individual over its life time.Genetics determine venom composition but variation during the life of an individuals suggest plasticity in the expression of the venom genes. The metabolism of a snake increases after venom has been spent. In a new study Anna Pintor and colleagues examine the dependence of increases in metabolic rate following venom expenditure on the stage of venom replenishment that the venom producing tissue is in at the time of venom extraction in the Common Death Adder, Acanthophis antarcticus. They found that venom expenditure is followed by a sudden increase in metabolic rate when snakes have previously not expended venom for at least two days, suggesting that repetitive venom expenditure does not further increase the activity of venom gland tissue during this initial time period but that a second upregulation occurs when the tissue is past the initial activation stage. In addition, venom composition appears to remain constant during replenishment within an individual, but they observed  substantial variations between siblings. Thus, venom composition does not appear to change during replenishment in individuals of the Death Adder, A. antarcticus, but variation between individuals is surprisingly high. The authors suggest that venom components are most likely replenished at a similar rate with metabolic costs being related to slow and extended rates of synthesis. They report an apparent absence of additional increases in metabolism after venom expenditure during the early stages of replenishment and suggest the physiological response to venom expenditure is not additive, but is initiated only while the venom glands are past a certain stage of replenishment. The mechanism that activates venom gland tissue is not known and further research in this direction would be of interest. Also see this related post.

Citation
Pintor A. F., K. L.Winter, A. K. Krockenberger, and J. E. Seymour. 2011. Venom physiology and composition in a litter of Death Adders (Acanthophis antarcticus) and their parents. Toxicon 57:68-75.

Saturday, March 12, 2011

Musk Turtles & Their Habitat


Common Musk Turtle, Stenotherous odoratus
Musk turtles, Sternotherous odoratus (family Kinosternidae), are highly aquatic and are  rarely observed basking on branches or shorelines (ariel basking) which is typical of most freshwater turtles. Instead, musk turtles bask while floating at the surface of the water under or in aquatic vegetation. Gabriel Picard and colleagues expected aquatic habitats with surface cover of emergent aquatic vegetation such as lily pads or other  floating macrophytes to be of higher thermal quality than other aquatic habitats devoid of such cover. They examined musk turtles preferentially use of these high thermal quality habitats in the St. Lawrence River (Ontario, Canada). The study area was along the southeastern shore of Grenadier Island. The turtles were captured by hand and 22 adult musk turtles were fitted with temperaturesensitive radio-transmitters. They found habitats with the highest thermal quality were the ones with surface cover, such as lily pads, followed by shallow water. As expected, musk turtles used habitats non-randomly and had a strong preference for thermally superior habitats. This is consistent with the typical aquatic basking behaviour observed in musk turtles, suggesting that there is a strong link between thermal quality of habitats and habitat selection, even in this almost entirely aquatic turtle. The authors note the importance of protecting natural shoreline habitats because they possess more emergent and aquatic vegetation than developed shorelines, a habitat structure that is crucial to musk turtles.


Picard, G., M.-A. Carrière, G. Blouin-Demers. 2011. Common Musk Turtles (Sternotherus odoratus) select habitats of high thermal quality at the northern extreme of their range. Amphibia-Reptilia 32 (2011): 83-92.

Friday, March 11, 2011

A New Snake From Indonesia

Boiga jaspidea, Borneo
An estimated 400 species of known snakes occur in Indonesia and this number has remained relatively stable during the past few decades, because little work has been done in this collection of islands and very few herpetologists are working in Indonesia. This situation has changed. The genus Boiga (sometimes called cat snakes) contains 32 to 35 species depending upon who is doing the counting. The genus is widely distributed in Southeast Asia and composed of mostly medium to large-sized snakes that feed on birds and small mammals. Boiga. dendrophila (sometimes called the Mangrove Snake) has numerous but distinctive subspecies, a rare case for Southeast Asian herpetofauna and it is unclear if this is a widespread species or a complex of species. Widespread species are relatively uncommon in Southeast Asia because of the regions complex geological history that has imposed and removed barriers to gene flow over time. Gilang Ramadham and colleagues have discovered a snake similar in morphology to Boiga cynodon (Boie, 1827). However, It differs from cynodon in several ways, it is only half of the size of B. cynodon , has a higher number of dorsal scales, a lower number of ventral and subcaudals and has a very fine postorbital stripe. The new snake, Boiga hoeseli inhabits the Nusa Tenggara Islands of Indonesia and the type locality is Flores. The new snake is named after J. K. P. van Hoesel author of the first guide book to Java snakes.

