Monday, January 31, 2011

Some Dinosaurs Survived the K-T Extinction Event



Dinosaur fossils are relatively rare, although high concentrations of remains do occur at a few localities. Moreover, the endemic nature of dinosaurs, in even closely spaced localities, has hindered the ability of science to confidently determine the biogeographic diversity, evolution, and radiation of these animals. These problems have been exacerbated by the fact that precise age determinations of dinosaur-bearing rocks have generally not been possible, due to a lack of precisely dateable rock layers, such as altered volcanic ash beds, in dinosaur-bone bearing strata. The San Juan Basin (SWB), of northwest New Mexico and southwest Colorado is one of the few places where a series of radiometric ages through Upper Cretaceous strata provides precise age constraints for the abundant and diverse dinosaur fossils found in these rocks. In addition, the ages of dinosaurs from Paleocene strata in the SWB have been tightly bracketed by fossil pollen and paleomagnetic data. James E. Fassett and colleagues present data that, for the first time, directly date SWB Cretaceous and Paleocene dinosaur-bone samples  based on laser-ablation, U-Pb methodology. Zircon U/Pb geochronology using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) is rapidly being adopted in the earth sciences. The use of this new tool to directly date dinosaur fossils may well revolutionize our understanding evolution. University of Alberta Press Release for Fasset et al. follows.


University of Alberta researchers determined that a fossilized dinosaur bone found in New Mexico confounds the long established paradigm that the age of dinosaurs ended between 65.5 and 66 million years ago.The U of A team, led by Larry Heaman from the Department of Earth and Atmospheric Sciences, determined the femur bone of a hadrosaur as being only 64.8 million years old. That means this particular plant eater was alive about 700,000 years after the mass extinction event many paleontologists believe wiped all non-avian dinosaurs off the face of earth, forever.


Heaman and colleagues used a new direct-dating method called U-Pb (uranium-lead) dating. A laser beam unseats minute particles of the fossil, which then undergo isotopic analysis. This new technique not only allows the age of fossil bone to be determined but potentially can distinguish the type of food a dinosaur eats. Living bone contains very low levels of uranium but during fossilization (typically less than 1000 years after death) bone is enriched in elements like uranium. The uranium atoms in bone decay spontaneously to lead over time and once fossilization is complete the uranium-lead clock starts ticking. The isotopic composition of lead determined in the hadrosaur's femur bone is therefore a measure of its absolute age.


Currently, paleontologists date dinosaur fossils using a technique called relative chronology. Where possible, a fossil's age is estimated relative to the known depositional age of a layer of sediment in which it was found or constrained by the known depositional ages of layers above and below the fossil-bearing horizon. However, obtaining accurate depositional ages for sedimentary rocks is very difficult and as a consequence the depositional age of most fossil horizons is poorly constrained. A potential weakness for the relative chronology approach is that over millions of years geologic and environmental forces may cause erosion of a fossil-bearing horizon and therefore a fossil can drift or migrate from its original layer in the strata. The researchers say their direct-dating method precludes the reworking process.


It's widely believed that a mass extinction of the dinosaurs happened between 65.5 and 66 million years ago. It's commonly believed debris from a giant meteorite impact blocked out the Sun, causing extreme climate conditions and killing vegetation worldwide.


Heaman and his research colleagues say there could be several reasons why the New Mexico hadrosaur came from a line of dinosaurs that survived the great mass extinction events of the late Cretaceous period (KT extinction event). Heaman says it's possible that in some areas the vegetation wasn't wiped out and a number of the hadrosaur species survived. The researchers also say the potential survival of dinosaur eggs during extreme climatic conditions needs to be explored.


Heaman and his colleagues believe if their new uranium-lead dating technique bears out on more fossil samples then the KT extinction paradigm and the end of the dinosaurs will have to be revised. The research was published online, January 26, in the journal, Geology.


Citations
Fassett, J.E., L.M. Heaman, and A. Simonetti,  2011. Direct U-Pb dating of Cretaceous and Paleocene dinosaur bones, San Juan Basin, New Mexico. Geology (2011),39(2):159. doi:10.1130/G31466.1


Paton, C., J. D. Woodhead, J. C. Hellstrom, J. M. Hergt, A. Greig, and R. Maas. 2010.Improved laser ablation U-Pb zircon geochronology through robust downhole fractionation correction, Geochem. Geophys. Geosyst., 11, Q0AA06, doi:10.1029/2009GC002618.

Sunday, January 30, 2011

Ending Rattlesnake Roundups


Rattlesnake Roundups look like something from the mid 19th century. As immigrants swarmed over California in search of gold, feeding all of those people became a challenge, market hunting became a lucrative source of income for many. John James Audubon recognized the problem as early as 1821 when he estimated 48,000 plovers were killed in a single day at Lake St. John, Louisiana. However, rattlesnake-roundups are a product of the mid 20th century. The JAYCEES (Junior Chamber of Commerce), in Sweetwater, Texas invented the modern rattlesnake roundups to raise money and draw attention to their local businesses in 1958. If you visit the Sweetwater Jaycees Rattlesnake Roundup Facebook Page, you will discover the organization's mission is helping local children's groups (Boy & Girl Scouts, Softball & Baseball, Pee Wee Football, Soccer, Christmas 4 Kidz Roping, Thanksgiving Day Feed, MHMR Christmas Party, and Annual Easter Egg Hunt). Thus, the destruction of wildlife is done in the name of good works. 

The Rattlesnake Roundup in Whigham, Georgia is said to attract 40,000 visitors, and be one of the premier events in the Southeast (USA). On their web site they actually have the following statement.
"This event includes such demonstrations as the now-famous milking of the venom from an Eastern Diamondback Rattlesnake. This venom is always used for medical research. Ken Darnell, a handler at last year’s event said,
"One of the worst problems you suffer from snake bite is your blood pressure goes down. It can go down tremendously. And now, one of the most effective blood pressure medicines in the world came about because of studying rattlesnake venom. They produced a synthetic pharmaceutical for blood pressure treatment -- very effective. Hey, they did it with our venom produced at roundups in Georgia and Texas."
Sorry guys, the ACE Inhibitor used to lower blood pressure was discovered in the Brazilian Jararaca (Bothrops jararaca), not a Whigman, Georgia Eastern Diamondback.  

