Friday, 9 May 2014

Diverse gene pool critical for tigers' survival, say experts

New research by Stanford scholars shows that increasing genetic diversity among the 3,000 or so tigers left on the planet is the key to their survival as a species.

Iconic symbols of power and beauty, wild tigers may roam only in stories someday soon. Their historical range has been reduced by more than 90 percent. But conservation plans that focus only on increasing numbers and preserving distinct subspecies ignore genetic diversity, according to the study. In fact, under that approach, the tiger could vanish entirely.
"Numbers don't tell the entire story," said study co-author Elizabeth Hadly, the Paul S. and Billie Achilles Professor in Environmental Biology at Stanford and senior fellow at the Stanford Woods Institute for the Environment. She is a co-author of the study, which was published April 17 in the Journal of Heredity.
That research shows that the more gene flow there is among tiger populations, the more genetic diversity is maintained and the higher the chances of species survival become. In fact, it might be possible to maintain tiger populations that preserve about 90 percent of genetic diversity.
Rachael Bay, a graduate student in biology at Stanford's Hopkins Marine Station and the lead author of the study, said, "Genetic diversity is the basis for adaptation."
Loss of diversity
The research focused on the Indian subcontinent, home to about 65 percent of the world's wild tigers. The scientists found that as populations become more fragmented and the pools of each tiger subspecies shrink, so does genetic diversity. This loss of diversity can lead to lower reproduction rates, faster spread of disease and more cardiac defects, among other problems.
The researchers used a novel framework, based on a method previously employed to analyze ancient DNA samples, to predict what population size would be necessary to maintain current genetic diversity of tigers into the future. The authors believe this new approach could help in managing populations of other threatened species.
The results showed that for tiger populations to maintain their current genetic diversity 150 years from now, the tiger population would have to expand to about 98,000 individuals if gene flow across species were delayed 25 years. By comparison, the population would need to grow to about 60,000 if gene flow were achieved immediately.
Neither of these numbers is realistic, considering the limited size of protected tiger habitat and availability of prey, among other factors, according to the researchers.
Limited habitat
"Since genetic variability is the raw material for future evolution, our results suggest that without interbreeding subpopulations of tigers, the genetic future for tigers is not viable," said co-author Uma Ramakrishnan, a former Stanford postdoctoral scholar in biology and current researcher at the National Centre for Biological Sciences in Bangalore, India.
Because migration and interbreeding among subspecies appear to be "much more important" for maintaining genetic diversity than increasing population numbers, the researchers recommend focusing conservation efforts on creating ways for tigers to travel longer distances, such as wildlife corridors, and potentially crossbreeding wild and captive tiger subspecies.
"This is very much counter to the ideas that many managers and countries have now - that tigers in zoos are almost useless and that interbreeding tigers from multiple countries is akin to genetic pollution," said Hadly. "In this case, survival of the species matters more than does survival of the exclusive traits of individual populations."
Understanding these factors can help decision-makers better address how development affects populations of tigers and other animals, the study noted.
Conservation efforts for other top predators have shown the importance of considering genetic diversity and connectivity among populations, according to the report. One example is Florida panthers: since individuals from a closely related panther subspecies were introduced to the population, Florida panthers have seen a modest rise in numbers and fewer cases of genetic disorders and poor fitness.

Extinct kitten-sized hunter discovered

Western Reserve University student and his mentor have discovered an ancient kitten-sized predator that lived in Bolivia about 13 million years ago -- one of the smallest species reported in the extinct order Sparassodonta.