Citation
Ramadhan, Gilang; Djoko T. Iskandar and Dadang R. Subasri. 2010. New Species of Cat Snake (Serpentes: Colubridae) Morphologically Similar to Boiga cynodon from the Nusa Tenggara Islands, Indonesia. Asian Herpetological Research 1 (1): 22-30.

Thursday, March 10, 2011

Plague Rats and Tiapans in Bedourie in Queensland

The Long-haired Rat or Plague Rat, Rattus villosissimus, is endemic to northern Australian where its populations sometimes reach plague proportions. It is larger than most other native rodents with a body length of 12-22 cm and 50-280 g in weight. The Plague Rat is usually uncommon, living in widely scattered populations in wet areas, restricted to refugia with favorable conditions. The Inland Taipan (Oxyuranus microlepidotus) has evolved its world renowned venom to immobilize and kill this rodent, and an explosion in the rat population will be quickly followed by increases in snakes and other orther predators. The population fluctuations are the result of increased rainfall. The following story is from the HeraldSun.com.au.

"The town of Bedourie in far western Queensland has been struck by a rat plague - and snakes looking for a feed are following them into town.

Queensland government agent in the town of 150, Rachel Farran, said the local rat population had boomed following good weather last year.

She said hundreds of thousands of rats were in town, eating their way through doors and walls, burrowing into Eskys and chewing electrical cords.

"The rats have been a complete nightmare," Ms Farran said.

"You go downstairs to put the washing on and you hear rats screaming in the yard.

"There's a massive amount of them in our chook pen, and they also go into the shed.

"They've actually made a track that goes from the chookpen to that shed.

"There's hole in the wall at the police barracks where they've chewed through. At the clinic they've had two doors they've chewed through."

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Ms Farran said some of the rats were 25cm long, excluding the tail.

Bedourie had almost 400mm of rain from March 5 to 7 which she hoped would have drowned many rats, but it has also driven snakes into town.

Ms Farran said she saw rats in plague proportions on a drive 200km south to Birdsville on Australia Day.

"There was no way you could have counted them. They were just in groups all over the road.

"There were thousands just in spots in the road."

Ms Farran said she had spotted a deadly western taipan and a two-metre brown snake in recent days.

Bedourie is flooded in, with the road north expected to open in about two weeks, Ms Farran said.

Another 40 foot Anaconda Story


Never let the absence of evidence stand in the way of a good story. Slate.com is carrying a series called World of Wonders, Part  5 written by Joshua Foer (posted Feb 17, 2011) is titled, On the trail of a 40-foot Anaconda, the fifth hidden wonder of South America. The story chronicles a trip on the Marañón and Samiria rivers, in the Pacaya-Samiria reserve in the Peruvian Amazon. The author and his companion consider the Pacaya prime anaconda country, because every local seems to have a story about the massive serpent that got away. Their guide, Juan Carlos claimed that his army unit once shot a 40-foot anaconda while on a commando mission deep in the Amazon. And of course the remains disappeared when the military brass took the snake and so record-breaking catch was never verified. (Where have we heard this before?) Juan Carlos is quoted as saying, "People have wasted a lot of money looking in the wrong places…” Besure to look at the photos accompanying this article, I particularly like the aerial photo of a riparian mud flat shaped like a snake's head.

For a different take on this and the classic stories of over-sized snakes go to my Giant Constricting Snakes Web Site.

