Sunday, September 29, 2013

Evidence for a Triassic origin for Lepidosauria


Top: Vellberg jaw. Bottom: restoration image.
 Illustration Credit: Marc Jones.
Two new fossil jaws discovered in Vellberg, Germany provide the first direct evidence that the ancestors of lizards, snakes and tuatara (known collectively as lepidosaurs) were alive during the Middle Triassic period -- around 240 million years ago.

The new fossil finds predate all other lepidosaur records by 12 million years. The findings are published in BMC Evolutionary Biology.

The international team of scientists who dated the fossil jaws have provided evidence that lepidosaurs first appeared after the end-Permian mass extinction event, a period when fauna began to recover and thrive in the more humid climate.

Lead author Dr Marc Jones, who conducted the research at UCL, explained: "The Middle Triassic represents a time when the world has recovered from the Permian mass extinction but is not yet dominated by dinosaurs. This is also when familiar groups, such as frogs and lizards, may have first appeared."
The small teeth and lightly built jaws suggest that the extinct animal preyed on small insects. The new fossils are most closely related to the tuatara, a lizard-like reptile.

Tuatara can be found on 35 islands lying off the coast of New Zealand and were recently reintroduced to the mainland. However, they are the sole survivors of a group that was once as globally widespread as lizards are today. Tuatara feed on beetles, spiders, crickets and small lizards, also enjoying the occasional sea bird.
Today, there are over 9,000 species of lizards, snakes and tuatara. Knowing when the common ancestor of this grouping first appeared is crucial for understanding the ecological context in which it first evolved as well as its subsequent diversification.

To establish the age of the fossil remains, biologists use a dating technique known as a "molecular clock." This method compares the amount of genetic divergence between living animals, caused by changes in their DNA sequences that have accumulated since they split from a common ancestor. These mutations occur fairly regularly, ticking along at a clock-like rate. However, for the clock to convert genetic differences into geological time, it has to be calibrated using one or more fossils of known relationship and time.

Molecular clocks have been used by biologists to answer questions as important as when the first modern humans emerged, and when humans and chimpanzees shared a common ancestor. The new fossil jaws can improve molecular dating estimates of when reptiles began to diversify into snakes, lizard and tuatara, and when the first modern lizards inhabited the earth. Previous estimates have varied over a range of 64 million years and the team are keen to help narrow this down.

"Some previous estimates based on molecular data suggested that lizards first evolved 290 million years ago," said second author Cajsa Lisa Anderson, University of Gothenburg. "To a palaeontologist this seems way too old and our revised molecular analysis agrees with the fossils."

Revised molecular dating in light of this new fossil find now suggests lizards began to diversify into most of the modern groups we recognize today, such as geckos and skinks, less than 150 million years ago in the Cretaceous period, following continental fragmentation.

The specimens were collected and initially identified by Professor Rainer Schoch from the Staatliches Museum für Naturkunde in Stuttgart, where the specimens are now registered.

Scientists anticipate that the Vellberg site will yield yet more fossil discoveries in the future, broadening our knowledge of the vertebrate fossil record.

Co-Author Professor Susan Evans, from the UCL Department of Cell and Developmental Biology, said: "The fossil record of small animals such as lizards and frogs is very patchy. Hopefully, this new fossil site in Germany will eventually give us a broader understanding of what was going on at this time."

Citation

Jones MEA, Aderson L, Hipsley CA, Müller J, Evans SE,  Schoch RR. 2013. Integration of molecules and new fossils supports a Triassic origin for Lepidosauria (lizards, snakes, and tuatara). BMC Evolutionary Biology, 13 (1): 208 DOI: 10.1186/1471-2148-13-208

The Second Trinidad Buioblitz

The second annual Trinidad Bioblitz has come and gone.  This year it was held in the very biodiverese Arima Valley, with the base camp at the Asa Wright Nature Center. The preliminary tally of species was - Vertebrates 139, Invertebrates 247, Fungus 30, Diatoms 7, Plants 317 for a grand total of 740 species!

Teams include: Mammals, Freshwater (Fish, Aquatic Insects, Crustaceans), Amphibia and Reptilia, Birds, Molluscs, Spiders and other Arachnids, Butterflies and Moths, Social Insects, Myriapods millipedes/ centipedes) and Worms, Flowering Plants, Ferns, Lichens, Orchids and Fungi.

The Arima Valley has been the crown jewel for Trinidad's biodiversity for centuries, the site has been the geographical location for much of the scientific research that has occurred on Trinidad including classic studies of bats, guppies, and the herpetofauna as well as many other higher taxa. However, active quarrying operations threaten the habitat, and the activity of bush meat hunters threaten larger animal populations. But, perhaps the most significant sign that the valley is under development - the installation of sidewalks along the road.