Third-year undergraduate student Russell Engelman and Case Western Reserve anatomy professor Darin Croft made the finding by analyzing a partial skull that had been in a University of Florida collection more than three decades.
The researchers report their finding in the Journal of Vertebrate Paleontology.
"The animal would have been about the size of a marten, a catlike weasel found in the Northeastern United States and Canada, and probably filled the same ecological niche," said Engelman, an evolutionary biology major from Russell Township, Ohio.
The researchers refrained from naming the new species mainly because the specimen lacks well-preserved teeth, which are the only parts preserved in many of its close relatives.
The skull, which would have been a little less than 3 inches long if complete, shows the animal had a very short snout. A socket, or alveolus, in the upper jaw shows it had large, canines, that were round in cross-section much like those of a meat-eating marsupial, called the spotted-tailed quoll, found in Australia today, the researchers said.
Although sparassodonts are more closely related to modern opossums than cats and dogs, the group included saber-toothed species that fed on large prey. This small Bolivian species probably fed on the ancient relatives of today's guinea pigs and spiny rats, the researchers said.
"Most predators don't go after animals of equal size, but these features indicate this small predator was a formidable hunter," Croft said.
The specimen had not been studied in detail after being collected. It was provisionally identified as belonging to a particular group of extinct meat-eating opossums, due in part to its small size. Further adding to the identity challenge, almost all small sparassodonts have been identified by their teeth and lower jaws, which this skull lacks.
Croft wanted to study the skull because its age is nearly twice that of the oldest known species of meat-eating opossum. The specimen was found in a mountainous site known as Quebrada Honda, Bolivia, in 1978, in rock layers dated 12 million to 13 million years ago.
Structurally, extinct meat-eating opossums and sparassodont skulls share a number of similarities due to their similar meat-eating diet, Engelman said.
"No single feature found in the skull was so distinctive that we could say one way or the other what it was," Croft said, "but the combination of features is unique and says this is a sparassodont."
One key was that a particular bone of the orbit, the boney socket of the eye, does not touch the nasal bone in an opossum but does in a sparassodont.
The short snout was a kind of red herring. While jaguar-sized sparassodonts had them, the smaller members of the order had fox-like faces. And this species was smaller than most of those.
These smaller sparassodonts also have gaps between their teeth that are absent in most larger species. The skull shows no gaps.
Overall, the animal's features are a mixture of those found in different species of sparassodonts, but are not characteristic of in any one subgroup within the order. That puts this species near the bottom of the family tree, the researchers said.
Croft, who regularly collects from the same site where the skull was found, will return there this summer to gather evidence he hopes will show whether this species lived in an open grassland, forest or mixed habitat.
He also hopes to find the lower jaw, which may enable direct comparisons with known species and provide enough foundation to name the animal.


Thursday, 8 May 2014

Deepwater Horizon disaster could have billion dollar impact

The Deepwater Horizon oil spill in the Gulf of Mexico in April 2010 will have a large economic impact on the U.S. Gulf fisheries. A new study published in the Canadian Journal of Fisheries and Aquatic Sciences(CJFAS) says that over 7 years this oil spill could have a $US8.7 billion impact on the economy of the Gulf of Mexico. This includes losses in revenue, profit, and wages, and close to 22 000 jobs could be lost.

The Deepwater Horizon oil spill in the Gulf of Mexico in April 2010 will have a large economic impact on the U.S. Gulf fisheries.
"Unlike the visually obvious and immediate effects on birds and mammals, the effects of oil on fisheries can be more difficult to detect, though they are no less devastating," says lead author U. Rashid Sumaila. "Oil and hydrocarbons are taken up by plankton and other surface-dwelling species that link to aquatic food chains." This in turn affects the fishing industry.
The Deepwater Horizon, a British Petroleum oil rig, exploded in the Gulf of Mexico on 20 April 2010. By August 2010 it was estimated that it had leaked an estimated 4.9 million barrels of oil (780 million L), making it the largest accidental marine oil spill in US waters. In comparison, the Exxon Valdez oil spill in 1989 amounted to less than 0.5 million barrels. This study estimates the economic impact this spill will have on commercial and recreational fisheries and mariculture in the Gulf of Mexico.

Almost seven million birds perish at communication towers in North America each year

Every year nearly 7 million birds die as they migrate from the United States and Canada to Central and South America, according to a new USC study published on April 25 in the journal PLoS ONE.

The birds are killed by the 84,000 communication towers that dot North America and can rise nearly 2,000 feet into the sky, according to the authors of "An Estimate of Avian Mortality at Communication Towers in the United States and Canada."
Placing that figure in context, the Exxon Valdez oil spill killed 250,000 birds and the Empire State building is 1,250 feet high.
"This is a tragedy that does not have to be," said lead author Travis Longcore, associate professor in the USC Spatial Sciences Institute at the USC Dornsife College of Letters, Arts and Sciences.
The taller the tower the greater the threat, the study found. The 1,000 or so towers above 900 feet accounted for only 1.6 percent of the total number of towers. Yet these skyscraper towers killed 70 percent of the birds, about 4.5 million a year, Longcore said.
Most of the birds spent winter in places like the Bahamas and summer in Canada. With names like the Common Yellowthroat and the Tennessee Warbler, they could fit in the palm of one's hand.
"These birds eat insects and keep our forests healthy," Longcore said. "They are quite beautiful. We have a long history of appreciating birds. Millions of people watch birds."
However, the birds are not generally killed by running into the tower itself but the dozens of cables, known as guy wires, that prop up the thin, freestanding structure, Longcore said.
During bad weather, the birds were pushed down by cloud cover and flew at lower altitudes. The clouds also removed navigation cues, such as stars, leaving only the blinking or static red lights of towers.
The blinking did not fool the birds, but towers with a static red light resulted in more dead birds.
Estimated annual avian mortality from communication towers by Bird Conservation Region. High mortality estimates in Peninsular Florida and Southeastern Coastal Plain reflect the more numerous and taller communication towers in these regions.
"In the presence of the solid red lights, the birds are unable to get out of their spell," Longcore said. "They circle the tower and run into the big cables holding it up."
Longcore estimated that changing the steady-burning lights on the 4,500 towers greater than 490 feet tall (about 6 percent of the total) could reduce mortality about 45 percent, or about 2.5 million birds. The study also recommended that businesses share towers to reduce their number and build more freestanding towers to reduce the need for guy wires.
In 2005, Longcore and his colleagues started collecting and analyzing data from field studies that counted the number of bird kills at communication towers across the United States. The team only used findings that documented bird kills for at least a year and in some cases for several decades.
The numbers were scrutinized to find the average bird mortality based on height, the guy wires and the types of lights affixed to the tower.
The team then matched up tower types, sizes and attributes of 38 tower studies, applying those findings to the 84,000 towers across Canada and the United States in preparation for the new publication, which also was submitted to the Federal Communications Commission.
"One of the things this country has been great about is saying we care about not losing species on our watch," Longcore said. "With these towers, we are killing birds in an unnatural way. This is senseless."
The study, which does not include shorter towers that typically are used for mobile telephone transmission, focused on towers taller than 180 feet, which typically provide TV and radio frequencies.
The study's authors included Catherine Rich and Beau MacDonald of The Urban Wildlands Group, Pierre Mineau, Daniel G. Bert and Erin Mutrie of Environment Canada, Lauren M. Sullivan of UCLA, Sidney A. Gauthreaux of Clemson University, Michael Avery of the U.S. Department of Agriculture/Wildlife Services, Albert M. Manville of U.S. Fish and Wildlife Service, Emilie Travis and David Drake of the University of Wisconsin and independent scholar Robert L. Crawford.
The study was funded in part by The Urban Wildlands Group, Environment Canada, the American Bird Conservancy and Defenders of Wildlife.