Wednesday, March 9, 2011

On the Origin of St George Utah's Desert Tortoise Population and More Biodiversity vs the Economy

St. George, Utah has become known as "Utah's Dixie," its temperate climate with mild winters make it ideal or year-round golf and as a location for retirement communities, it is also a gateway to Zion National Park. Red Cliffs Desert Reserve is located in north of St George, in Washington County in a transition zone between three ecosystems: the Mojave Desert, the Great Basin, and the Colorado Plateau. The Reserve supports a unique flora and fauna with species from each of the regions, as well as endemics. Red Cliffs was originally created for the protection of the Desert Tortoise, Gopherus agassizii in 1996. The tortoise is listed as Threatened by the US Fish and Wildlife Service. However, the Reserve also protects habitat for other sensitive species.

Drew Allard, has now written a commentary for the Spectrum, a southwest Utah media outlet, questioning whether the Red Cliff’s tortoise population is worthy of protection. Allard suggests that the population is not native, and is the result of humans transporting the tortoises. He writes, 
“… early in the 20th century they were accidentally transported here from a department store on Utah Hill in the Beaver Dam Mountain range west of St. George. Dixie State College professor Glen Blakley said, "A free tortoise was given to people when they bought a bucket of water on Utah Hill to cool (their) overheated car. So by the time the people would get to St. George, the parents say to their kids, 'Put that thing out now.' This claim isn't denied or accepted by the Red Cliff Reserve’s Biologist Cameron Rognan, who acknowledges the story with a conceding grin. He admits that there are indications of tortoises from the Beaver Dam Mountain range getting a lift from humans, but he emphasizes that these hitchhikers were most likely additions to the already established St. George tortoise population. He suggests that the tortoises are probably native to both areas." 
The first reference to tortoises in Utah appears to be in Tanner (1927), when he refers to the presences of tortoises in a bird checklist for the Virginia River Valley of Utah. Angus Woodbury (1930) officially recorded the tortoise as part of the Utah fauna in 1930, And Woodbury and Ross Hardy (1948) started studying the Utah tortoise population in 1936. They marked 281 tortoises, 182 were recaptured a total of 812 times. Of interest is that found 17 specimens that showed signs of being in captivity, five specimens had holes drilled in their shells, probably so they could be tethered, two had initials carved in them. One bore the date 1932 and the initials “CR”, but by 1942 when the turtle had been recaptured, the initials had disappeared and the “1932 looked like “1132.” Thus, there is evidence that humans have been moving the Desert Tortoise around for a while. The straight line distance between The Beaver Dam Slope tortoise population and Red Cliffs is about 16 miles, but much of the distance is a mountain barrier that may have prevented the tortoises from colonizing the St. George area by itself. 

Allard cites an AP report that $96 million was spent in the U.S. on preserving desert tortoises between 1996 and 2006. And, notes that not only does the tortoise collect money, it prevents money from being made – the presence of the tortoise is blocking the construction of a solar energy complex that could generate billions of dollars for California's economy. However, the proposed site is located on BLM land― desert tortoise habitat.

As for southern Utah, Allard cites the Red Cliffs Reserve annual expense report showing the reserve has declining income, spending about $400,000 on all expenditures.. While in 2009 they spent $613,000; in 2008, they spent $805,000; and in 2007, they spent more than a million dollars. These amounts were Red Cliffs Reserve’s expenditures as a whole, not just for the tortoises. The Reserve is multi-purpose and used by hikers, bikers and rock climbers.

Thus the argument of the environment verses the economy continues. Some molecular work on the St, George tortoises could settle the problem of its origins. Unfortunately, it will not settle the issue of dollars vs conservation or dollars vs biodiversity.

Literature
Tanner, V. 1927. Notes on birds collected in the Virginia River Valley of Utah. The Condor, 29:196-200.

Woodbury, A. M. 1931. The reptiles of Utah. Bulletin of the University of Utah 21:1-129.