The Whigham Georgia Rattlesnake Roundup was held recently (January 29, 2011) and one commentator reports 81 snakes were collected. The event continued despite the efforts of the Center for Biological Diversity to get the Attorney General of Georgia to prevent the hunters from gasing gopher tortoise burrows and transporting (illegally) rattlesnakes across state lines (at least some of the snakes are collected in Florida).


In some communities rattlesnake roundups have been converted into to less harmful events. Fitzgerald, Georgia has a Wild Chicken Festival and San Antonio, Florida promotes The Rattlesnake Festival, with captive snakes and wildlife education events. They no longer collect and kill rattlesnakes. Both festivals have reportedly met with great success.

But apparently stubbornness, accompanied by a little ignorance, has prevented some communities from transforming the roundups into ecologically friendly activities. Both the Whigham and Claxton rattlesnake roundups continue, despite offers to help convert them into less harmful activities by OneMoreGeneration.org.


Saturday, January 29, 2011

Were Ichthyosaurs Homeothermic?


The ichthyosaurs are a group of extinct reptiles with a dolphin-shaped body, adapted to a marine life-style that are known from many well preserved fossils but lack modern descendants. Their origin has been controversial, but cladistic methods have recovered them as diapsid reptiles, a clade that includes the Lepidosauromorpha (Beak-heads + Lizards and Snakes) and Archosauromorpha (many extinct groups + dinosaurs + crocodiles). And, it is possible that ichthyosaurs are the sister to the lizards (Sauria). In time, they are known from the Triassic to the Late Cretaceous (about 250 to 95 million years ago).

Mixosaurus fossils are cosmopolitan and have been recovered from Triassic rocks in continental Asia, Indonesia, Europe, Canada, Alaska, and the lower USA.  The name, provided by George Baur in 1887, refers to its mixed morphology suggesting it was in transition between a terrestrial and marine lifestyle. Less than two meters long, Mixosaurus had: a long tail with a low fin; a dorsal fin; paddle-shaped limbs with five digits; and long, narrow jaws. Thus, it may have been a slow swimmer, which ate fish. Because of these characters Mixosaurus are considered basal ichthyosaurs – species close to the ancestral ichthyosaur. .

Christian Klob and colleagues (2011) have now done the first histological examination of ichthyosaur bone on a series of specimens that range from very young specimens (about 50 cm) to large adults (about 1.2 m). Previous research had shown that juvenile Cretaceous ichthyosaur (non-Mixosaurs) bones had woven-fiberous tissue accompanied highly vascularized spongy bone was replaced with more dense bone. But, Mixosaurus had not been studied and were of interest because of their basal characters and early appearance in the geological record.

The study used bones (femur, fibula, ischium, ulna, phalanges, scapula, rib, and gastral rib fossils) that were cut, ground, and section so that the fossilized cellular structure could be seen with a light microscope. Growth marks were present in most of the bone samples and ontogenetic changes could be traced, although resorption had deleted part of the growth record. The high growth rate of Mixosaurus implies relatively high metabolic rates, a precondition for being homoeothermic. Warm-blooded physiology had been previously proposed for some of the large deep-water, ocean-cruising ichthyosaurs and it now seems likely that it was also present in their ancestors.

Citation
Kolb, C., M. R. Sánchez-Villagra and T. M. Scheyer  2011. The palaeohistology of the basal ichthyosaur Mixosaurus (Ichthyopterygia, Mixosauridae) from the Middle Triassic: Palaeobiological implications. Comptes Rendus Palevol, doi:10.1016/j.crpv.2010.10.008 

Friday, January 28, 2011

Lonesome George Meets Two New Females

 The Huffington Post is reporting the following story:

QUITO, Ecuador — Will Lonesome George ever become a dad? Scientists are still hoping to mate the near century-old giant tortoise from the Galapagos – even though efforts over the past two decades have failed. The Galapagos National Park said in a statement Thursday that they are providing two new female partners for George, who is believed to be the last living member of the Geochelone abigdoni species. George is estimated to be between 90 and 100 years old – and could have at least 50 more years ahead of him. For the past 20 years, he has lived with two previous female partners, of the similar but different Geochelone becki species. The females laid eggs in 2008, 2009 and last year, but none resulted in viable offspring. Scientists believe George may have a better chance of reproducing with his two new partners, of the Geochelone hoodensis species. The two potential mates arrived on Santa Cruz island, where George lives, on Thursday from the archipelago's Spanish Island. Genetic studies conducted by Yale University have shown that the newly arrived tortoises "are genetically closer ... more compatible, and could offer greater possibilities of producing offspring," the park's statement said. The Galapagos island chain, about 620 miles (1,000 kms) off Ecuador's coast, is home to unique animal species that inspired Charles Darwin's ideas on evolution.

Thursday, January 27, 2011

A New, Tiny, Two-toed Flea Toad

This illustration of a related species,
Brachycephalus ephippium shows the 
reduced digits on the hands and feet.
The family Brachycephalidae holds 47 species in two genera, Brachycephalus and Ischnocnema. These anurans have toad-like bodies, don’t jump very far, and are often brightly colored with yellow or orange on the dorsum. The 16 members of the genus Brachycephalus are commonly known as Saddle-back Toads due to the presence of bony shields above their vertebrae, or Pumpkin Toads, because of the bright orange or yellow coloration of some species. But, two species: B. didactylus and B. hermogenesi are known as flea toads because of their exceptionally small size, they are in the 8 to 9 mm range. Marcello Felgueiras Napoli and colleagues have now described a new species of flea toad from Brazil’s Atlantic Forest. The new species, Brachycephalus pulex, was found on Serra Bonita Mountain which contains a remnant of the Atlantic rainforest and is within the Municipality of Camacan, Bahia, Brazil, this locality represents the northernmost record for the genus. Brachycephalus pulex was found in the leaf litter and on a tree trunk in an area that is 800- 930 m above sea level, is only known from the type locality. Four specimens were between 8.0 and 8.4 mm in body length. Perhaps the most remarkable aspect of this tiny frog are its greatly reduced fingers and toes, there are two digits or digit remnants on each appendage.  