$200 bird scaring line for trawlers can cut albatross deaths by over 90 percent

The sight of seabirds following trawlers in order to feast from discarded fish is a common maritime sight, but each year many thousands of seabirds are killed by overhanging cables or in nets. New research inAnimal Conservation assesses mortality figures from South Africa to show that a simple bird scaring line can reduce the mortality rate by over 90%

The research compiled data from five years of observations to compare current and historic mortality rates. Previous research shows that in 2006 approximately 18,000 seabirds were killed each year by the South African hake trawl fishery, of which 14,000 were albatrosses.
By reviewing data over five years the team could assess the impact of bird scaring lines, streamers costing $200 that hang from a line attached to the stern of a fishing vessel. The results show that bird scaring lines alone resulted in 73 to 95% lower mortality in the winter, including a 95% reduction in albatross deaths.
Albatrosses are the most threatened group of birds on earth, with fishery-related deaths being the biggest threat to this group. Due to the many months they spend at sea at a time, Albatrosses produce few off-spring, meaning that these deaths have a disproportionately damaging impact on the global population.

DOES THE DIRE WOLF CARE FOR EACH OTHER IN THE PACK?

From the remaining of the dire wolf what we found in the La Brea Tar Pit we found some of the broken dire wolf bones. These injuries most probably happened when these animals were out for hunting. In one case the researcher found that the upper hand arm bone of the dire wolf is broken, and this injury may makes that dire wolf a three legged animal. In another case the scientist found that one eye of the dire wolf was completely smashed. That dire wolf may be left one eyed after that injury. Now in the first case, from the study of the remaining it is found that that species lived at least 5 to 6 months more after that injury. In the second case, we found that that dire wolf lived several years after that injury. But here a huge question arises – in the both cases, the dire wolf surely lost their capability of hunting a large prey. So they cannot hunt by their own. Then how those dire wolves lived so long time after that injury? The probability of getting dead animal flesh every time is very much low.  This makes many scientists to believe that may be in the pack, the dire wolf care for each other,
Again in many dire wolves bone remaining we found the bite marks of none but the other dire wolves. So, it’s confirm that they dire wolf fight with each other.
That is why some scientists also thing that the dire wolf hunt in packs but they do not care for each other. And they also believe that in the broken dire wolf remains, the injuries are not that fatal that they cannot hunt by themselves. And more over the fighting between the dire wolves proves that the dire wolf do not care for each other. They just hunt in packs but no caring for each other, just like their gray wolf cousin.

Now I’m going to say what I believe in this case and explain why I believe this.

