Thursday, 23 February 2017

Cars and chlamydia killing Queensland koalas

Date: February 21, 2017
Source: University of Queensland

Being hit by cars and chlamydia were the top causes of a dramatic rise in south-east Queensland koala deaths over the past two decades, according to a new University of Queensland-led study.

UQ School of Veterinary Science's Associate Professor Rachel Allavena and Dr Joerg Henning worked with the Queensland Government's Moggill Koala Hospital to analyse data about koala disease and death from 1997 to 2013.

"It's important data collected over the span of the koala population crash," Dr Allavena said.

"Populations throughout 'Koala Coast' declined by about 80 per cent over this period, so this iconic and famous species is in real trouble in our area."

The senior researchers and PhD student Viviana Gonzalez-Astudillo, determined that at least a quarter of the koalas hit by cars were otherwise in good health, meaning it was healthy, breeding animals that were killed.

About half of the population that died over the study period was affected by more than one disease or health problem, including trauma.

Chlamydia was particularly devastating for koalas, because of the potential to render females infertile and cause bladder and eye problems, making predator avoidance and food foraging harder.

Animal attacks, particularly from dogs, and wasting away from starvation, disease and poor teeth were other prominent causes of koala deaths.

continued 

Prey: The Reason Turtles First Came Out of Their Shells – via Herp Digest




By  NICHOLAS ST. FLEUR FEB. 17, 2017, New York Times

If you are reading this hunched over your desk or smartphone, take this moment to loosen up your neck. Move it up and down. Now side to side. Roll it around clockwise and counterclockwise. Now retract it into your shell. Oh wait, you can’t do that — you are not a turtle. But have you ever wondered how these reptiles evolved to have such an interesting trick?

Scientists have, and now after studying the cervical bones of a 150-million-year-old turtle fossil, a team of researchers thinks that most turtles developed the ability first as a way to spring their head forward quickly to snatch prey, rather than as a means of protection, as was previously thought. The ability further evolved in some turtles to become a crucial part of their defenses. The researchers published their study Thursday in the journal 

The earliest known turtle ancestors were unable to retract their necks, but today’s modern species can. To understand turtle necks, however, you must first understand the two main types of turtles: cryptodires and pleurodires. 

Cryptodires include tortoises as well as most turtles: box turtles, sea turtles and alligator snapping turtles. They retract their necks straight back into their shells by folding the muscles vertically. Pleurodires include species that are mostly found in South America, Australia and Africa, like the matamata and snake-neck turtles. They bend their muscles horizontally to pull their necks back to the side and tuck it next to their shoulder.

Jérémy Anquetin, a paleontologist from the Jurassica Museum in Switzerland and the lead author, and his colleagues studied a 150-million-year-old turtle fossil that had some strange characteristics. The turtle, known as Platychelys oberndorferi, was from the Late Jurassic period and lived in what is today Germany and Switzerland. From its shell and skeleton the team could clearly tell that it belonged to the pleurodira group. But the shape of its two cervical bones suggested that it pulled its neck back vertically as cryptodires do, not horizontally. The neck also appeared to be unable to fully fold into the shell.

The neck retraction mechanism used by Platychelys oberndorferi and modern-day cryptodires to pull their heads straight back.

“Why did it have this neck retraction mechanism? This turtle is very peculiar,” Dr. Anquetin said. “Our fossil cannot retract it completely. It brings no value for protection, so we had to find an explanation for that.

The team homed in on the creature’s other features for clues. Its appearance was similar to modern bottom-dwelling turtles, suggesting that it was an ambush predator like the matamata turtle or the common snapping turtle. The two modern species are distantly related, but they hunt using similar tactics. They both lurk among the plants that shroud the floors of ponds, swamps and shallow lakes. Once an unsuspecting fish gets close enough, they strike.

“We can expect that our turtle was behaving the same way,” Dr. Anquetin said. He and his team report that the neck mechanisms seen in their extinct turtle and in modern-day cryptodires is an example of convergent evolution, meaning that both P. oberndorferi and present-day cryptodires evolved the ability independently of each other because of the evolutionary advantages that it offered them in their environments. The method of retracting their necks straight back allowed them to rapidly shoot out their heads and catch darting prey more easily.








Lemur facial recognition tool developed


21 February 2017


A team of researchers has developed a facial recognition system that can identify individual lemurs in the wild with high levels of accuracy.

The plan is to use the technology to help radically improve the way the endangered species is tracked.

LemurFaceID proved 97% accurate when comparing the faces of two different lemurs.

The animals were named the world's most endangered group of mammals in 2012.

The system was developed by a team of lemur experts and computer scientists.

The researchers have published a paper detailing their work in the journal BMC Zoology.