But, the Bioblitz results suggest the flora and fauna are doing well at least for the moment. Teams of experts and volunteers  searched the valley for 24 hours attempting to identify as many species as possible. But, it can be more than just a list, because the opportunity of natural history observations is under every log and in every fruiting tree.

 Informational displays by various groups including the Trinidad and Tobago Field Naturalist Club, UWI Zoology Museum, Asa Wright Nature Center and Wildlife Division were present to  inform the public. So what about the herpetofauana. Here are some photos of what was found.

An Arima Valley Bothrops cf asper. was sitting in the vegetation close to a
 chorus of Hypsiboans crepitans.
Top: a juvenile Chironius carinatus, bottom Chironius (Macrops)
septentrionalis. Both juveniles and very difficult to distinguish
from each other, but look at the relative size of the eyes

Hypisboans crepitans hiding in the vegetation during the day.

Epictia tenella was found climbing a tree trunk, it was about a meter
off the ground and was probably headed for a rotten liana filled with
termites.

A juvenile Oxyrhopus petolarius

Anolis planiceps sleeping on a leaf.

A male Gonatodoes vittatus perhaps the most common seen
reptile during the Bioblitz
The leaf-nesting frog, Phyllomedusa trinitatus



Friday, September 13, 2013

Suzio Report, Summer Fun

Howdy Herpers,                                                         9/12/13

Well friends, it has been too long since Typing Boy here has addressed you. I trust that the lack of reports lately has not caused too much angst in your lives?

So much has happened since Marty found that little tortoise in the black widow spider web that I hardly know where to begin. I do know that this had better be good, and my face now retains the red marks of a severe bitch-slapping from my own hand. There are 2600 reasons to shine now. Wake up and address these people, Roger! And make it count. Dammit!

As some of you know, the Herp Accountant here has been keeping close tabs on every turtle, snake, and lizard that he encounters. In some cases, the counts go back to 1989. But the common lizard numbers did not begin in earnest until the year 2000. It is that 12 plus year time period, along with the common lizards, that are going to be discussed next.

While every herp found is enshrined in my hallowed herp journal, there are really only six species of lizard that I consider indicators of how good or bad a herp year is. Experience has taught me that these wiggly little suckers, to varying degrees, are the herps that clearly demonstrate how good or bad a year can be.  Without further adieu, these six species are Zebra-tailed Lizards, Side-blotched Lizards, Whiptails, Desert Spiny Lizards, Regal Horned Lizards, and, of course, Gila Monsters. There is another number that plays as a wild card in my judgment of a herp year. That is the total number of lizards encountered.

The same system is used on snakes and turtles. We are not going to talk all that much on these except for one thing: 2013 is heading toward the worst herp year that I’ve ever had for snakes. At the end of August, 160 snakes were logged. My worst snake year ever was 221, and that was in 2002. Unless things pick up mightily, the lamenting in the year-end report for the Tucson Herpetological Society Journal is going to be impressive in both content and duration. (And if you want to see that report, you will have to become a member of the THS. Cough up your 20 bucks, pikers!).

Now that we have discussed what is bad in 2013, can we move on to the good? Great! Let’s mow these lizards down in order. For the Zebra-tailed Lizards, my best year of the century was 1,519. That was in 2008. With two months of possible encounters remaining, (they shut down by early November), the number for 2013 is 1,398. Already, 2013 is the second best year of the century. Will we beat 2008? Time will tell! With the Side-blotched Lizards, unless hordes of them suddenly rain down upon us, we will wind up with only slightly above average numbers. No big deal. Their best use is conversion to Lyresnake mass. Hopefully, that’s where they all went this year. We’re done with the likes of them. With the Whiptails, (several species), we have already broken the record set last year. That number was 453. We are now at 575! In 2008, I encountered 137 Desert Spiny Lizards. The count for these chunky fat heads is currently 108, which is 35 above average over the time period under discussion. Again in 2008, 20 Regal Horned Lizards were found which I crowed mightily about at the time. In 2013, the number now stands at 23, with more incoming expected. This is a record-breaker for one of the lizards that I love most! Last year, a record number of 32 Gila Monsters were encountered. At this point in 2013, we are at 25. We are already at the third best year of the century with these numbers, and again, more incoming is expected. Last, but not least, the wild card. Again, in 2008, the all species of lizard count was 2,978. This year, we are at 3,043! If we did not see one more stinking lizard for the remainder of the year, we are still walking in tall cotton.