Woodbury, A. and R. Hardy. 1948. Studies of the Desert Tortoise, Gopherus agassizii. Ecological Monographs 18:145-200

Monday, March 7, 2011

Update on San Francisco's Sharp's Park and the California Red-legged Frog

Camden Swita, a reporter for the Menlo Park Patch is reporting that a group of environmental  organizations are suing San Francisco today over violations to the Environmental Species Act at Sharp Park Golf Course. 
A California Red-legged Frog egg 
mass at Sharp's Park that is drying out. 
Photo Credit Camden Swita.
The Wild Equity Institute had issued a 60-day intent to sue with the San Francisco Recreation and Parks Department (RPD), which manages the golf course, on Nov. 18, 2010, but nothing had been sent to a court until today. Joining  Wild Equity as plaintiffs are the Center for Biological Diversity, National Parks Conservation Association, Surfrider Foundation, Sequoia Audubon Society, and the Sierra Club.The plaintiffs' intentions in the suit are: to compel the RPD to adopt a complete habitat restoration agenda for Sharp Park west of Highway 1; second, to force the RPD to develop a habitat protection process for the land in accordance with ESA laws; and third, they want a cessation to endangered and threatened species deaths at Sharp Park. The plaintiffs' complain that currently the city and county of San Francisco are unlawfully killing frogs and snakes, and that damage has been done to these populations as recently as last week.


As recently as February 22, 2011, the Plaintiffs have discovered California red-legged frog egg masses exposed to the air due to the water management activities conducted by the City. Because these egg masses must stay moist to survive, egg masses exposed to the air quickly dry out, and all the frog eggs die. A single egg mass can contain thousands of eggs: thus, the loss of even one egg mass can result in significant mortality for the species. Follow this link to the whole story.

A New Fossil Helmeted Frog that Supports a Biogeographical Link Between South America and Australasia


The Chilean Helmeted Toad, Calyptocephalella gayi
Photo Credit José Grau de Puerto Montt
The southern part of South America east of the Andes has a dry, cool climate with open grasslands and a relatively poor frog fauna, with most of the living species present being leptodactylid frogs and their relatives. However, in the Paleogene the environment was warm and humid with a subtropical forest. Raul Gomez and colleagues have recovered fossils from an Eocene lake deposit that included anuran remains that represent pipoids and basal hyloids, frog lineages not represented in the living fauana. And, they have recently describe an articulated, hyperossified neobatrachian frog, Calyptocephalella pichileufensis (Calyptocephalellidae) from Rıo Pichileufi in northwestern Patagonia, Argentina. The fossil frog was found rocks dated at 47.46 MYA and the authors estimate the median annual temperature at this time was 19.2◦C. The new amphibian was estimated to have a body length of 110 mm. The authors note that Michael Tyler anticipated that frogs associated with the Australian myobatrachids should occur in the cool temperate austral fauna of South America in 1979. Decades later, the sister-group relationship of the endemic South American calyptocephalellids and Australian myobatrachids (clade Australobatrachia), was recovered in several molecular analyses. To date the oldest records of calyptocephalellids are from Patagonia, where they can be traced back to the Late Cretaceous. Today the family Calyptocephalellidae (Helmeted Water Frogs) is restricted to Chile and maybe Argentina and it host four species (Calyptocephalella gayi and three species of Telmatobufo). Telmatobufo inhabit fast-flowing streams in temperate Nothofagus forest while C. gayi lives more slow moving streams and lakes in the lowlands of Chile, up to 500 m in elevation.

Citation
Gómez, R. O., A. M. Báez and P. Muzzopappa. 2011. A new helmeted frog (Anura: Calyptocephalellidae) from an Eocene subtropical lake in northwestern Patagonia, Argentina. Journal of Vertebrate
Paleontology, 31:50-59

The Oldest Pteranodon?

The following is a press release from Southern Methodist University.

Fossilized bones discovered in Texas from a flying reptile that died 89 million years ago may be the earliest occurrence of the prehistoric creature known as Pteranodon.

Previously, Pteranodon bones have been found in Kansas, South Dakota and Wyoming in the Niobrara and Pierre geological formations. This likely Pteranodon specimen is the first of its kind found in Texas, according to paleontologist Timothy S. Myers at Southern Methodist University in Dallas, who identified the reptile. The specimen was discovered north of Dallas by an amateur fossil hunter who found various bones belonging to the left wing.

Pteranodon was a type of pterosaur that lived about the same time as some dinosaurs, about 100 million to 65 million years ago. The only reptiles to dominate the ancient skies, pterosaurs had broad leathery wings and slim torsos.