According to my study and imagination, I believe the dire wolves do care for each other in the pack.  I’ve seen that broken bones in a documentary called ‘Prehistoric Predator- episode 1-Dire Wolf’ in Net Geo Wild. I believe – those injuries are not that fatal that they cannot hunt. But as we know, the world was not same as of today. And the prey species of the dire wolves are normally the larger prey. And with those injuries those dire wolves just cannot hunt the larger prey alone. Now, because of their injury, they cannot hunt with the packs. One weak wolf in the time of hunting gave the prey a huge advantage to save himself.
Now, if we believe the fact that the dire wolf pack does not care for each other, then the injured dire wolf is not needed in the pack. They became a single wolf, and have to hunt alone. With that injury they cannot hunt larger prey. Now we concentrate to the smaller preys and the carcass what they can get. Every prey has its own way to save itself. Most of the smaller preys are either very much fast runner or a perfect Camouflage. So for a one eyed dire wolf or a three legged dire wolf it looks almost impossible to hunt those animals. And on the case of carcass, here, they can be able to find that, but you see, 10000 years ago the North America is a nightmare for everybody, there are many big deadly predators like sabre-tooth cat, short-faced bear and many more. So, finding the carcass for several years regularly and feed that completely without any other predator’s attention is impossible. More over most probably the North American lands are just like today’s African lands where a predator killed another to secure their foods and the future of their own siblings. So other predators will kill that single wolf at the first sight. This proves that the injured dire wolf continued with the pack and since the lived a long live after the injury that confirms the other wolves in their packs share their food with the injured ones.

Remaining of dire wolves found in the La Brea Tar Pit
For the bite marks of the dire wolves in the other dire wolves bone may be because of this – u see, in the La Brea Tar Pit we found 3500 individual dire wolf remaining –  Much larger than other any other predator. This leads us to the fact that the dire wolves dominated that area. Now, it’s not possible that there is only one pack that rules that area. Because if that happened then there is no other predator remains that place. The huge dire wolf pack finished all other predators. But that does not happened. So there are many packs controlling the North America. Very much likely they often involved in brutal fights between themselves. Again in the packs, there may be sometimes fights occurs to dominate the pack. These are may be the cause of the injuries of the dire wolves happened by other dire wolves.

Fish rain down on Sri Lanka village

Villagers in west Sri Lanka have said they have been surprised and delighted by an unusual rainfall of small fish.
The edible fish fell during a storm and are believed to have been lifted out of a river during a strong wind.
Villagers in the district of Chilaw said they heard something heavy falling and found scores of fish with a total weight of 50kg (110lbs).
It is not the first such incident in Sri Lanka - in 2012, a case of "prawn rain" was recorded in the south.
Scientists say that "fish rain" usually occurs when swirling whirlwinds over relatively shallow water develops into waterspouts and sucks in almost anything in the water including fish, eels and even frogs.
The marine life can be carried long distances by buffeting clouds even when the waterspout stops spinning.
Villagers say that the "fish rain shower" took place on Monday with the creatures falling on the village green, roads and roofs.
Some of the fish - each three to five inches (5cm-8cm) in length - were still alive and were put in a buckets of water by villagers who ate them later.
This is the third time this has happened in Sri Lanka, but not from the same area.
In addition to the reported "prawn rain" of 2012 in the south, there was yellow and red "meteor rain" the same year - a weather development that is reportedly still being investigated by US and British scientists.
Fish is a valued commodity in Sri Lanka.
Villagers in the Chilaw district of Sri Lanka collect fish that fell in the rainVillagers collected the contents of the "fish shower" into buckets and enjoyed an unusual free meal

Natural hybridization produced dolphin species

newly published study on the clymene dolphin, a small and sleek marine mammal living in the Atlantic Ocean, shows that this species arose through natural hybridization between two closely related dolphins species, according to authors from the Wildlife Conservation Society, the American Museum of Natural History's Sackler Institute for Comparative Genomics, the University of Lisbon, and other contributing groups.

In a molecular analysis including the closely related spinner and striped dolphins, scientists conclude that the clymene dolphin is the product of natural hybridization, a process that is more common for plants, fishes, and birds, but quite rare in mammals.
The study appears in the online journal PLOS ONE. The authors include: Ana R. Amaral of the University of Lisbon, Portugal, and the American Museum of Natural History; Gretchen Lovewell of the Mote Marine Laboratory; Maria Manuela Coelho of the University of Lisbon; George Amato of the American Museum of Natural History; and Howard Rosenbaum of the Wildlife Conservation Society and American Museum of Natural History.
"Our study represents the first such documented instance of a marine mammal species originating through the hybridization of two other species," said Ana R. Amaral, lead author of the study and research associate at the American Museum of Natural History. "This also provides us with an excellent opportunity to better understand the mechanisms of evolution."
The classification of the clymene dolphin has been a longstanding challenge to taxonomists, who initially considered it to be a subspecies of the spinner dolphin. Then in 1981, thorough morphological analyses established it as a recognized distinct species. In the current study, researchers sought to clarify outstanding questions about the dolphin's origin and relationships with rigorous genetic analyses.
"With its similar physical appearance to the most closely related species, our genetic results now provide the key insights into this species origin" said Dr. Howard Rosenbaum, Director for WCS's Ocean Giants Program and a senior author on the study. "Very little is known about the clymene dolphin, whose scientific name translated from Greek is oceanid, but ironically also can mean fame or notoriety. Hopefully, our work will help draw greater attention to these dolphins in large parts of their range."
Based on research conducted at the American Museum of Natural History's Sackler Institute for Comparative Genomics, the authors examined the nuclear and mitochondrial DNA from skin samples obtained from both free-ranging dolphins by means of biopsy darts and deceased dolphins obtained through stranding events. Using samples from 72 individual dolphins (both clymene dolphins and the closely related spinner and striped dolphins), the researchers amplified one mitochondrial DNA marker and six nuclear DNA markers as a means of analyzing the evolutionary relationship between the clymene dolphin and its closest relatives.
The level of discordance among the nuclear and mitochondrial markers from the three species, the authors assert, is best explained as an instance of natural hybridization. Specifically, the team discovered that while the mitochondrial genome of the clymene dolphin most resembled the striped dolphin, the nuclear genome revealed a closer relation to the spinner dolphin. The authors also noted that continued hybridization may still occur, although at low levels.
The clymene dolphin grows up to nearly seven feet in length and inhabits the tropical and temperate waters of the Atlantic Ocean. Threats to the species include incidental capture as bycatch in fishing nets, which in some parts of the range has turned into direct hunts for either human consumption or shark bait.
The authors thank NOAA Fisheries for funding to initiate this project.

