New species of skink discovered in Australia

One of eight new reptiles and two frogs discovered in Western Australia last year

February 2012: A newly described skink species is going on display to the public in Perth, Australia.

NEW SPECIES: The Western Pilbara spiny tail skink

Picture: G. Gaikhorst

The Western Pilbara spiny-tail skink was just one discovery in what has been a busy time for WA Museum's reptile expert Dr Paul Doughty who has described eight new reptiles and two frog species in the past 12 months.

This year Dr Doughty's research has focussed on WA's Pilbara region which is one of the most diverse areas for reptiles in the world.

‘Western Australia is a great place to be a reptile and frog enthusiast, as it is incredibly diverse and we still are making exciting new discoveries like these spiny skinks and geckos every year,' said Dr Doughty.

'It's super-cute and friendly'Dr Doughty clearly has a passion for reptiles, describing the newly described Western Pilbara spiny-tail skink as ‘super-cute and friendly'.

'The Western Pilbara Spiny-Tail Skink is one of the most interesting species described this year. It has a rich red colouration to match the rocks of the Pilbara and has short-strong spines for protection from predators,' Dr Doughty said.

The description this year of the two species of spiny-tail skinks and the Pilbara barking gecko relied on new discoveries of populations from the Pilbara region, which has been the focus of floral and faunal surveys through new mining and developmental proposals and a Pilbara Biodiversity Survey by the Department of Environment and Conservation.

Genetic analyses provided by Professor Steve Donnellan of the South Australian Museum were key to revealing the new species of spiny-tail skinks.

‘Using DNA testing we are able to discover and learn so much more about Western Australia's biodiversity and gain insight into the evolution and history of our species,' Dr Doughty said.

http://www.wildlifeextra.com/go/news/skink-new.html

Personality Predicts Success of Invasive Species (Via Herp Digest)

Personality Predicts Success of Invasive Species
Wynne Parry, LiveScience Senior Writer
Date: 08 November 2011 Time: 07:01 PM ET

For invasive species, personality matters, according to new research that explores the question why some animals travel to, survive and take over in foreign habitats.

Humans have spread invasive species - starlings, lionfish, Asian carp and fire ants, to name a few -around the world to new habitats, where they can cause trouble for us and for native species.

A team of three Australian scientists observed two related lizards, one of which has successfully established itself as an invasive overseas, and found the invader had traits, such as a willingness to explore, that seemed to explain its success abroad. They also suggest that species whose members show a range of individual variation in their behavior - in other words, animals with more personality - may have a better shot at becoming invasives.

"Personality and behavioral traits are an important and, to date, unexplored component of the success of these species' invasions," said Bob Wong, a researcher from Monash University in Australia and an author of two recent studies on the subject. [Alien Invaders: Destructive Invasive Species]

Making an invasive

A lot of things have to go just right for an invasive species to be born.

"Not only do animals need to be in the right place at the right time in order to be inadvertently transported by humans, but they also need to be able to survive the often harsh and lengthy journey inside consignments of freight," said study researcher David Chapple, also from Monash University.

"When they arrive at the new destination, the stowaways have to contend with being strangers in a strange land and successfully adapt to new environments. In the face of these challenges, the new colonists must also thrive and reproduce before spreading out across the landscape," Chapple said.

Skink story

Chapple, Wong and Sarah Simmonds studied the delicate skink, which is the only Australian lizard species to have become an invasive species overseas, including in the Hawaiian Islands and New Zealand. They also looked at the similar garden skink, which has not established itself outside Australia.

After testing and observing the lizards' behaviors in the laboratory, the researchers concluded that the delicate skinks were more adventurous than their garden counterparts, showing more of an inclination to explore their environment. The delicate skinks were also more prone to hide when they found shelter.

This combination may make delicate skinks more likely to sneak into cargo, freight or other human belongings. Once inside, they are more likely to stay hidden, evading border checks and temperature changes that could prove fatal, according to the researchers writing in an article published online Oct. 18 in the journal Ecology and Evolution.

It's important to note that behavioral inclinations alone do not an invasive species make; for example, a hitchhiking species must arrive in a suitable habitat where it
can find food it eats.