Adult pterosaur, toothless variety with about a 12-foot wing span
The specimen identified by Myers is an adult pterosaur of the toothless variety and while larger than most birds, wasn't among the largest pterosaurs, Myers said, noting it had a wing span between 12 and 13 feet, or 3.6 to 4 meters. It was discovered in the Austin Group, a prominent rock unit in Texas that was deposited around 89 million years ago, early in the geological time period called the Late Cretaceous.

Pterosaurs, many of which survived on fish, lived at a time when a massive ancient sea cut across the central United States. The Western Interior Seaway was a shallow body of water that split North America in half from the Arctic Ocean to the Gulf of Mexico.

More than a thousand Pteranodon fossils have been unearthed from the middle part of the seaway.

No definitive Pteranodon specimens have emerged from the southern part that is now Texas.

The SMU specimen, if it is Pteranodon, would be the first discovered so far south in the Western Interior Seaway, said Myers, a postdoctoral researcher in SMU's Huffington Department of Earth Sciences.

Myers reported and described the specimen in "Earliest Occurrence of the Pteranodontidae (Archosauria: Pterosauria) in North America; New Material from the Austin Group of Texas" in the Journal of Paleontology.

Left wing suggests Pteranodon; cause of death a mystery
Key to identifying the SMU fossils as Pteranodon is a humerus of 5.7 inches, or 14.5 centimeters. The humerus is the uppermost bone in the wing and attaches to the torso. The humerus of the SMU specimen, while complete, did suffer some damage during fossilization when it became compressed and distorted through millions of years of compaction.

"If it wasn't crushed so badly, it would be possible to determine if it really is Pteranodon," Myers said. "These bones are easily flattened. They are hollow inside, because they have to be lightweight to allow a pterosaur to fly. So they compress like a pancake as they're embedded in layers of rock."

While it's difficult to narrow the humerus definitively to a specific genus and species, some features clearly identify the specimen as part of the Pteranodontidae family, most likely the genus Pteranodon. It exhibits, for example, the prominent warped deltopectoral crest that is characteristic of members of the Pteranodontidae family, called pteranodontids, he said.

Discovered along with the humerus were parts of the elongated fourth finger that in pterosaurs forms the wing. The SMU specimen's metacarpal — at 20 centimeters — is incomplete, missing an estimated 37 percent of its length.

The fossils do not solve the mystery of the reptile's cause of death, Myers said. But it appears the animal probably died in flight over the sea and then fell into the water. Its carcass probably floated for some time, so that when the flesh decomposed the bones separated at the joints, known as "disarticulation," before they settled to the sea floor and were buried.

"We know it was disarticulated when it was buried because the bones weren't preserved in correct anatomical position," Myers said. "Abrupt truncation of the broken end of one of the bones and infilling of the break with sediment also indicates that the breakage and disarticulation took place prior to burial."

May be oldest Pteranodon in world
If the specimen represents Pteranodon, Myers said, it would be the oldest one in North America by 1 million to 2 million years, and the second oldest pteranodontid in the world.

Pterosaurs were alive from the Late Triassic — more than 200 million years ago — to the Late Cretaceous, evolving from small-bodied creatures to some of the largest animals to ever inhabit the skies, Myers said. An older pteranodontid specimen, belonging to the genus Ornithostoma, previously was identified in England.

"Any pterosaur material is fairly rare to find unless you have exceptional preservation conditions. They are frail, fragile bones, and they require rapid burial to be well preserved," Myers said. "The SMU specimen was deposited relatively far offshore in deep water, perhaps 50 to 80 feet deep. It's fairly exceptional because of the number of elements. Typically you'll only find one piece, or one part of a piece in the local rock."

During the Early Cretaceous, many types of pterosaurs lived around the world, Myers said. The earliest ones had thin, razor-sharp teeth. In the transition from Early to Late Cretaceous, the toothed variety disappear from the fossil record and toothless forms, like the SMU specimen, become more common, he said.

Dallas area specimens illustrate pterosaur evolution
North Texas is fortunate to have had both the toothed and toothless kinds discovered in the area, illustrating the evolutionary transition, noted Myers.

Besides the toothless specimen just identified by Myers, an older toothed pterosaur, Aetodactylus halli, previously was discovered in the Dallas area. Aetodactylus, also identified by Myers, lived 95 million years ago.