New Tyrannosaur named 'Pinocchio rex'

Pinocchio was smaller than T. rex but its nose was a third longer - perhaps for a different hunting strategy
A new type of Tyrannosaur with a very long nose has been nicknamed "Pinocchio rex".
The ferocious carnivore, nine metres long with a distinctive horny snout, was a cousin of Tyrannosaurus rex.
Its skeleton was dug up in a Chinese construction site and identified by scientists at Edinburgh University, UK.
The 66-million-year-old predator, officially named Qianzhousaurus sinensis.
"Pinocchio" looked very different to other tyrannosaurs.
"It had the familiar toothy grin of T. rex, but its snout was long and slender, with a row of horns on top," said Edinburgh's Dr Steve Brusatte.
"It might have looked a little comical, but it would have been as deadly as any other tyrannosaur, and maybe even a little faster and stealthier.
"We thought it needed a nickname, and the long snout made us think of Pinocchio's long nose."
Researchers now think several different tyrannosaurs lived and hunted alongside each other in Asia during the late Cretaceous Period, the last days of the dinosaurs.
Skull of Qianzhousaurus
The enormous Tarbosaurus (up to 13m) had deep and powerful jaws likeT. rex - strong enough to crush the bones of giant herbivores.
The thinner teeth and lighter skeleton of Qianzhousaurus suggest it hunted smaller creatures, such as lizards and feathered dinosaurs. But at nine metres tall and weighing almost a tonne, it was still a gigantic carnivore.
"You wouldn't want to run into either of these guys," said Dr Brusatte.
'Weird features'
Pinocchio's snout was 35% longer than other dinosaurs of its size. So, why the long face?
"The truth is we don't know yet. But it must've been doing something different," Dr Brusatte told BBC News.
"The iconic picture of a tyrannosaur is T. Rex, the biggest, baddest dinosaur of all.
"But this new species was lighter, less muscular. It breaks the mould. Perhaps it had a faster bite and hunted in a different way."
Prof Junchang Lu and Dr Steve Brusatte at construction site where dinosaur fossil discoveredProf Junchang Lu and Dr Steve Brusatte at the discovery site
The discovery of "Pinocchio" settles an argument over a series of strange new fossil finds.
In recent years, two tyrannosaurs with unusually prominent proboscises were dug up in Mongolia, and named Alioramus.
The horny-snouted predators appeared to come from an entirely new branch of the tyrannosaur family.

"The trouble was, they were both juveniles. So it was possible their long snouts were just a weird transient feature that grows out in adults," said Dr Brusatte, an expert in tyrannosaur evolution.
But this new Qianzhousaurus specimen is an almost fully mature adult. It was found largely intact and remarkably well preserved by road construction workers near Ganzhou in southern China.
"It's twice the size of the juveniles, and yet it still shows the same features - including the distinctive horns," said Dr Brusatte.
"This is the slam dunk we needed: the long-snouted tyrannosaurs were real."
Palaeontologists are now confident that Qianzhousaurus and Alioramusare part of a new subgroup of tyrannosaurs with elongated skulls.
Their discovery from Mongolia to southern China suggests these "second tier" carnivores were widely distributed, according to Prof Junchang Lu of the Chinese Academy of Geological Sciences, a co-author on the paper.
"Although we are only starting to learn about them, the long-snouted tyrannosaurs were apparently one of the main groups of predatory dinosaurs in Asia," he said.
With these "weird" creatures now accepted as being part of a whole family, more and more of their long-snouted relatives are expected to be unearthed.
As for the riddle of Pinocchio's nose, the scientists hope to solve it via biomechanical studies of its jaw - which may hint at its feeding habits.