We will stop with this type of herpetological bean-counter talk here, and move on to the hard-wired snakes under watch in paradise. Before my emailed leg-hump of late, we had 14 different rattlesnakes under watch, and were facing the prospect of cutting some of those out of the game. Thanks to what I am now calling the 2600 club, our N is now 17. And we expect to bump that to 20 by the end of this month. Yes sirs and madams, 20 transmitters will soon be merrily blipping across a swath of remote Sonoran Desert Thornscrub 2 kilometers long by 1 kilometer wide. When we fire up those receivers, we will not know whether to defecate, or go blind. This is called “fun.”  The thrill of mowing down 20 rattlesnakes whilst hoofing through a sticker-infested wonderland is mother’s milk to the few, the proud, the geeks! Thanks guys! And come on out to play with us sometime………

As much as Typing Boy would like to show you each and every snake that we have out there now, that is not possible. Truth be told, some of the newer snakes have yet to reveal themselves for good, in situ images. A case in point is our newest snake, CA134, a young male atrox. We released him on the evening of 31 August. I did not track him for the first time until 7 September. His signal was coming from the center of a flat, heart-shaped slab of gneiss. When I looked into the soil entrance, I saw two large adults looking back out at me. CA134 was behind these two­ no doubt stuck until they decide to leave. Right off the bat, he leads us to a mini aggregation. Sensational!  

Until now, I have made no mention of a little sweetheart of a female molossus that is under watch. She is CM18, as yet un-named. She is just shy of 2 feet long, and her rattle count is basal, 4 segments, and a button. Marty found her hanging out with our pregnant molossus CM17. Mother, daughter? Time will tell, I just hope that the DNA gets processed in my lifetime so that we will know for sure. The first image in this report is of her. We released her on 10 August, and with the first tracking on 14 August, she has scored a meal. Bully for her!

Speaking of scoring meals, Mr. Feldner was blessed to observe, and subsequently photograph, our female tiger CT13 track down and consume a pocket mouse. See image number 2. Following her feast, she moved from the flats to the top of Iron Mine Hill. A fattened female will draw in males quicker than flies on feces. Like a jack rabbit on a hot date, our male tiger, CT11, made a major move of over 300 meters to join her. And on the evening of 7 September, lucky Marty and John Slone found the pair in full coitus. See image 3. While we were blessed to see five pairings last year, this is the first mating event with tigers that we have ever witnessed. We’re moving on up!

I’ve tossed a hodge-podge of images into this report. They’re all labeled, so that you will know who is who and when. Look for a full screen view of a cluster of three barrel cacti. Where’s Waldo? The next image reveals him. Look for two images of a tortoise. The first shows the surreal backdrop of a Sonoran Desert, and the second pulls the rear of the tortoise into view. Look carefully at the rear vertebral scute. That is what is left of a license plate that was affixed to his shell in 2005. It took that rascal eight years to finally wear off. Nice job, Josh! Check out the nice string of rattles on CT14. This snake in particular is still in the game for another year, thanks to the 2600 club. He was on the bubble prior to your generosity. He is probably less grateful than we are about the prospect, but there is no allowance for poop socks on our turf. 

The second to the last image is a teaser for you. You won’t have to look too hard to see that there is more than one snake in that image. By June, despite assurances from Dr. DeNardo that CM10, “Susan,” had six neonates in her ovaries, we had determined that Susan was not pregnant. The night that this photo was taken, I was still under the notion that she was not pregnant. I was correct! It was not until 10 days after this image was taken that the two neonates were discovered.



























Everybody ought to carry a camera. They come in handy sometimes! Our next report will center on matters of fecundity in paradise. For now:

This here is Roger Repp, signing off from Southern Arizona, where the turtles are strong, the snakes are handsome, and the lizards are ALL above average. It is a place where every meal is a banquet, every sunrise is an event, and every sunset brings the promise of good things lying ahead. 


Thursday, September 12, 2013

Rhacophorid frog phylogeny on Borneo

Kurixalus appendiculatus
Rhacophoridae is a major clade of Afro-Asian tree frogs, that has radiated into many different niches. Rhacophorids contribute significantly to the high species richness and reproductive diversity of Sundaland vertebrates. Nonetheless, rhacophorid evolution, especially on Borneo, has not been studied within a phylogenetic context. In a new study Hertwig et al. examine the phylogenetic relationships of 38 (of 41 known) Bornean  rhacophorid frogs, in combination with data from previous phylogenetic studies. In the final super matrix of 91 species, they analyse sequence data from two mitochondrial and three nuclear genes. The results show the genus Rhacophorus as a paraphyletic  assemblage. Consequently they transfer Rhacophorus appendiculatus and R. kajau to two other genera and propose the new phylogeny-based combinations- Kurixalus appendiculatus and Feihyla kajau, respectively. Surprisingly they also found Theloderma moloch, a northeast Indian species, is an independent lineage of frogs within the  rhacphorid clade, separate from the other species of Theloderma (asperum, corticale, and rhododiscus) in the study. They also use their phylogenetic hypotheses to reconstruct the evolution of reproductive modes in rhacophorid tree frogs. Direct development to the exclusion of a free larval stage evolved twice independently, once in an ancestor of the Pseudophilautus + Raorchestes clade in India and Sri Lanka, and once within Philautus in Southeast Asia. The deposition of egg clutches covered by a layer of jelly in Feihyla is also present in F. kajau and thus confirms its generic reassignment. The remarkably high diversity of rhacophorid tree frogs on Borneo is the outcome of a complex pattern of repeated vicariance and dispersal events caused by past changes in the climatic and geological history of the Sunda shelf. The authors also identified geographic clades of closely related endemic species within Rhacophorus and Philautus, which result from local island radiations on Borneo.