Citation
NAPOLI, M. F., U. CARAMASCHI, C. A. GONÇALVES CRUZ and I. RIBEIRO DIAS. 2011. A new species of flea-toad, genus Brachycephalus Fitzinger (Amphibia: Anura: Brachycephalidae), from the Atlantic rainforest of southern Bahia, Brazil. Zootaxa 2739: 33–40

Tyrannosaurus rex was a Hunter


There are risks to being a scavenger - picking up parasites or disease-causing microorganisms, and not being able to find food or get to it quickly because of distance are issues faced by scavengers. Predators on the other hand have to locate and kill prey - skills that require time and patience. While most large carnivores combine scavening and hunting a few specialize, doing one or the other. There has been a debate over the feeding habits of Tyrannosaurus rex - was it a scavenger or a hunter? Chris Carbone of the Zoological Society of London and colleagues have addressed this question in a new paper. What follows is a press release from the Proceedings of the Roloyal Society B. The full article can be found on-line. Just click the link below.

T.rex hunted like a lion, rather than regularly scavenging like a hyena, reveals new research published in the journal Proceedings of the Royal Society B.

The findings end a long-running debate about the hunting behaviour of this awesome predator.

Scientists from ZSL used an ecological model based on predator relationships in the Serengeti to determine whether scavenging would have been an effective feeding strategy for T.rex.

Previous attempts to answer the question about T.rex’s hunting behaviour have focused on its morphology. The flaw in this approach is that two species can possess similar physical features and still have very different hunting strategies, such as vultures and eagles.

Lead author Dr Chris Carbone, says “By understanding the ecological forces at work, we have been able to show that scavenging was not a viable option for T.rex as it was out-competed by smaller, more abundant predatory dinosaurs.

“These smaller species would have discovered carcasses more quickly, making the most of ‘first-come-first-served’ opportunities.”

Like polar bears and lions, the authors conclude that an individual T.rex would have roamed over large distances to catch its prey, potentially areas several times the size of Greater London.

This research now opens the door to look at the behaviour of T.rex as a hunter.

Carbone, C., S. T. Turvey, and J. Bielby. 2011. Intra-guild competition and its implications for one of the biggest terrestrial preadtors, Tyrannosaurus rex. Proceedings of the Royal Society B. doi: 10.1098/rspb.2010.2497


Wednesday, January 26, 2011

Europe’s Most Endangered Viper


Vipera ursinii macrops from Mount Dinara,
Croatia. Photo credit: Zwentibold
The Meadow Viper’s (Vipera ursinii) wide distribution is heavily fragmented. The small viper is found in Italy, France, Hungary, Romania and the Balkan Peninsula. And, it is thought to be extirpated from Bulgaria, the Republic of Moldova and Austria; making it the most endangered viper in Europe. Its ecology has been studied in several locations but, a population in Romania’s Danube Delta has been neglected. Alexandru Strugariu and colleagues have now examined the Danube Delta population and estimate it contains 321 individuals in a 62 hectare area. Juveniles were present in their sample, and gravid females composed half the specimens captured. They found microhabitats and activity patterns varied with age and sex of the individuals and suggest these are linked to changes in feeding and reproductive activity. Gravid female viper were active in the early morning, in low areas and in microhabitats that were open with salt-tolerant vegetation; while non-gravid females were more active during later hours and only in bush grass habitats that were dense. 

The Romanian Danube Delta population of the Meadow viper coincides with the Danube Delta Biosphere Reserve so it is at least in part protected. The population is recognized as V. u. moldavica, a subspecies known from Romania, Bulgaria, and Moldova.

Citation
Strugariu, A., S. R. Zamfirescu, I. Gherghel, T. C. Sahlean, V. Moraru & O. Zamfirescu. 2011. A preliminary study on population characteristics and ecology of the critically endangered meadow viper Vipera ursinii in the Romanian Danube Delta. Biologia 66:175-180.

Tuesday, January 25, 2011

A New Species of Wolf Snake from Yunnan China

There are more than 40 species of  Asian Wolf Snakes in the genus Lycodon. Gernot Vogel and Patrick David have now described Lycodon synaptor from Yunnan Province in China. The new species can be recognized by the combination of the loreal scale not entering orbit; and its narrow dorsal bands, with the first band starting at ventral 5–9. Most other characters are shared with Lycodon fasciatus. The species is indirectly named in honor of Dr. Wolfgang Böhme for his efforts to unite professional and amateur herpetologists. There is no information available on the biology of Boehme’s Wolf Snake, but the region it comes from - Dongchuan - is mountainous.

Vogel, G. and P. David. 2010. A new species of the genus Lycodon ) Boie, 1826) from Yunnan Province China (Serpentes: Colubridae). Bonn Zoological Bulletin 57:289-296.

Monday, January 24, 2011

Gopher Tortoise Restoration

The Daytona Beach News-Journal is carrying the following story.
56 Gopher tortoises to get new digs
Volusia plans to improve food, habitat for critters
By DINAH VOYLES PULVER, Environment Writer

A sandy ridge near Barberville in northwestern Volusia County soon will get a new look in an effort to boost the area's population of protected gopher tortoises.

It's part of a long-term, statewide plan by the Florida Fish and Wildlife Conservation Commission to create better places for the tortoises -- and related species that share their homes. The wildlife commission is doling out a limited amount of cash each year to local agencies willing to do land restoration.