New species of dolphin found in Australian waters

A species of humpback dolphin previously unknown to science is swimming in the waters off northern Australia, according to a team of researchers working for the Wildlife Conservation Society, the American Museum of Natural History, and numerous other groups that contributed to the study.

To determine the number of distinct species in the family of humpback dolphins (animals named for a peculiar hump just below the dorsal fin), the research team examined the evolutionary history of this family of marine mammals using both physical features and genetic data. While the Atlantic humpback dolphin is a recognized species, this work provides the best evidence to date to split the Indo-Pacific humpback dolphin into three species, one of which is completely new to science.
"Based on the findings of our combined morphological and genetic analyses, we can suggest that the humpback dolphin genus includes at least four member species," said Dr. Martin Mendez, Assistant Director of WCS's Latin America and the Caribbean Program and lead author of the study. "This discovery helps our understanding of the evolutionary history of this group and informs conservation policies to help safeguard each of the species."
The authors propose recognition of at least four species in the humpback dolphin family: the Atlantic humpback dolphin (Sousa teuszii), which occurs in the eastern Atlantic off West Africa; the Indo-Pacific humpback dolphin (Sousa plumbea), which ranges from the central to the western Indian Ocean; another species of Indo-Pacific humpback dolphin (Sousa chinensis), which inhabits the eastern Indian and western Pacific Oceans; and a fourth Sousaspecies found off northern Australia yet to be named (the formal adjustment of the naming and number of species occurs through a separate and complementary process based on these findings).
"New information about distinct species across the entire range of humpback dolphins will increase the number of recognized species, and provides the needed scientific evidence for management decisions aimed at protecting their unique genetic diversity and associated important habitats," said Dr. Howard Rosenbaum, Director of WCS's Ocean Giants Program and senior author on the paper.
A new as-of-yet unnamed species of humpback dolphin is shown off the coast of northern Australia.
Working to bring taxonomic clarity to a widespread yet poorly known group of dolphins, the authors assembled a large collection of physical data gathered mostly from beached dolphins and museum specimens. Specifically, the team examined features from 180 skulls covering most of the distribution area of the group in order to compare morphological characters across this region.
The researchers also collected 235 tissue samples from animals in the same areas, stretching from the eastern Atlantic to the western Pacific Oceans, analyzing both mitochondrial and nuclear DNA for significant variations between populations.
The humpback dolphin grows up to 8 feet in length and ranges from dark gray to pink and/or white in color. The species generally inhabits coastal waters, deltas, estuaries, and occurs throughout the Indian and Pacific oceans to the coasts of Australia. The Atlantic humpback dolphin is considered "Vulnerable" according to the IUCN Red List, whereas the Indo-Pacific dolphin species Sousa chinensis is listed as "Near Threatened." Humpback dolphins are threatened by habitat loss and fishing activity.

Scots pine marten recovery spreads south

A new report has shown pine martens are starting to re-colonise the south of Scotland after being absent from most of the area for nearly 200 years.The Scottish Natural Heritage (SNH) study, with The Vincent Wildlife Trust (VWT), found them in three areas.The new sites are south and west of Glasgow, the Upper Tweed Valley and Annandale and Eskdalemuir.VWT survey coordinator Lizzie Croose described the discovery of the rare animals as "significant".Pine martens were once found throughout the UK, but suffered a dramatic decline in the 19th century due to woodland clearance, trapping for fur, and predator control by gamekeepers.In the last half of the 20th century, however, populations recovered in Scotland and are now established in most areas north of the Central Belt, including the northern fringes of Glasgow and some other parts of the Central Belt.
Pine martens have been found to have re-colonised three sites in southern Scotland
The species is still rare in the UK and absent from most of England and Wales.
In 1988, the species was given full legal protection.
Now it has been discovered at the three new sites in southern Scotland after a lengthy absence.
A small number of pine martens were re-introduced to the Galloway Forest in the early 1980s, but the new arrivals are not thought to have spread from this group - which has remained in isolation.
These new groups of pine martens have most likely originated from "a combination of natural spread and deliberate releases".
The information on the pine martens in new areas comes from a recent survey, in which pine marten droppings were collected from woodlands and subjected to DNA analysis to confirm their origin.
Records of pine martens were also collected from foresters, naturalists and local record centres.
A small number of pine martens were re-introduced to the Galloway Forest in the early 1980s
Ms Croose said: "The pine marten is the first mammalian predator which almost became extinct in the 19th century to make a substantial recovery in Scotland.
"Pine martens have been absent from most of southern Scotland for almost 200 years so their return is significant."
Rob Raynor, SNH's mammal advisory officer, said that it was "quite likely" they would re-colonise most suitable habitats in southern Scotland in time.
"At present, re-colonisation of the new areas is still at an early stage, but if breeding populations do establish successfully, pine martens will probably expand throughout southern Scotland and south into northern England," he said.