Citation
Hertwig ST,  Schweizer M, Das I, Haas A. 2013. Diversification in a biodiversity hotspot – The evolution of Southeast Asian rhacophorid tree frogs on Borneo (Amphibia: Anura: Rhacophoridae). Molecular Phylogenetics and Evolution 68: 567–581.

Tuesday, September 3, 2013

The record-sized alligator


The major news outlets are carrying the story of Dustin Brockman of Vicksburg, Mississippi who, with his brother and friend, killed a 727-pound record breaking alligator that was 13 feet, 4.5 inches long. The previous weight record was 697.5 pounds, according to a Mississippi Department of Wildlife, Fisheries, program coordinator.

Brockman is quoted as saying, “We chased him for about two hours, ...Then we got a shot on him.” The alligator was shot with a crossbow before they could shoot it with a shotgun. It took four hours to get the gator into the boat, it was too heavy for the three men to handle so they just waited in the middle of the river for the sun to rise. At 6:30 (a.m.) Brockman called three or four more guys to help load the alligator into the boat.

Just an hour prior to the Brockman catch, another hunting party led by Beth Trammell of Madison, Mississippi hooked a 13-foot, 5.5-inch alligator near Redwood. The Trammell party's alligator broke the previous weight record with their 723.5-pound catch until Brockman broke it 60 minutes later.

According to the media the current length record  has yet to be broken, is 13 feet, 6.5 inches. That alligator was captured on the Pascagoula River in 2008, according to the Mississippi Wildlife, Fisheries and Parks department.

Now, these are certain large animals. But neither qualifies as the record size alligator. In fact, neither iseven close to being the record sized alligator. Edward Avery Mc lLHenny's 1935 book, The Alligator's Life History is a natural history classic. Mc lLHenny's  describes the alligator's voice, hibernation habits, den construction, feeding habits, reproduction, growth, predation and other aspects of alligator life history in great detail.  All of which has been subsequently verified by 20th century crocodilian biologists. Mc lLHenny's  lived on Avery Island, Louisiana and became a prominent conservationist and wildlife advocate. 

On page 59 of his book, Mc lLHenny's  writes,


"There is plenty of evidence in the written record of long past observers that alligators in Louisiana attain an extreme length of, at least eighteen or twenty feet. To my certain knowledge, there has been taken in the vicinity of Avery island, three alligators exceeding eighteen feet in length. One of these was an alligator known to we boys as "Monsurat," killed by Mr. Robert Mooney at Avery Island in 1879, which was measured by my father. This alligator was eighteen feet, three inches in length. The next large one that I remember seeing measured, was killed by Robert Dell, our plantation overseer, in October, 1882, at the junction of the road across the marsh joining Avery Island with the mainland, at the Avery Island end. Dell was coming in over the road and saw this alligator crossing the road. He had a pistol with him, and shot the alligator from his horse, killing it. On his describing its size to my father and uncles, a four-mule team and wagon was sent to bring it to our house. This alligator measured eighteen feet, five and one-half inches."

He continues with a description of an alligator he killed and measured on January 2, 1890  in a small bayou that connected lake Cock with Vermilion Bay (LA). The animal measured 19 feet 2 inches. This is the record generally accepted by herpetologists for the largest Alligator mississippiensis.

Citation
MclLHenny, E. A. 1935. The Alligator's Life History.The Christopher Publishing House, Boston. 117 pp.




Thursday, August 29, 2013

Diet overlap in aquatic snake assemblages

Competition for prey is thought to be important in structuring snake assemblages. However, given the secretive behavior and low detectability of many snake species, this generalization is based on a limited number of studies, most of which focus on a single study site. In a forthcoming paper in the Journal of Zoology Durso et al (2013) examined differences in diet composition, trophic niche overlap, site occupancy and detectability of five sympatric aquatic snake species [eastern mud snake, Farancia abacura; banded watersnake, Nerodia fasciata; Florida green water snakes, N. floridana; glossy crayfish snakes, Regina rigida; and black swamp snakes, Seminatrix pygaea] between two different habitat types in the southeastern US. They studies  permanent wetlands with fishes (n = 13) and isolated, often ephemeral wetlands without fishes (n = 10). More than 3700 prey items were collected from snakes and compared diet composition among snake species to examine niche breadth and overlap, correcting for relative availability of prey captured independently in the same wetlands. They also evaluated evidence for competitive exclusion by estimating the probability of co-occupancy for pairs of snake species in each habitat type using occupancy modeling. In wetlands with fishes, niche overlap was low, suggesting resource partitioning. Conversely, in wetlands without fishes, niche overlap was high, with most species feeding on larval or paedomorphic ambystomatid salamanders, but competitive exclusion did not occur. They suggest that high co-occupancy of aquatic snakes in wetlands without fishes, despite the apparent lack of resource partitioning, is due to a combination of seasonally high abundance of high quality amphibian prey, unique aspects of predator physiology and stochastic abiotic processes that prevent these systems from reaching equilibrium. The results demonstrate that snake diets can be highly context (e.g. habitat) specific.