The Volusia project will take place in the sprawling Heart Island Conservation Area, 14, 246 acres east of Barberville on either side of State Road 40. The St. Johns River Water Management District plans to perform the work on 227 acres of a parcel it owns jointly with Volusia County.

Before acquisition, the land was used for trophy game hunting, and oaks were planted to produce acorns, said Ed Garland, a district spokesman.

The district plans to put in fire lanes to burn the land with prescribed fire on a regular basis and will apply herbicide in the spring to treat the oaks that create too much shade, Garland said.

The Volusia County Council approved the plan last week.

Burning and reducing the oaks will create more sandy areas and increase food available for the tortoises, said Deborah Burr, gopher tortoise plan coordinator for the wildlife commission. A survey last fall found an estimated two adult tortoises per acre on the land.

Like many Florida plants and animals, tortoises need fire to prevent undergrowth from getting so thick that it's difficult for them to crawl, find food and build burrows.

"Fire plays a huge role in their life cycle," Burr said, "and is a huge part of the plan to sustain the species."

Experts say projects that improve tortoise habitat also benefit as many as 300 additional species of animals and insects that share tortoise burrows.

The wildlife commission adopted a tortoise management plan in 2007, listing goals for protection and restoring habitat. Burr said the lack of good quality habitat is one reason why tortoises declined statewide.

The tortoises were used by old-timers for food before the state banned their harvest in 1988. Their status on the state's protected species list was upgraded to threatened in 2006.

In 2009, the U.S. Fish and Wildlife Service said the tortoise might warrant placement on the federal protected species list, but a spokesman for the service said Wednesday the issue is still under review.

The statewide population was estimated at about 750,000 in 2007, when the wildlife commission said it would no longer allow tortoises to be buried alive during construction and would instead require them to be relocated.

However, hundreds of permits already had been issued for tortoise destruction and many are still outstanding.

The wildlife commission estimated as many as 94,000 tortoises may have been buried on construction sites between 1991 and 2007. Developers with the old permits can choose to voluntarily relocate gopher tortoises, and wildlife commission officials have said they encourage the permit holders to relocate.

The money for the Heart Island restoration, $13,168, will come from cash paid by developers as mitigation for destroying gopher tortoise burrows.

This year, the wildlife commission is spending about $135,000 on 12 projects, Burr said. Last year, it distributed about $119,000.

The wildlife commission collects proposals from local governments and then prioritizes them based on the cost per acre price of the work, Burr said.

The wildlife commission is looking for the "biggest bang for its buck," she said. "We're looking for management of the most amount of land for the least amount of money possible."

Saturday, January 22, 2011

Detecting Snakes: Experimental Results

Early in my teaching career I kept a captive born squirrel monkey in a classroom laboratory along with a variety of lizards and snakes. Once the monkey realized snakes were present, it would scream, race back and forth in its cage and literally bounce off-the-walls in a display that was impossible to ignore. After seeing the snakes the monkey respond with the same display towards completely harmless objects that were snake-shaped, like ropes and garden hoses. Research over the past 20 years has suggested humans have evolved the ability to detect snakes as a threat – an attentional bias – that has served to warn humans of a snake’s presence before it has an opportunity to bite.  This mechanism involves fear of snakes as well as a visual sensitivity to objects shaped like snakes, most likely a detection mechanisms similar to the ones found in monkeys.

Vanessa Lobue, of Rutgers University, and Judy Deloache, at the University of Virginia, have recently published the results of a series of experiments using touch screen technology with preschool children and adults. The subjects were presented with 3x3 matrices of color photographs and asked to touch a target on the screen as quickly as possible. Based on previous research, parallel results were expected for the adult and the preschool participants; they expected adults would respond more rapidly than the children, but that the two age groups would display the same pattern of performance. The subjects responded to snakes much more rapidly than frogs as expected. In one experiment they found the color of the snake was not important in detection; but other experimental sets suggest recognizing a coiled object (coiled snake vs. a coiled wire vs. flower); the coiled snake and coiled wire were detected more rapidly than the flower. But the differences between detecting the snake and detecting the wire were not statistically significant. In another experimental set and one using a snake stretched out, the coiled snake was detected more rapidly.

It seems likely that human fear as well as human obsession with snakes have an evolutionary origin and will keep psychologists busy for sometime trying to understand the impact of snakes on the human brain.

Citation
Lobue, V. and J. S. Deloache. 2011. What's so special about slithering serpents? Children and adults rapidly detect snakes based on their simple features. Visual Cognition, 19(1):129-143

Friday, January 21, 2011

Monitor Lizard Mortality Due to the Cane Toad?


ABC Western Queensland is carrying the following story that reports anecdotal evidence that the Cane Toad is the cause of increased mortality in Varanus populations of the Cooper drainage. This is unedited.

20 January, 2011 3:37PM AEST

Cane toads in the Cooper threaten predators

By Nicole Bond and Julia Harris

Cane toads first arrived at Noonbah station homestead near Stonehenge, in March last year, although they were seen at a neighbouring property, Lochern, about six months earlier. Now, with a boom season in the district, the toad numbers are increasing, and Angus Emmott, a grazier and naturalist said he's starting to see their impact on goannas. He said the cane toads are just breeding like crazy.

"There's young ones everywhere but there's also lots of big ones," he said.

The issue of concern to Mr Emmott is he's now noticing that the goannas in particular are starting to die at Noonbah.

"I'm seeing goanna bodies lying around and anything like mulga snakes, De Vis banded snakes; any of those animals that have frogs as a significant component of their diet are really going to be hammered," he explained.

Mr Emmott said he hasn't seen a dead goanna with a cane toad in its mouth but the evidence from northern Australia is overwhelming.

"When the cane toads first move in, you get a mass die off of these particular groups of animals."

The promising part for Mr Emmott seems to be that over a period of about 20 years, the few goannas that do survive gradually learn to live with the cane toads and leave them alone.