"This new specimen adds a lot more information about pterosaurs in North America," Myers said. "It helps constrain the timing of the transition from toothed to toothless because there's only a few million years separating this specimen and Aetodactylus."

Amateur fossil collector Gary Byrd of Rockwall, Texas, discovered the new SMU pterosaur fossils about 10 years ago. A roofing contractor who keeps an eye out for fossils, Byrd made the find after stopping to look at two freshly excavated culverts while driving through a new subdivision in Collin County. Using a hammer and pick he dug out the bones and brought them to SMU paleontologists Louis Jacobs and Dale Winkler. Jacobs and Winkler indicated the fossils were likely a pterosaur. Byrd donated the fossils to SMU's Shuler Museum of Paleontology.

"I found a couple parts of a fish, and then when I saw these my initial thought was that they weren't fish," Byrd recalled. "I kind of knew it was something different — a birdlike thing. It's very rare you find those thin, long bones."

This isn't the first time Byrd has hit it lucky finding fossils. In 1994 he discovered dinosaur bones that he donated to SMU's Shuler Museum. The specimen was identified as a rare primitive duck-billed dinosaur and named Protohadros byrdi after Byrd. — Margaret Allen

Citation:
Myers. T. S. 2010. Earliest Occurrence of the Pteranodontidae (Archosauria: Pterosauria) in North America: New Material from the Austin Group of Texas. Journal of Paleontology, 84 (6): 1071 DOI: 10.1666/09-082.1

Saturday, March 5, 2011

This Russell’s Viper Survived the Perils of Plastic


The Deccan Herald is carrying the following story.

This Russell’s viper survived the perils of plastic
Subhash Chandra N S Bangalore, March 5, DHNS
Reckless disposal of plastic waste almost proved fatal for a venomous Russell’s viper that was found struggling for life near Kengeri. Some passersby recently found the two-foot viper writhing in pain and alerted the People for Animals (PFA), a city-based organisation of animal rights activists.

A PFA volunteer, who rushed to the spot, said he found the viper gasping for breath. Dr Vetrivelu, attached to the PFA, said: “First we thought it was injured, but later, we found something stuck in its mouth.”

As Russell’s viper is venomous, it was sedated before close examination, he said. “We pulled out a piece of a polyethene bag stuck in its jaws. We used forceps and pulled out three more pieces of the polyethene bag that were not less than two feet,” the doctor said.

t took nearly three days for the snake to recover. Suffering from severe dehydration, the viper, weighing about 180 gm, was treated with ringers lactate and normal saline (to prevent dehydration) and ‘subcutane’ (to strengthen the vital organs) for about four days before releasing it into Turhalli forest.

Herpetologists “Snake” Shyam of Mysore and Gowri Shankar say sometimes snakes consume things bigger than their size.

“I once found a snake which had swallowed two metres of cloth,” said Shyam. Shankar said snakes tended to devour anything that smelt like rat or eggs.

Are We In The 6th Mass Extinction?

The following is a University of California press release.While the following study looks at mammals, it seems likely that similar situations exist with amphibians and reptiles.

Tigers are one of Earth's most critically endangered species. Extinction of the majority of such species would indicate that the sixth mass extinction is in our near future. With the steep decline in populations of many animal species, from frogs and fish to tigers, some scientists have warned that Earth is on the brink of a mass extinction like those that occurred only five times before during the past 540 million years.

Each of these ‘Big Five’ saw three-quarters or more of all animal species go extinct.

In a study published in the March 3 issue of the journal Nature, University of California, Berkeley, paleobiologists assess where mammals and other species stand today in terms of possible extinction, compared with the past 540 million years, and they find cause for hope as well as alarm.

“If you look only at the critically endangered mammals – those where the risk of extinction is at least 50 percent within three of their generations – and assume that their time will run out, and they will be extinct in 1,000 years, that puts us clearly outside any range of normal, and tells us that we are moving into the mass extinction realm,” said principal author Anthony D. Barnosky, UC Berkeley professor of integrative biology, a curator in the Museum of Paleontology and a research paleontologist in the Museum of Vertebrate Zoology.