Citation
Durso AM, Willson J D, & Winne CT. (2013)  Habitat influences diet overlap in aquatic snake assemblages. Journal of Zoology. DOI: 10.1111/jzo.12061

Social female copperheads found to be non-kin

Recent observations suggest snakes may be far more social than previously thought, including the ability to recognize and group with kin, and provide parental care (defense) for young. Inclusive fitness theory predicts that benefits of such groupings should be greater when groups are composed of related individuals. Although the ability required to recognize kin under this theory has been observed in a wide range of vertebrates, it has only recently been reported in snakes. Li et al. (2013) tested competing hypotheses for aggregation behavior in female neonate copperhead snakes, female aggregations are common in nature; male aggregations have not been observed.  They asked is (1) aggregation is mediated by genetic relatedness, or is (2) aggregation is mediated by familiarity, i.e. learned. The authors found no effect of learning on neonate aggregation. With regard to relatedness, contrary to  expectation they found  unrelated individuals tended to aggregate more than related individuals. The authors suggest that the lack of aggregation behavior in related individuals may be due to selection for dispersal and/or reduced effects of predation or disease.

Citation
Li M., Moeller JF,  Smith CF. (2013). Family and Friends: What Factors Influence Aggregation in Female Copperhead Snakes?. Lander University 9: 15-9: 27.

Monday, August 26, 2013

Eastern coral snake venom found to contain molecules from 15 toxin families

Snake venom is shaped by the ecology and evolution of the species that makes it. Evidence of positive selection in toxins have been consistently documented, reflecting the role of venoms as an ecologically critical phenotype. New World coral snakes (Elapidae) are represented by three genera and over 120 species and subspecies that are capable of causing significant human morbidity and mortality, yet coral-snake venom composition is poorly understood in comparison to that of Old World elapids.

In a recently published article Mark Margres of Florida State University and colleagues used high-throughput sequencing to identify thousands of loci, while providing characterizations of expression patterns and the molecular evolutionary forces acting within the venom gland.

The authors describe the de novo assembly and analysis of the venom-gland transcriptome of the eastern coral snake (Micrurus fulvius). The identified 1,950 nontoxin transcripts and 116 toxin transcripts. These transcripts accounted for 57.1% of the total reads, with toxins accounting for 45.8% of the total reads. Phospholipases A2 and three-finger toxins dominated expression, accounting for 86.0% of the toxin reads. A total of 15 toxin families were identified, revealing venom complexity previously unknown from New World coral snakes. Toxins exhibited high levels of heterozygosity relative to nontoxins, and overdominance may favor gene duplication leading to the fixation of advantageous alleles. Phospholipase A2 expression was uniformly distributed throughout the class while three-finger toxin expression was dominated by a handful of transcripts, and phylogenetic analyses indicate that toxin divergence may have occurred following speciation. Positive selection was detected in three of the four most diverse toxin classes, suggesting that venom diversification is driven by recurrent directional selection.

The new research describe the most complete characterization of an elapid venom gland to date. Toxin gene duplication may be driven by heterozygote advantage, as the frequency of polymorphic toxin loci was significantly higher than that of nontoxins. Diversification among toxins appeared to follow speciation reflecting species-specific adaptation, and this divergence may be directly related to dietary shifts and is suggestive of a co-evolutionary arms race.


Citation
Margres MJ, Aronow K, Loyacano J, Rokyta DR 2013.The venom-gland transcriptome of the eastern coral snake (Micrurus fulvius) reveals high venom complexity in the intragenomic evolution of venoms. BMC Genomics 2013, 14:531.

Saturday, August 17, 2013

Female mate choice in Hyla chrysoscelis

From frogs to humans, selecting a mate is complicated.  Females of many species judge suitors based on many indicators of health or parenting potential. But it can be difficult for males to produce multiple signals that demonstrate these qualities simultaneously.

In a study of gray tree frogs, a team of University of Minnesota researchers discovered that females prefer males whose calls reflect the ability to multitask effectively.  In this species (Hyla chrysoscelis) males produce "trilled" mating calls that consist of a string of pulses.

Typical calls can range in duration from 20-40 pulses per call and occur between 5-15 calls per minute. Males face a trade-off between call duration and call rate, but females preferred calls that are longer and more frequent, which is no simple task.

The findings were published in August issue of Animal Behavior.