He's hoping that will occur in the Cooper system over time as well.

"But we've probably got 15 to 20 years to wait until the goanna populations come back up to any sort of numbers again," he explained.

He said the goannas and other frog eating animals have a major role in the balance of the ecosystem and that's going to change.

"But without close, intense study we're probably not even going to be aware of what exactly those impacts are."

A number of scientists are interested in the invasion of cane toads into the Lake Eyre Basin catchments, and Mr Emmott said it's because it wasn't something that was predicted.

"It was thought that this part of the world would be too arid for them.

"They seem to be adapting quite well to the aridity; although it's not very arid at the moment!

"Sydney Uni had a student working around the Longreach area last summer and I'm sure if they can get some more money together they'll be doing some more work," said Mr Emmott.

Thursday, January 20, 2011

A New Report fron Roger Repp


Howdy Herpers,

The last report centered on chuckwallas. It was sent out one damn day too soon--for I got a much better picture of one of them the next day. Pic 1 is of a chuckwalla found just east of the Picacho Mountains on 4 December 2010, (note the juvenile tail pattern), and the second is of the one just above the dead  tortoise at Ragged Top. Both were very difficult photos to get.

The petroglyphs shown in pic 3 were found by my wife Dianna and I on her birthday. In all, we saw  round 50 boulders thusly decorated by the ancient ones. From what I saw on these rocks, these ancients ones were either well endowed--or at least fancied that they were.

Pic 4 is of one of TWO Gila Monsters in what I call the "Marco Polo" den. I now have enough characters on this animal to backtrack through all Suizo Monsters to see if we know him. But I have not yet done that. Past experience has taught us that whenever there are two in a den together, they are normally boy/girl. And the male is usually the one in front.

Pic 5 and 6: HESU Den Number 1, outside and inside the Gila hole. I still have not seen enough  of this monster to ascertain who he is, but I expect he is HS9--The Pilgrim. While I have yet  to see her, the signal plainly indicates that female HS13 "Farrah" is behind him. And The Pilgrim is acting
like there is something behind him--as he is visible with every visit this winter. They usually wiggle backwards at our approach, but he is staying put during all of our inept attempts to photo him. So, I'm saying this is pairing number 2 on our hill. This den has been utilized by several different monsters through the years, going back to our first study subject HS1, "Geronimo." He was captured in this hole in March 2001.

Pic 7: "The Monster of the Decade"--the Lazy M monster-still home on Hill 97. While I also suspect a pairing here, that is pure speculation. I have been watching this lair since November of 2000. In 2005, there were three monsters stacked like cordwood in the entrance way where you seeing Lazy M. Three is the most I've ever seen in one hole.

Pic 8: A photo of the alpha male Crotalus atrox in a den I call "ADO." (Atrox den # 0). It's a long story how it earned that number, so I will spare you that detail. But I found the place in 1998, and it had as many  as six atrox in it at its peak. By 2005, the den died, and stayed that way until 2010. I have counted five atrox in the hole, and expect that they are all still there--tucked behind the alpha male. "Hiding the girls" is a commonly observed behavior with atrox as well as Gila Monsters during the colder months.

Pic 9 and 10: The first time ever witnessed in over 20 years of herping Arizona, a tiger rattlesnake 100% out of crevice basking in January. Previously, I've seen them out like this every month except January. This is CT#6, "Gracie." I'm thinking I see a food bolus in her flank, but that could be a relic of something underneath her. It was suggested that she might be basking because she is pregnant. As she has given birth two consecutive years in a row now, that would be incredible! In the 15 minutes it took me to do her write up, her body temps increased dramatically. The temp near her coil was 40 C! (~104 degrees F)

Pic 11: The view from the Marco Polo HESU Den on our hill, looking south. What a view our mystery monster has--eh?

Best to all, roger

More on the Northern Pine Snake vs Walmart


Two recent news stories suggest the battle between the Northern Pine Snake (Pituophis melanoleucus melanoleucus) and the Jaylin Holdings Company is continuing. The State of New Jersey reached a tentative agreement with the developer that would allow the construction of a Walmart store on 21 acres of Pinelands off Route 37 on the Toms River and Manchester border. The trade off is reportedly a 212 acre forest preserve adjacent to the Walmart that would contain five hibernacula constructed by the developer, as well as other environmental enhancements that would thin the forest canopy and provide a favorable environment for the snake. Critics consider this a bad deal for the pine snake, and suggest it will not make up for the damaged habitat. They also note that the developer tried to remove the pine snake from the endangered species list. The New Jersey DEP has apparently encouraged Jaylin to search for a store location that had been previously developed, but the firm claims it was unable to find a suitable alternative site. The DEP anticipates entering into the settlement agreement subject to public comments and review of those comments by the department. A notice of the proposed settlement will be published in the new issue of the DEP Bulletin at http://www.nj.gov/dep/bulletin/index.html

On January 19, 2011, the Sierra Club asked the state Department of Environmental Protection to extend the public comment period by 45 days, stating that the development project will have significant impacts on threatened and endangered species and their habitat and that storm water runoff and nonpoint source pollution will enter Barnegat Bay.

A survey detected a snake and a hibernaculum the property, and the debate that followed over the state's role in saving habitat for the threatened species has been the main roadblock for Walmart. The Northern Pine Snake was once abundant in southern New Jersey but has disappeared from populated areas but still maintains populations in the Pine Barrens of Ocean County, NJ. 

Literature
Hester, T. 2011. N.J. DEP tentatively agrees to allow Walmart store in Pine snake neighborhood.  newsroomjersey.com

Moore, K. 2011. More time sought for comments on planned Walmart in Toms River. APP.com. January, 18, 2011.


Wednesday, January 19, 2011

A Displaced Snake Story From Australia

 The flooding in Australia has produced numerous stories about displaced snakes. Here is just one from the Gympie Times (a Queensland News outlet).