Dolphin whistle warnings: Remotely monitoring acoustical changes in dolphin whistles may be powerful new tool for conservation

team of researchers in Italy, Portugal, Spain, France, Britain and the United States has demonstrated that remotely monitoring the acoustical structures of dolphin vocalizations can effectively detect "evolutionarily significant units" of the mammal -- distinct populations that may be tracked for prioritizing and planning conservation efforts.

Two dolphins.
This finding, presented at the 167th meeting of the Acoustical Society of America, to be held May 5-9, 2014, in Providence, Rhode Island, suggests that placing remote acoustical monitoring platforms on ocean buoys and the like may be a viable, low-cost and automated way of monitoring populations of dolphins and rapidly alerting ecologists to the threats that confront them.
"Acoustical changes can be used for constant and continuous monitoring of population belonging to endangered species," said Elena Papale of the University of Torino, who led the research. "We found that [by remotely monitoring dolphin whistles], it is possible to distinguish between evolutionary significant units."
The discovery emerged from a large, multinational collaboration that pulled together data from five research groups based in Italy, Portugal, Spain, Britain and France. Those groups were already monitoring dolphins for a number of existing scientific studies. Other groups in the United States collaborated by providing sound analysis equipment. Shepherding all these groups of people and the flood of data they produced was a challenge, Papale said, but the greater challenge was working out how to distinguish the flood of whistles from one group of dolphins from another.
Animal vocalizations have acoustic characteristics that reflect an organism's genes, its adaptation to ecological conditions and the interactions between their genes and the environment. The differences between groups of dolphins within the same species may be slight and hard to detect however, because morphological features, ecological conditions and socio-behavioral aspects of the creatures influence the structure of whistle. The problem is also a dynamic one, since vocalizations may vary in short time scale.
So at the start of the research, it was not clear whether acoustical analyses alone would be able to tease apart the common threads for given groups of dolphins and differentiate between them.
Papale and her colleagues compared 123 sightings of three dolphin species from the Atlantic Ocean and the Mediterranean Sea (Stenella coeruleoalba, Delphinus delphis and Tursiops truncatus). They analyzed whistles from 49 hours of audio recordings made at the same time as the sightings and tested whether they could definitively identify dolphin populations by analyzing the acoustical parameters of the whistles.
This allowed them to correctly assign more that 82 percent of data to the correct dolphin population, based solely on the acoustic structure, a proof of principle that the acoustic structure of whistles can be used to monitor recent or rapid changes in the local population biology.
"More work is still needed to develop an automatic system for population recognition," Papale said. She added that other research groups are focusing on the development of software but for the moment only for species-specific identification, not intra-specific recognition.

Wednesday, 7 May 2014

Super-sized muscle made twin-horned dinosaur a speedster

A meat-eating dinosaur that terrorized its plant-eating neighbours in South America was a lot deadlier than first thought, a University of Alberta researcher has found. Carnotaurus was a seven-metre-long predator with a huge tail muscle that U of A paleontology graduate student Scott Persons says made it one of the fastest running hunters of its time.

Carnotaurus, a seven-meter-long eating machine, had a huge tail muscle that University of Alberta paleontology graduate student Scott Persons says made it one of the fastest running hunters of its time.
A close examination of the tail bones of Carnotaurusshowed its caudofemoralis muscle had a tendon that attached to its upper leg bones. Flexing this muscle pulled the legs backwards and gave Carnotaurus more power and speed in every step.
In earlier research, Persons found a similar tail-muscle and leg-power combination in the iconic predatorTyrannosaurus rex. Up until Persons published that paper, many dinosaur researchers thought T. rex's huge tail might have simply served as a teeter-totter-like counterweight to its huge, heavy head.
Persons' examination of the tail of Carnotaurus showed that along its length were pairs of tall rib-like bones that interlocked with the next pair in line. Using 3-D computer models, Persons recreated the tail muscles of Carnotaurus. He found that the unusual tail ribs supported a huge caudofemoralis muscle. The interlocked bone structure along the dinosaur's tail did present one drawback: the tail was rigid, making it difficult for the hunter to make quick, fluid turns. Persons says that what Carnotaurus gave up in maneuverability, it made up for in straight ahead speed. For its size, Carnotaurus had the largest caudofemoralis muscle of any known animal, living or extinct.

Dinosaur shook tail feathers for mating show

University of Alberta researcher's examination of fossilized dinosaur tail bones has led to a breakthrough finding: some feathered dinosaurs used tail plumage to attract mates, much like modern-day peacocks and turkeys.