"It’s kind of like singing and dancing at the same time," says Jessica Ward, a postdoctoral researcher who is lead author for the study. Ward works in the laboratory of Mark Bee, a professor in the College of Biological Sciences’ Department of Ecology, Evolution and Behavior.

The study supports the multitasking hypothesis, which suggests that females prefer males who can do two or more hard-to-do things at the same time because these are especially good quality males, Ward says.  The hypothesis, which explores how multiple signals produced by males influence female behavior, is a new area of interest in animal behavior research.

By listening to recordings of 1,000 calls, Ward and colleagues learned that males are indeed forced to trade off call duration and call rate. That is, males that produce relatively longer calls only do so at relatively slower rates.

"It's easy to imagine that we humans might also prefer multitasking partners, such as someone who can successfully earn a good income, cook dinner, manage the finances and get the kids to soccer practice on time."

The study was carried out in connection with Bee’s research goal, which is understanding how female frogs are able to distinguish individual mating calls from a large chorus of males. By comparison, humans, especially as we age, lose the ability to distinguish individual voices in a crowd. This phenomenon, called the "cocktail party" problem, is often the first sign of a diminishing ability to hear. Understanding how frogs hear could lead to improved hearing aids.

College of Biological Sciences faculty conduct research in all areas of biology, from molecules to ecosystems, which supports applications in medicine, renewable energy, agriculture and biotechnology. The college offers degree programs in biochemistry, molecular biology and biophysics; genetics, cell biology and development; ecology, evolution and (animal) behavior; plant biology; microbiology and neurosciences. Admission to undergraduate programs is highly competitive.

Citation
Ward JL, Love EK, Vélez A, Buerkle NP, O'Bryan LR, Bee MA. 2013. Multitasking males and multiplicative females: dynamic signalling and receiver preferences in Cope's grey treefrog. Animal Behaviour, 2013; 86(2):231 DOI: 10.1016/j.anbehav.2013.05.016

Thursday, August 15, 2013

Sea snakes disappear at Ashmore Reef despite protection


The Ashmore Reef National Nature Reserve was established in 1983 and covers 583 kmAshmore Reef  contains seagrass beds, intertidal sand flats, coral reef flats, and lagoons, and supports an important and diverse range of species, including 14 species of sea snakes, a population of dugong that may be genetically distinct, a diverse marine invertebrate fauna, and many endemic species, especially of sea snakes and molluscs. Feeding and nesting sites for loggerhead, hawksbill and green turtles are present. And, it is an Important Bird Area with 50,000 breeding pairs of seabirds.

Malcolm Smith recognized the high diversity and abundance of  sea snakes in his  1926 Monograph of Sea Snakes. In 1973  Alpha Helix expedition collected more than 350 sea snakes representing nine species in less than two weeks and observed many more In 2005 the  standing stock of sea snakes was estimated at about 40,000  snakes on the 174 kmreef flat of Ashmore Reef.

Besides high species diversity and abundance, there are high levels of sea snake endemism at Ashmore Reef. Half of the species (3/6) from the Aipysurus lineage recorded from Ashmore Reef are restricted to the Timor Sea. Endemics that almost certainly evolved in the Timor Sea highlighting the  role this region has played in the evolutionary history of the Aipysurus lineage. Additionally four of the nine resident species and three of the five vagrant species are Australasian endemics.

In a new study, Lukoschek et al. (2013) report on surveys conducted between 1973 and 2010. They recorded the highest abundances (average 42–46 snakes day)  and species richness (nine species) in 1973 and 1994. In 2002 abundance had declined by more than 50% (21 snakes day) and only five species were recorded. Since 2005 abundances have been consistently low (1–7 snakes per day) with just two species, Aipysurus laevis and Emydocephalus annulatus, recorded in significant numbers. Extensive searches since 2005 (especially in 2010) five species of sea snake historically abundant at Ashmore Reef have not been observed and are presumed  locally extinct. These species include three Timor Sea endemics Aipysurus apraefrontalis, Aipysurus foliosquama, Aipysurus fuscus, and one Australasian endemic Aipysurus duboisii. Declines in sea snake abundance and diversity at Ashmore Reef cannot be attributed to differences in survey methods over time.

The authors discuss habitat loss, illegal harvesting, decline in prey, disease, invasive species, and pollution as possible causes for the decline. But it is important to note the declines happened in spite of Ashmore Reef's National Nature Reserve (IUCN Category 1a) status that was declared in 1983 and, although the causes for the declines are not known, this protection has not prevented their disappearance.