Snakes Look For new Food Supply
Carly Morrissey,  20th January 2011

For Gympie snake catcher John Keady all the recent flooding rain means snakes, snakes and more snakes.
“I’ve been flat out like a lizard drinking,” Mr Keady said this week. “There’s snakes coming out of our ears, they’re very, very active.”Flooding in Gympie meant snakes headed for higher ground and now that waters have receded there are a lot of displaced snakes in unfamiliar territory. The worst part, Mr Keady said, is the flood has moved or killed the snakes’ normal food supply. He said rats and mice have been drowned or moved to higher ground and in the next few days there will be a “pile” of snakes all out looking for food, following their scent. Passionate about snakes and all animals Mr Keady is just thankful that people call him to relocate the snakes. “At least we can be there to save them,” Mr Keady said. He has been around the region with his son catching and relocating snakes to the bush during the last week. Recently the pair has caught snakes in Gympie, on the Southside, in the Forestry complex, at Cedar Pocket, Tewantin and Noosa.
Yesterday Mr Keady was called to catch a carpet snake at Nambour. He had also caught a green tree snake, red belly black snake and a brown snake. “I’ve had 12 calls this morning (Wednesday).” He said the majority of calls were for snakes that had found their way into homes to try and stay dry during the rain and flood.
Some of their natural homes would have been flooded and other food sources would have been killed. This has led to some close calls with people and a busy time for Mr Keady. But the snake trainer said it wasn’t just snakes that have been displaced due to flooding. He had been receiving calls about possums taking up residence in people’s homes and sheds.

Tuesday, January 18, 2011

More on Minnesota Rattlesnake Habitat



HOUSTON COUNTY, Minn. — Rattlesnakes were a part of life for Ken Visger. The cold-blooded creatures slithered down to catch a few sun rays, winding up in his lawn, near the shed and on his doorstep. Sometimes they wound up under the blades of Visger’s riding lawn mower. His wife, Terry, lost two dogs to their bite. “People always said ‘Oh you’ll never find them in your yard,’” she said. “That’s where we found them.” Visger, 64, recently agreed to an easement that will help conserve the rattlesnake’s bluff prairie habitat in the hills that surround his farm. The effort should keep poisonous snakes away, Visger said. The 145-acre easement, held by the Minnesota Land Trust, requires regular maintenance of the fading ecosystem — a rare type of prairie that forms on steep, south-facing inclines of bluffs in southeastern Minnesota, southern Wisconsin, and parts of Iowa and Illinois.

The easement on Visger’s property is the first by the non-profit’s bluff Prairie Protection Initiative, funded by a $5 million grant from the state. The effort aims to protect as many as 500 acres of bluff prairie.
Snowy clearings dotted the south side of three hills surrounding Visger’s property, where trees and invasive brush were pulled, felled and burned to restore prairie. Visger worked with the Department of Natural Resources on solutions and hired a contractor who spent more than a month clearing overgrowth.
The change in wildlife was easy to see, Visger said. Restoration brought more mammals and more birds.
And, so far, the rattlesnakes seem content to sun in the freshly cleared bluffs.

“Now they have no reason to come off,” Visger said.
More than 9,000 rocky limestone bluffs line the Mississippi River in southeast Minnesota, supporting about 50,000 acres of bluff prairie — also called goat prairie — one of the rarest habitats in the state, said Jaime Edwards, a non-game wildlife specialist for the DNR. Many of the area’s sloping hills are filled with cedar trees and invasive brush like buckthorn that create a canopy over a landscape once speckled by open grassland and wildflowers.

“The bluffs in Winona are just horrendous with invasive brush,” Edwards said. “It’s depressing actually.”
The state has 100 easements on about 8,100 acres in its Native Prairie Bank program, according to department staff. Residents still own and pay taxes on the land and are responsible for conservation and land management.

Before European settlement, periodic fires kept cedar trees from dominating the bluffs, Edwards said.
An early land survey that predates Minnesota’s statehood describes “bold exposures of rock, with a grassy bank beneath,” and prairies mixed with trees.

“On summit levels spreads the wide prairie,” reads survey, conducted in 1854 for the federal government. “It’s long undulating waves stretching away till sky and meadow mingle in the distant horizon.”

Timber rattlesnakes — protected in Wisconsin and listed as threatened in Minnesota — rely on prairies to maintain body heat and use cracks in limestone to hibernate in the winter.

The rattlers establish a territory, traveling varying distances, finding sunny openings to warm up, said Bob Hay, a former herpetologist for the Wisconsin DNR. Hay tracked snake movements off and on for almost 10 years with surgically planted transmitters.

“Most of the snakes in Wisconsin require a lot of sunshine,” he said. “Canopy reduces the overall temperature and can reduce body temperature enough to influence breeding.”

Tree overgrowth forces snakes down the bluff to areas developed by the human population, increasing the likelihood of sightings and attack, Edwards said. Researchers found rattlesnakes in about 15 to 20 percent of 450 of bluffs surveyed in Minnesota.

In the spring, the DNR will put an easement on another 30 acres of Visger’s land. He is offering the easement to the state as a donation, Visger said. His own conservation work helped him see the importance of preserving the area’s natural wildlife, he said.

“These are the plans to restore what we had before we screwed it up,” Visger said. “We’re the worst invasive species of all.”