“If currently threatened species – those officially classed as critically endangered, endangered and vulnerable – actually went extinct, and that rate of extinction continued, the sixth mass extinction could arrive within as little as 3 to 22 centuries,” he said.

Nevertheless, Barnosky added, it’s not too late to save these critically endangered mammals and other such species and stop short of the tipping point. That would require dealing with a perfect storm of threats, including habitat fragmentation, invasive species, disease and global warming,

“So far, only 1 to 2 percent of all species have gone extinct in the groups we can look at clearly, so by those numbers, it looks like we are not far down the road to extinction. We still have a lot of Earth’s biota to save,” Barnosky said. “It’s very important to devote resources and legislation toward species conservation if we don’t want to be the species whose activity caused a mass extinction.”

Coauthor Charles Marshall, UC Berkeley professor of integrative biology and director of the campus’s Museum of Paleontology, emphasized that the small number of recorded extinctions to date does not mean we are not in a crisis.

“Just because the magnitude is low compared to the biggest mass extinctions we’ve seen in a half a billion years doesn’t mean to say that they aren’t significant,” he said. “Even though the magnitude is fairly low, present rates are higher than during most past mass extinctions.”

“The modern global mass extinction is a largely unaddressed hazard of climate change and human activities,” said H. Richard Lane, program director in the National Science Foundation’s Division of Earth Sciences, which funded the research. “Its continued progression, as this paper shows, could result in unforeseen – and irreversible – negative consequences to the environment and to humanity.”

The study originated in a graduate seminar Barnosky organized in 2009 to bring biologists and paleontologists together in an attempt to compare the extinction rate seen in the fossil record with today’s extinction record. These are “like comparing apples and oranges,” Barnosky said. For one thing, the fossil record goes back 3.5 billion years, while the historical record goes back only a few thousand years. In addition, the fossil record has many holes, making it is impossible to count every species that evolved and subsequently disappeared, which probably amounts to 99 percent of all species that have ever existed. A different set of data problems complicates counting modern extinctions.

Dating of the fossil record also is not very precise, Marshall said.

“If we find a mass extinction, we have great difficulty determining whether it was a bad weekend or it occurred over a decade or 10,000 years,” he said. “But without the fossil record, we really have no scale to measure the significance of the impact we are having.”

To get around this limitation, Marshall said, “This paper, instead of calculating a single death rate, estimates the range of plausible rates for the mass extinctions from the fossil record and then compares these rates to where we are now.”

Barnosky’s team chose mammals as a starting point because they are well studied today and are well represented in the fossil record going back some 65 million years. Biologists estimate that within the past 500 years, at least 80 mammal species have gone extinct out of a starting total of 5,570 species.

The team’s estimate for the average extinction rate for mammals is less than two extinctions every million years, far lower than the current extinction rate for mammals.

“It looks like modern extinction rates resemble mass extinction rates, even after setting a high bar for defining ‘mass extinction,’” Barnosky said.

After looking at the list of threatened species maintained by the International Union for Conservation of Nature (IUCN), the team concluded that if all mammals now listed as “critically endangered,” “endangered” and “threatened” go extinct, whether that takes several hundred years or 1,000 years, Earth will be in a true mass extinction.

“Obviously there are caveats,” Barnosky said. “What we know is based on observations from just a very few twigs plucked from the enormous number of branches that make up the tree of life.”

He urges similar studies of groups other than mammals in order to confirm the findings, as well as action to combat the loss of animal and plant species.

“Our findings highlight how essential it is to save critically endangered, endangered and vulnerable species,” Barnosky added. “With them, Earth’s biodiversity remains in pretty good shape compared to the long-term biodiversity baseline. If most of them die, even if their disappearance is stretched out over the next 1,000 years, the sixth mass extinction will have arrived.”

Citation
Barnosky, A. D., N. Matzke, S. Tomiya, G. O. U. Wogan, B. Swartz, T. B. Quental, C. Marshall, J. L. McGuire, E. L. Lindsey, K. C. Maguire, et al. Has the Earth’s sixth mass extinction already arrived? Nature, 471, 51-57. DOI: 10.1038/nature09678