Co-author Rachel Jacobs, a biological anthropologist from George Washington University, said: "The ability to consistently study individuals over long periods of time, as well as integrate data across different studies, are some of the challenges we face when studying wild animal populations.

"Senior author Stacey Tecot, (University of Arizona), and I weren't particularly satisfied with the common approaches used in lemur research, so we aimed to do something different with red-bellied lemurs, and we sought the expertise of our computer science collaborators."

Previous efforts to track wild lemurs usually required researchers to trap and individually tag the animals.
 

Meet the frog that can sit on a thumbnail



By Helen Briggs BBC News


21 February 2017
 



Four new frogs so tiny that they can sit on a thumbnail have been discovered in the forests of India.

Among the smallest frogs in the world, they live on the forest floor and make insect-like calls at night.

Three larger species were also found, bringing to seven the number of night frogs discovered in the Western Ghats.

The mountain range, which runs parallel to the western coast of India, is home to hundreds of threatened plants and animals.

Scientists discovered the new species after several years of exploration in the forests of Kerala and Tamil Nadu.
 
 Secretive habits
"These tiny frogs can sit comfortably on a coin or a thumbnail," said Sonali Garg of the University of Delhi, who was among the team that found the new creatures.

"We were surprised to find that the miniature forms are in fact locally abundant and fairly common.
Night frig
 
Image copyright SD Biju

"They were probably overlooked by researchers because of their extremely small size, secretive habitats and insect-like calls."
 
 

Study examines life history of imperiled rattlesnake-Scientists show how climate, geography impact Eastern Massasauga – via Herp Digest




NORTHERN ILLINOIS UNIVERSITY, Press Release 2/16/17

A new study is bringing attention to a little known and imperiled rattlesnake that slithers among the wetlands in regions surrounding the Great Lakes.

The Eastern Massasauga rattler was once common in such states as Indiana and Illinois. Until recent years, it could still be found in Chicago's Cook County. But the reptile's range and numbers have been steadily declining. In 2016, the snake was listed as threatened under the U.S. Endangered Species Act.

In the new study, Northern Illinois University biological sciences professor Richard King and his former student Eric Hileman examine the life history of the Eastern Massasauga, revealing important local climate impacts on the snake that should be carefully weighed when developing conservation strategies.

"Our results provide evidence that climatic variation in the Great Lakes region strongly influences body size, individual growth rates and key aspects of reproduction," says Hileman, first author of the study published in PLOS ONE, a journal of the Public Library of Science. Hileman earned his Ph.D. in biological sciences from NIU in December and is now a postdoctoral fellow in biology at Trent University in Ontario, Canada.

Hileman, King and more than 40 co-authors gathered and synthesized more than a century of data on the snakes from study sites across the range of the Eastern Massasauga. Most of the data was culled from studies conducted from the mid-1990s forward at sites in Illinois, Indiana, Wisconsin, Michigan, Iowa, Ohio, Pennsylvania and New York, as well as Ontario, Canada.

The scientists found strong evidence for geographic variation in six of nine life-history variables. Among the findings:

                       The average body size of the snake and the size of its offspring increased with increasing mean annual precipitation, possibly because wetter climates yield greater prey abundance. 

                       Litter sizes decreased with increasing mean temperature, and increased by one offspring for each 1.89-degree increase in latitude, even when maternal size was held constant.

"It's been rare to look within a species and show that these patterns exist," King says. "The study results demonstrate that a one-size-fits all conservation strategy is not appropriate. Rather, assessments of extinction risk and the design of management strategies need to account for geography.”

The Eastern Massasauga snakes are generally found in wet prairies or sedge meadows, where the reptiles employ a sit-and-wait strategy to catch and feed on small mammals. Adult size ranges from about 2 feet to 2 ½ feet in length. While venomous, the snakes are not particularly aggressive or dangerous to work with.

"You're not likely to encounter them unless you're looking for them," King says. "It's easy to walk right by one. They're very cryptically colored to look like dead leaves and cattails, so they blend in exceedingly well."
The reptiles suffered habitat loss from extensive drainage of land for agriculture and development. As recently as the 1970s, some states had bounties on the snake.

With concerns over whether they would persist in the wild, the remaining snakes in Chicago's Cook County were taken into a captive breeding program in 2010, King says.

"In Illinois, they've nearly blinked out entirely," he adds. "We're probably down to one location in the southern part of the state that has a stable population. They seem to have stronger holds in Michigan and southern Ontario.”

The study authors believe findings will aid Eastern Massasauga recovery efforts.

"The life-history parameter estimates will be essential for improving models related to extinction risk and climate change," Hileman says. "The results from these predictive models can subsequently be used to develop site-specific management strategies."
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