Convergence of Infrared Vision in 3 Snake Clades


Three families of snakes use infrared waves to detect prey and differences in environmental temperatures. The mechanism involved in this has only been recently discovered to involve the transient receptor potential (TRP) ion channels. TRPs are involved in various biological processes, including calcium and magnesium homeostasis, neuronal growth, temperature sensation, and pain sensation. The sensations caused by the pungent agents of wasabi and other mustard plants are generated by our transient receptor potential ankyrin 1 (TRPA1) channel. Recently, it has been discovered that the orthologous receptors (receptors sharing a common ancestral gene) of the western diamondback rattlesnake (Crotalus atrox), ball python (Python regius), and garden tree boa (Corallus hortulanus) detect infrared radiation, while those the Texas rat snake (Pantherophis obsoletus lindheimeri) does not. The genetic mechanism of infrared sensitivity of these snake-specific TRPA1 proteins is unknown. Yokoyama et al. (2011) have now identified the amino acid changes that are responsible for the dramatic functional changes in the three groups of snakes. They suggest three parallel amino acid changes (L330M, Q391H, and S434T) are responsible for the development of infrared vision in the three groups of snakes. Protein modeling shows that the three amino acid changes alter the structures of the central region of their ankyrin repeats. The article can be found on-line.

Citation:
Yokoyama, S., A. Altun, and D. F. DeNardo. 2011. Molecular convergence of infrared vision in snakes. Molecular Biology and Evolution  28(1): 45-48. doi:10.1093/molbev/msq267

Monday, January 17, 2011

Testing for Mercury in Amazonian Turtles


Giant River Turtle (Podocnemis expansa)
Mercury (Hg) in the food webs of the Amazon Basin have been studied since the 1980s and its presence was first attributed to its uncontrolled use artesanal gold mining. However, in the early 1990s, high levels of Hg were found in soil, fish, and hair of local individuals far from any anthropogenic sources. In the upper Rio Negro, a small gold-mining operation developed in 1993, but was shut-down by the Brazilian Government. This basin, located on the border of Brazil, Colombia, and Venezuela, is strongly protected and has no mining activity or any other known anthropogenic Hg sources.  Mercury concentrations in the soil are naturally high and the metal is probably transported into river systems by runoff. Turtles in this region have been an important commercial and protein source for local residents for centuries and they continue to be exploited today. Rio Negro Basin turtles also supply the markets in Manaus, the Amazonas state capital. The species most often used are the podocnemidids: Podocnemis expansa, P. erythrocephala, P. sextuberculata, P. unifilis, and Peltocephalus dumerilianus.  Podocnemis are all listed in the IUCN Red List of Threatened Species with P. expansa listed as in Low Risk/Conservation Dependent species, and the other species listed as Vulnerable. 

Schneider et al. (2011) determined the concentrations of mercury (Hg) in four tissues of six species of turtles from the Rio Negro.  They found two species that had mercury concentrations in blood and carapace tissues that were correlated with concentrations in internal tissues. This serves as a way to establish a non-lethal indicator of internal metal exposure or body burden of Hg. Mercury levels were also correlated to turtle size and gender. The liver in five species of turtles had the highest concentration, followed by carapace, muscle, and blood. The exception was Chelus fimbriatus, which had a higher metal concentration in the muscle than carapace. The use of carapace tissue to infer internal concentrations of Hg is commonly used in freshwater and sea turtles, but this study found that only blood might be a reliable indicator of Hg concentrations in liver and muscle tissues for P. sextuberculata. Thus blood may be used as a non-invasive method to study concentrations of Hg in liver and muscle of P. sextuberculata. The entire article can be found on-line. 

Citation
Schneider, L., L. Belger, J. Burger, R. C. Vogt, C. Jeitner,  J. R. P. Peleja.  2011. Assessment of non-invasive techniques for monitoring mercury concentrations in species of Amazon turtles. Toxicological & Environmental Chemistry, 93(2):238-250.

Saturday, January 15, 2011

The Viviparous Lizard – Clues to Understanding the Transition


Watching a female squamate giving birth or lay eggs is similar in many ways, peristaltic waves move the embryo or the egg to the cloaca and the opening expands to allow the next generation to enter the world. Egg laying is an ancestral trait in squamates - but live birth has evolved numerous times in many different clades. Over the years I have had occasion to incubate Bullsnake, Fox Snake, and Green Snake eggs. In the first two species incubation time was at least eight weeks, while the Green Snake eggs, much to my surprise, hatched within about two weeks of being laid. Female Green Snakes hold their eggs for longer periods of time, the embryo is at a more advanced state of development, before the female deposits them in a nest – a trait thought to be one step in the transition between being oviparous and viviparous.

Transitioning between laying eggs and giving live birth has been considered the result of gradual changes, but it is well known that populations of some egg-laying species have live-birth so gradual may not be the correct adjective. The Viviparous Lizard is such a species. It is widely distributed in Eurasian, from Spain, Italy, Serbia, Bulgaria and Macedonia in the south it ranges northward into the Arctic Circle. In the Alps it can be found as high as 3000 m above sea level. The more southerly populations lay eggs, while populations at higher latitudes have live birth.

Male common lizard basking.
© James Lindsey/Wikimedia
In two recent papers Tania Rodríguez-Díaz of the Universidad de Oviedo, Spain and colleagues have examined the impact of incubation temperature on the young of the Viviparous Lizard, Zootoca vivipara, and the impact of egg retention on the timing of egg laying.

Rodríguez-Díaz et al. (2010) studied variations in the temperature selected by gravid females compared with those selected by males and non-gravid females of Zootoca vivipara of Northern Spain as well as the impact of incubation temperature on the hatchlings. They found cloacal temperatures of gravid females active in the field were lower than those of males and non-gravid females, as well as the temperatures selected in a thermal gradient created in the laboratory (32°C for gravid females; 34°C for males and non-gravid females). Effects of temperature were assessed by incubating eggs at five constant temperatures between 21 and 34°C. The incubation temperatures affected the hatchlings’ morphology and survival rates. Hatchlings incubated at 34 °C had shorter heads than those from other temperatures; and they had lower survival (58%), significantly lower than at the other temperature treatments (mean 93%). Gravid females select lower body temperatures, as might be expected based on the predictions made by the maternal manipulation hypothesis. The shift in preferred temperature by pregnant females would result in only a very short delay, if any, of hatching time and, because the temperature selected by pregnant females is much higher than average temperatures recorded in natural nests. Retaining eggs shortens incubation time, according to predictions of the cold-climate hypothesis and the authors’ found their experiments with the Viviparous Lizard were in agreement with both the maternal manipulation hypothesis and the cold climate hypothesis.