U of A Paleontology researcher Scott Persons followed a chain of fossil evidence that started with a peculiar fusing together of vertebrae at the tip of the tail of four different species of dinosaurs, some separated in time and evolution by 45 million years.
Persons says the final vertebrae in the tails of a group of dinosaurs called oviraptors were fused together forming a ridged, blade-like structure. "The structure is called a pygostyle" says Persons. "Among modern animals only birds have them."
Researchers say fossils of Similicaudiptery, an early oviraptor, reveal feathers radiating from the fused bones at the tail tip. Similicaudiptery was not known to be a flying dinosaur and Persons contends its tail feathers evolved as a means of waving its feathered tail fans.
No direct fossil evidence of feathers has been found with the fossils of the oviraptors that followedSimilicaudiptery, but Persons says there is still strong evidence they had a feathered tail.
Persons reasons that because the later oviraptor had the same tail structure as the feathered Similicaudipteryx, the tails of later oviraptors' still served the same purpose, waving feathered tail fans.
Persons says the hypothesis of oviraptor tail waving is supported by both the bone and muscle structure of the tail.
Individual vertebrae at the base of an oviraptor's tail were short and numerous, indicating great flexibility. Based on dissections of modern reptile and bird tails, Persons reconstruction of the dinosaur's tail muscles revealed oviraptors had what it took to really shake their tail feathers.
Large muscles extended far down the tail and had a sufficient number of broad connection points to the vertebrae to propel oviraptor's tail feathers vigorously from side to side and up and down.
Oviraptors were two-legged dinosaurs that had already gone through major diversifications from the iconic, meat eating dinosaur family. Oviraptors were plant eaters that roamed parts of China, Mongolia, and Alberta during the Cretaceous period, the final age of the dinosaur.
"By this time a variety of dinosaurs used feathers for flight and insulation from the cold, "said Persons. "This shows that by the Late Cretaceous dinosaurs were doing everything with feathers that modern birds do now," said Persons.
In addition to feathered-tail waving, oviraptors also had prominent bone crests on their head, which Persons says the dinosaur also may have used in mating displays.
"Between the crested head and feathered-tail shaking, oviraptors had a propensity for visual exhibitionism," said Persons.

Fossils of first feathered dinosaurs from North America discovered: Clues on early wing uses

The ostrich-like dinosaurs in the original Jurassic Park movie were portrayed as a herd of scaly, fleet-footed animals being chased by a ferocious Tyrannosaurus rex. New research published in the journalScience reveals this depiction of these bird-mimic dinosaurs is not entirely accurate -- the ornithomimids, as they are scientifically known, should have had feathers and wings.

The new study, led by paleontologists Darla Zelenitsky from the University of Calgary and François Therrien from the Royal Tyrrell Museum of Palaeontology, describes the first ornithomimid specimens preserved with feathers, recovered from 75 million-year-old rocks in the badlands of Alberta, Canada.
This is an artistic reconstruction of feathered ornithomimid dinosaurs found in Alberta
"This is a really exciting discovery as it represents the first feathered dinosaur specimens found in the Western Hemisphere," says Zelenitsky, assistant professor at the University of Calgary and lead author of the study. "Furthermore, despite the many ornithomimid skeletons known, these specimens are also the first to reveal that ornithomimids were covered in feathers, like several other groups of theropod dinosaurs."
The researchers found evidence of feathers preserved with a juvenile and two adults skeletons ofOrnithomimus, a dinosaur that belongs to the group known as ornithomimids. This discovery suggests that all ornithomimid dinosaurs would have had feathers.
The specimens reveal an interesting pattern of change in feathery plumage during the life of Ornithomimus. "This dinosaur was covered in down-like feathers throughout life, but only older individuals developed larger feathers on the arms, forming wing-like structures," says Zelenitsky. "This pattern differs from that seen in birds, where the wings generally develop very young, soon after hatching."
This discovery of early wings in dinosaurs too big to fly indicates the initial use of these structures was not for flight.
"The fact that wing-like forelimbs developed in more mature individuals suggests they were used only later in life, perhaps associated with reproductive behaviors like display or egg brooding," says Therrien, curator at the Royal Tyrrell Museum and co-author of the study.
Until now feathered dinosaur skeletons had been recovered almost exclusively from fine-grained rocks in China and Germany. "It was previously thought that feathered dinosaurs could only fossilize in muddy sediment deposited in quiet waters, such as the bottom of lakes and lagoons," says Therrien. "But the discovery of these ornithomimids in sandstone shows that feathered dinosaurs can also be preserved in rocks deposited by ancient flowing rivers."
Because sandstone is the type of rock that most commonly preserves dinosaur skeletons, the Canadian discoveries reveal great new potential for the recovery of feathered dinosaurs worldwide.
The fossils will be on display this fall at the Royal Tyrrell Museum in Drumheller, Alberta.