The importance of personality

While behavioral differences between the two skinks were clear, not all delicate skinks showed themselves to be brave explorers in the lab - evidence of variation among individual animals, otherwise known as personality. As a result, if a group of skinks was given the opportunity to become invaders, only some would likely be successful, the researchers write.

While most attempts to identify behaviors associated with invasive success have focused on species-level traits, some research indicates that variation within a species may enhance its invasion potential, the same team of researchers writes in a separate study, published online Oct. 14 in the journal Trends in Ecology & Evolution.

"As we encroach farther and farther into the natural environment, animals have had more opportunities to jump on board our various transports. Given this increase, and the potential impact on biodiversity, it's important that we understand this phenomenon better," Wong said.

Physics of Burrowing Sandfish Revealed (via Herp Digest)

Physics of Burrowing Sandfish Revealed
Simulations show how lizard wriggles a fine line to maximize thrust, extension
By Daniel Strain, 2/22/11

The sandfish lizard wriggles through desert sands like a sci-fi monster. Now, using computer simulations and bendy robots, researchers at Georgia Tech in Atlanta have taken the most complete look yet at the everyday physics of burrowing animals.

And, boy, does this reptile wriggle, the team reports online February 23 in the Journal of the Royal Society Interface. "This particular behavior is built for speed," says physicist Daniel Goldman, one of the study coauthors.



Like the deadly sandworms in the Dune science fiction series, a host of animals from scorpions to snakes haunt subterranean deserts across the planet. It's not easy to study how these creatures careen through their environments, Goldman says. Scientists have a good idea how water behaves in the wake of an undulating eel or how air flows over a bird wing. But shuffling sand grains ping off each other like a wickedly complicated game of pool.



X-ray studies have shown that sandfish lizards (Scincus scincus) navigate such chaos with an earthwormlike wriggle, Goldman says, tucking in their legs and curling from side to side in S-shaped waves. A fast sandfish lizard dive covers two body lengths per second - and the creatures can grow to 4 inches long, he adds. But just how the lizards achieve such speed in a complex sandy environment wasn't clear. For that, Goldman's team turned to a new set of tools. 

First, researchers simulated sandfish lizards swimming through a field of 3-millimeter-wide glass beads on a computer. The program - which ate up 20 to 30 desktop PCs and still took days to run - illustrated how every bead bumped and thudded as the virtual lizard passed by. The real fun came next. The team built a spandex-covered robo-reptile that could wriggle much like the real thing. "The beauty of robotics compared to the simulation and theory: It's all in the real world," Goldman says. I!
f the team wanted the robot to bend more or less, the researchers just asked it to bend more or less.



On-screen or clad in spandex, the tests agreed. If virtual lizards curl too much, they don't move far enough forward with each wriggle. If they bend too little, the lizards can't give enough push. Real-life sandfish lizards walk, or wriggle, this fine line nearly perfectly. "They dive into the sand as fast as they can," Goldman says.

Such finely tuned diving isn't useful just for lizards, says Robin Murphy, director of the Center for Robot-Assisted Search and Rescue at Texas A&M University in College Station. She designs robots to help in the aftermath of disasters like earthquakes or mudslides. But when it comes to machines that can dig like earthworms and slip through rubble, nothing like that exists, she says.

"There's a lack of any technology short of a shovel." Burrowing animals could inspire new machines, but so far, few studies have been able to capture the constraints robots would face in dirt-filled or muddy environments. "This is the first I've seen that I said, 'Okay, we've got it,'" she says. 

Robots inspired by animals are neat, admits Eric Tytell, a researcher at Johns Hopkins University who studies how fish swim in water.

But the Georgia team flipped that inspiration around, too. Goldman and his colleagues used robots to get a better grasp of biology. And that's really clever, Tytell says. 

Goldman says his studies have convinced him that sandfish lizards dive for one reason - to escape. In the desert, there's nowhere else to hide. "You just want to get the hell out of there as fast as you can," he says.

Warm weather sets lowland skink sex

SNOW skinks can base their gender on either genes or temperature. Which strategy they choose appears to depend on the weather.


Ido Pen of the University of Groningen in the Netherlands and colleagues studied two clans of snow skinks, Niveoscincus greeni, living at low or high altitude in the mountains of Tasmania, Australia. The team captured pregnant skinks from each clan and allowed half of each group to lie in the sun for 10 hours per day, while the others were restricted to 4 hours. When the skinks gave birth, the scientists sexed their offspring.