In a second paper, Rodríguez-Díaz and Braña (2011) investigated the Viviparous Lizard’s ability to retain eggs. Female Z. vivipara were forced to retain their eggs by keeping them on dry substrates. They then assessed the effects on embryonic development, hatching success, offspring phenotype, and locomotor performance. Forced egg retention for the additional week affected the developmental stage of embryos at egg laying, as well as hatchling robustness, and locomotor performance. Embryos from forced clutch retention treatment reached one level of development beyond control embryos at oviposition time. Embryos from control eggs were more developed than embryos from experimental eggs after approximately the same period of external incubation, showing that embryonic development is retarded during the period of extended egg retention, despite the high temperature inside the mother's body. The experimental group with forced egg retention had lower hatching success (21.1%) than in the control group (95.4%).

The results suggest retaining eggs interferes with development, and that simply retaining eggs for longer periods of time does not represent a clear advantage to offspring (or their mothers). However, females that can retain eggs during unfavorable climatic conditions can be successful and doing so may be an important step in the transition to live birth.

Literature
Rodríguez-Díaz, T., F. González, X. Ji and F. Braña. 2010. Effects of incubation temperature on hatchling phenotypes in an oviparous lizard with prolonged egg retention: are the two main hypotheses on the evolution of viviparity compatible? Zoology 113:233-38.
                                              
Rodríguez-Díaz, T., F. and F. Braña. 2011. Plasticity and limitations of extended egg retention in oviparous Zootoca vivipara (Reptilia: Lacertidae). Biological Journal of the Linnean Society 102:75–82.


Thursday, January 13, 2011

Eodromaeus An Early Predator from Argentina


New predator “dawn runner” discovered in early dinosaur graveyard

A team of paleontologists and geologists from Argentina and the United States on Jan. 13 announced the discovery of a lanky dinosaur that roamed South America in search of prey as the age of dinosaurs began, approximately 230 million years ago.

Sporting a long neck and tail and weighing only 10 to 15 pounds, the new dinosaur has been named Eodromaeus, the “dawn runner.”

“It really is the earliest look we have at the long line of meat eaters that would ultimately culminate in Tyrannosaurus rex near the end of the dinosaur era,” said Paul Sereno, University of Chicago paleontologist and National Geographic Explorer-in-Residence. “Who could foretell what evolution had in store for the descendants of this pint-sized, fleet-footed predator?”

Sereno and his colleagues describe a near-complete skeleton of the new species, based on the rare discovery of two individuals found side-by-side, in the Jan. 14, 2011 issue of the journal Science. The paper presents a new snapshot of the dawn of the dinosaur era—a key period that has garnered less attention than the dinosaurs’ demise. “It’s more complex than some had supposed,” Sereno said. 

Set in picturesque foothills of the Andes, the site of discovery is known as the “Valley of the Moon,” said the report’s lead author, Ricardo Martinez of Argentina’s National University of San Juan. For dinosaur paleontologists, it is like no other.

“Two generations of field work have generated the single best view we have of the birth of the dinosaurs,” Martinez said. “With a hike across the valley, you literally walk over the graveyard of the earliest dinosaurs to a time when they ultimately dominate.”

The area was once a rift valley in the southwest corner of the supercontinent Pangaea. Sediments covered skeletons over a period of five million years, eventually accumulating a thickness of more than 2,000 feet (700 meters).

Volcanoes associated with the nascent Andes Mountains occasionally spewed volcanic ash into the valley, allowing the team to use radioactive elements in the ash layers to determine the age of the sediments.
“Radioisotopes—our clocks in the rocks—not only placed the new species in time, about 230 million years ago, but also gave us perspective on the development of this key valley,” said Paul Renne, director of the Berkeley Geochronology Center in California. “About five million years of time are represented in these layers, from one end to the other.”

In the oldest rocks Eodromaeus lived alongside Eoraptor, a similar-sized, plant-eating dinosaur that Sereno and colleagues discovered in the valley in 1991. Eoraptor’s descendants would eventually include the giant, long-necked sauropods. Eodromaeus, with stabbing canine teeth and sharp-clawed grasping hands, is the pint-sized precursor to later meat-eaters called theropods, and eventually to birds. “We’re looking at a snapshot of early dinosaur life. Their storied evolutionary careers are just unfolding, but at this point they’re actually quite similar,” Sereno said.

Eodromaeus at the root of the dinosaur family tree
Vexing scientific questions at the dawn of the dinosaur era include what gave them an edge over competitors, and how quickly did they rise to dominance? In Eodromaeus’ day, other kinds of reptiles outnumbered dinosaurs, such as squat lizard-like rhynchosaurs and mammal-like reptiles. The authors logged thousands of fossils unearthed in the valley to find, as Martinez remarked, that “dinosaurs took their sweet time to dominate the scene.” Their competitors dropped out sequentially over several million years, not at a single horizon in the valley.

In the red cliffs on the far side of the valley, larger plant- and meat-eating dinosaurs had evolved many times the size of Eoraptor and Eodromaeus, but it would be even later when they dominated all land habitats in the succeeding Jurassic and Cretaceous periods.

“The story from this valley suggests that there was no single advantage or lucky break for dinosaurs but rather a long period of evolutionary experimentation in the shadow of other groups,” Sereno said. Other researchers on the paper tracked climate change and other conditions across the layers of the valley. “The dawn of the age of dinosaurs,” Martinez remarked, “is coming into focus.”

Citation
Martinez, R. N., P. C. Sereno, O. A. Alcober, C. E. Colombi, P. R. Renne, I. P. Montañez, B. S. Currie. A Basal Dinosaur from the Dawn of the Dinosaur Era in Southwestern Pangaea. Science, 2011; 331 (6014): 206-210 DOI: 10.1126/science.1198467