Citation
Lukoschek V, Beger M, Ceccarelli  D,  Richards Z,  Pratchett M, 2013. Enigmatic declines of Australia’s sea snakes from a biodiversity hotspot, Biological Conservation, 166, 191-202, ISSN 0006-3207,

Tuesday, August 6, 2013

The beaded lizard reassed

The beaded lizard (Heloderma horridum) has a fragmented distribution in Mesoamerica that extends from northwestern Mexico to eastern Guatemala.  Locally known as the “escorpión” its natural history is surrounded by mystery, notoriety and misconception. Consequently, it is frequently slaughtered when encountered. Adding to this anthropogenic pressure, beaded lizard populations, with rare exceptions  occur primarily in seasonally dry tropical forests,  the most endangered biome in Mesoamerica owing to persistent deforestation for agriculture, cattle ranching, and a burgeoning human population. Drought and fires escalate the above threats and recent predictive models of climate change suggest  persistence of seasonally dry tropical forests in this region is highly dubious.

Despite its large size and charismatic nature, knowledge of the ecology, geographic distribution, and status of beaded lizard populations remains limited.

Reiserer et al. (2013) reassess the taxonomic status of the beaded lizard populations using morphology, biogeography, and a recent molecular-based analysis conducted by Douglas et al. (2010).

The authors found the greatest divergence between H. h. charlesbogerti and H. h. exasperatum (9.8%), and the least between H. h. alvarezi and H. h. charlesbogerti (1%). The former clade represents populations that are widely separated in distribution (eastern Guatemala vs. southern Sonora, Mexico), while  in the latter clade the populations are much closer (eastern Guatemala vs. Chiapas, Mexico). The nominate subspecies (Heloderma h. horridum) differed from the other subspecies of H. horridum by 5.4% to 7.1%.

The new study suggests beaded lizards diverged from a most-recent common ancestor about 35 million years ago in the Late Eocene, and subsequent diversification occurred during the late Miocene (9.71 mya), followed by a lengthy stasis of up to five million years, more recent diversification  extended into the Pliocene and Pleistocene. In both beaded lizards and seasonally dry tropical forests, the tempo of evolution and diversification was uneven, and their current distributions are fragmented. Based on multiple lines of evidence, including a review of the use of trinomials in taxonomy, the authors elevated the four subspecies of beaded lizards to full species: Heloderma alvarezi (Chiapan beaded lizard), H. charlesbogerti (Guatemalan beaded lizard), H. exasperatum (Río Fuerte beaded lizard), and H. horridum (Mexican beaded lizard), with no changes in their vernacular names. The full article is available on-online.

Citations
Reiserer RS, Schuett GW, Beck DD. 2013. Taxonomic reassessment and conservation status of the beaded lizard, Heloderma horridum (Squamata: Helodermatidae). Amphibian & Reptile Conservation 7(1): 74–96.

Douglas ME, Douglas MR, Schuett GW, Beck DD, Sullivan BK. 2010. Conservation phylogenetics of helodermatid lizards using multiple molecular markers and a supertree approach. Molecular Phylogenetics and Evolution 55: 153–167.

Friday, August 2, 2013

A second specimen of the bush viper, Atheris hirsuta

 Atheris hirsuta
The viper, Atheris hirsuta was described by Ernst & Rödel in  2002, based on a single specimen found near the ecological research station in the Taï National Park, Côte d’Ivoire. The holotype was found in secondary rainforest between a field station and the town of Taï. It was collected on a dirt road during heavy rain, however, it is clearly adapted to an arboreal lifestyle.

Recently a short survey of the herpetofauna of Mt. Swa in Nimba County, Liberia (~200 km west of the type locality) revealed a second specimen of this species. The mountain does harbour good secondary forests and altitude stays below 600 m above seal level. The specimen was found around 2100 h on the 26 September 2012. The individual was observed climbing in secondary vegetation about 2 m above ground on the ridge of the mountain at about 585 m. No water bodies of any kind were found on top of the ridge. Weather was windy, cloudy but without rain.

Tai National Park holds the largest protected rainforest in West Africa. The forest habitat outside the national park is fragmented and being degraded by agricultural and human population expansion. Eventually  these pressures are expected to extend into the national park.

Citation
Penner J,  Gonwouo NL &  Rodel M-O1 2013. Second record of the West African hairy bush viper
Atheris hirsuta Ernst & Rödel, 2002 (Serpentes: Viperidae). Zootaxa 3694 (2): 196–200.

Suizo Report -- Thanks and July 2013

Howdy Herpers,                                                                                                               07/31/13

Thank you cards are slugging their way toward the nine kind souls who gave our fiscal situation a jump start. Thanks to their efforts, we can not only keep the animals in the game that we have, but also add a few more. I do not wish to embarrass anybody by mentioning names here. Just know that when the acks are presented, your names will be enshrined. And that ought to add numerous zeros to your paychecks, open the gates of heaven for you and yours, and massively improve your love lives.

As for the rest of you--see what you missed? But it's never too late!

Ok, enough with the BS.