Litters born to the lowland clan had a greater proportion of females after long days in the sun, compared to short days. In contrast, the sex ratio of the highland litters remained equal (Nature, DOI: 10.1038/nature09512). This suggests that temperature drives the sex of low altitude litters, while genes determine gender further up the mountain.

Pen thinks climatic pressures are behind these different systems. At low altitudes, females born early under warm conditions have more time to grow large and produce offspring, so it is advantageous for these skinks' gender to be temperature-sensitive. At higher altitudes, however, erratic annual temperatures mean that the timing of birth may not affect reproduction rates, so the skinks rely on genes to produce a balanced sex ratio.

http://www.newscientist.com/article/mg20827844.300-warm-weather-sets-lowland-skink-sex.html

Warm weather sets lowland skink sex

SNOW skinks can base their gender on either genes or temperature. Which strategy they choose appears to depend on the weather.


Ido Pen of the University of Groningen in the Netherlands and colleagues studied two clans of snow skinks, Niveoscincus greeni, living at low or high altitude in the mountains of Tasmania, Australia. The team captured pregnant skinks from each clan and allowed half of each group to lie in the sun for 10 hours per day, while the others were restricted to 4 hours. When the skinks gave birth, the scientists sexed their offspring.

Litters born to the lowland clan had a greater proportion of females after long days in the sun, compared to short days. In contrast, the sex ratio of the highland litters remained equal (Nature, DOI: 10.1038/nature09512). This suggests that temperature drives the sex of low altitude litters, while genes determine gender further up the mountain.

Pen thinks climatic pressures are behind these different systems. At low altitudes, females born early under warm conditions have more time to grow large and produce offspring, so it is advantageous for these skinks' gender to be temperature-sensitive. At higher altitudes, however, erratic annual temperatures mean that the timing of birth may not affect reproduction rates, so the skinks rely on genes to produce a balanced sex ratio.

http://www.newscientist.com/article/mg20827844.300-warm-weather-sets-lowland-skink-sex.html

Lizard Moving From Eggs to Live Birth

Evolution has been caught in the act, according to scientists who are decoding how a species of Australian lizard is abandoning egg-laying in favor of live birth.


Along the warm coastal lowlands of New South Wales, the yellow-bellied three-toed skink lays eggs to reproduce. But individuals of the same species living in the state's higher, colder mountains are almost all giving birth to live young.

Only two other modern reptiles—another skink species and a European lizard—use both types of reproduction.
Evolutionary records shows that nearly a hundred reptile lineages have independently made the transition from egg-laying to live birth in the past, and today about 20 percent of all living snakes and lizards give birth to live young only.

But modern reptiles that have live young provide only a single snapshot on a long evolutionary time line, said study co-author James Stewart, a biologist at East Tennessee State University. The dual behavior of the yellow-bellied three-toed skink therefore offers scientists a rare opportunity.

"By studying differences among populations that are in different stages of this process, you can begin to put together what looks like the transition from one [birth style] to the other."

Eggs-to-Baby Switch Creates Nutrient Problem
One of the mysteries of how reptiles switch from eggs to live babies is how the young get their nourishment before birth.

In mammals a highly specialized placenta connects the fetus to the ovary wall, allowing the baby to take up oxygen and nutrients from the mother's blood and pass back waste. (See related pictures of "extreme" animals in the womb.)

In egg-laying species, the embryo gets nourishment from the yolk, but calcium absorbed from the porous shell is also an important nutrient source.

Some fish and reptiles, meanwhile, use a mix of both birthing styles. The mother forms eggs, but then retains them inside her body until the very last stages of embryonic development.
The shells of these eggs thin dramatically so that the embryos can breathe, until live babies are born covered with only thin membranes—all that remains of the shells.

This adaptation presents a potential nourishment problem: A thinner shell has less calcium, which could cause deficiencies for the young reptiles.

Stewart and colleagues, who have studied skinks for years, decided to look for clues to the nutrient problem in the structure and chemistry of the yellow-bellied three-toed skink's uterus.

"Now we can see that the uterus secretes calcium that becomes incorporated into the embryo—it's basically the early stages of the evolution of a placenta in reptiles," Stewart explained.

Evolutionary Transition Surprisingly Simple
Both birthing styles come with evolutionary tradeoffs: Eggs are more vulnerable to external threats, such as extreme weather and predators, but internal fetuses can be more taxing for the mother.

For the skinks, moms in balmier climates may opt to conserve their own bodies' resources by depositing eggs on the ground for the final week or so of development. Moms in harsh mountain climates, by contrast, might find that it's more efficient to protect their young by keeping them longer inside their bodies.

In general, the results suggest the move from egg-laying to live birth in reptiles is fairly common—at least in historic terms—because it's relatively easy to make the switch, Stewart said.

"We tend to think of this as a very complex transition," he said, "but it's looking like it might be much simpler in some cases than we thought."

The skink-evolution research was published online August 16 by the Journal of Morphology.

Brian Handwerk

for National Geographic News
http://news.nationalgeographic.com/news/2010/09/100901-science-animals-evolution-australia-lizard-skink-live-birth-eggs/

Lizard Moving From Eggs to Live Birth

Evolution has been caught in the act, according to scientists who are decoding how a species of Australian lizard is abandoning egg-laying in favor of live birth.


Along the warm coastal lowlands of New South Wales, the yellow-bellied three-toed skink lays eggs to reproduce. But individuals of the same species living in the state's higher, colder mountains are almost all giving birth to live young.

Only two other modern reptiles—another skink species and a European lizard—use both types of reproduction.
Evolutionary records shows that nearly a hundred reptile lineages have independently made the transition from egg-laying to live birth in the past, and today about 20 percent of all living snakes and lizards give birth to live young only.

But modern reptiles that have live young provide only a single snapshot on a long evolutionary time line, said study co-author James Stewart, a biologist at East Tennessee State University. The dual behavior of the yellow-bellied three-toed skink therefore offers scientists a rare opportunity.

"By studying differences among populations that are in different stages of this process, you can begin to put together what looks like the transition from one [birth style] to the other."

Eggs-to-Baby Switch Creates Nutrient Problem
One of the mysteries of how reptiles switch from eggs to live babies is how the young get their nourishment before birth.

In mammals a highly specialized placenta connects the fetus to the ovary wall, allowing the baby to take up oxygen and nutrients from the mother's blood and pass back waste. (See related pictures of "extreme" animals in the womb.)

In egg-laying species, the embryo gets nourishment from the yolk, but calcium absorbed from the porous shell is also an important nutrient source.

Some fish and reptiles, meanwhile, use a mix of both birthing styles. The mother forms eggs, but then retains them inside her body until the very last stages of embryonic development.
The shells of these eggs thin dramatically so that the embryos can breathe, until live babies are born covered with only thin membranes—all that remains of the shells.

This adaptation presents a potential nourishment problem: A thinner shell has less calcium, which could cause deficiencies for the young reptiles.

Stewart and colleagues, who have studied skinks for years, decided to look for clues to the nutrient problem in the structure and chemistry of the yellow-bellied three-toed skink's uterus.

"Now we can see that the uterus secretes calcium that becomes incorporated into the embryo—it's basically the early stages of the evolution of a placenta in reptiles," Stewart explained.

Evolutionary Transition Surprisingly Simple
Both birthing styles come with evolutionary tradeoffs: Eggs are more vulnerable to external threats, such as extreme weather and predators, but internal fetuses can be more taxing for the mother.

For the skinks, moms in balmier climates may opt to conserve their own bodies' resources by depositing eggs on the ground for the final week or so of development. Moms in harsh mountain climates, by contrast, might find that it's more efficient to protect their young by keeping them longer inside their bodies.

In general, the results suggest the move from egg-laying to live birth in reptiles is fairly common—at least in historic terms—because it's relatively easy to make the switch, Stewart said.

"We tend to think of this as a very complex transition," he said, "but it's looking like it might be much simpler in some cases than we thought."

The skink-evolution research was published online August 16 by the Journal of Morphology.

Brian Handwerk

for National Geographic News
http://news.nationalgeographic.com/news/2010/09/100901-science-animals-evolution-australia-lizard-skink-live-birth-eggs/