On the evening of 3 July, Typing Boy here was tracking  our pregnant female CM17. This was one of those rare nights when Marty Feldner was at my side, instead of being on the other side of the hills mowing down a line of snakes. Whenever we track together, Marty lets me track. There is no sense in him doing the tracking, as he'll leave me in his dust. So he happily weaves a herpetological tapestry around me as we move. Typing Boy was following the path of least resistance, following the cattle trails that line the berm of an arroyo that flows from the bowels of a slot canyon. Marty was a couple climate zones above me, when he yells down to me: "Got a hatchling tortoise."

Tortoises of any size will cause a break from tracking, but all the more so for hatchlings. Sluggo made his way upslope to view the find.

Sure enough, once I gave pause to forcibly eject some black lung tissue shaken loose from the arduous climb, I saw Marty's hatchling tortoise.

Its head was up, one foreleg poised as if to take the next step. We both took several photos, marveling over how cooperative the little gogger was being. At some point later, Marty morphed into a poopsock by proclaiming "I think it's dead." Inspired by this statement, I gave it a poke with my walking stick. This did nothing to disturb the status quo, not to mention the tortoise. The poopsock was correct, the little gogger was quite dead.

A couple of strands of spider web were strung across its head, and one of the strands had also snagged its right forelimb. We eventually broke the hapless thing out of the web, noting that the strands had the tensile strength of thin steel wire. There is only one spider that spins webs like that in these parts--the black widow.

The most likely cause of death is that it was merely stuck, and baked its brains out in the sun. There were some signs of trauma to the head, which could have been from a bite. In any case, this event has stumped many a tortoise Jedi. There is more info that could be shared--but I won't.

Marty and I WILL go Hollywood with this observation, and reveal the rest therein. (If I do it here, all chance of a natural history note dies. Why publish it here--where people will actually read it?)

That, my friends, is what image 1 is all about. Cool--huh?

As most of the images are labeled, it makes no sense for me to beat them to death with lengthy descriptions. A few highlights include our newest male tiger CT16 with rain drops on his coiled form, the shed skin of an atrox that looks very much like a living snake, one of the neonate tigers shown in our last missive at its release site, and the face of God closes this missive.














Best to all, roger


Tuesday, July 30, 2013

A novel approach to treating venomous snakebites

SAN FRANCISCO (July 30, 2013) – A team of researchers led by Dr. Matt Lewin of the California Academy of Sciences, in collaboration with the Department of Anesthesia at the University of California, San Francisco, has pioneered a novel approach to treating venomous snakebites—administering antiparalytics topically via a nasal spray. This new, needle-free treatment may dramatically reduce the number of global snakebite fatalities, currently estimated to be as high as 125,000 per year. The team demonstrated the success of the new treatment during a recent experiment conducted at UCSF; their results have been published in the medical journal Clinical Case Reports.

Snakebite is one of the most neglected of tropical diseases—the number of fatalities is comparable to that of AIDS in some developing countries. It has been estimated that 75% of snakebite victims who die do so before they ever reach the hospital, predominantly because there is no easy way to treat them in the field. Antivenoms provide an imperfect solution for a number of reasons—even if the snake has been identified and the corresponding antivenom exists, venomous bites often occur in remote locations far from population centers, and antivenoms are expensive, require refrigeration, and demand significant expertise to administer and manage.

“In addition to being an occupational hazard for field scientists, snakebite is a leading cause of accidental death in the developing world, especially among otherwise healthy young people,” says Lewin, the Director of the Center for Exploration and Travel Health at the California Academy of Sciences. “We are trying to change the way people think about this ancient scourge and persistent modern tragedy by developing an inexpensive, heat-stable, easy-to-use treatment that will at least buy people enough time to get to the hospital for further treatment.”

In his role as Director of the Academy’s Center for Exploration and Travel Health, Lewin prepares field medicine kits for the museum’s scientific expeditions around the world and often accompanies scientists as the expedition doctor. In 2011, Lewin put together snakebite treatment kits for the Academy’s Hearst Philippine Biodiversity Expedition, which would have required scientists to inject themselves if they needed treatment. When he saw their apprehension about the protocol, Lewin began to wonder if there might be an easier way to treat snakebite in the field.

In some fatal snakebites, victims are paralyzed by the snake’s neurotoxins, resulting in death by respiratory failure. A group of common drugs called anticholinesterases have been used for decades to reverse chemically-induced paralysis in operating rooms and, in intravenous form, to treat snakebite when antivenoms are not available or not effective. However, it is difficult to administer intravenous drugs to treat snakebite outside of a hospital, so Lewin began to explore the idea of a different delivery vehicle for these antiparalytics—a nasal spray.

In early April of 2013, Lewin and a team of anesthesiologists, led by Dr. Philip Bickler at UCSF Medical Center, designed and completed a complex experiment that took place at the medical center. During the experiment, a healthy human volunteer was paralyzed, while awake, using a toxin that mimics that of cobras and other snakes that disable their victims by paralysis. The experimental paralysis mimicked the effects of neurotoxic snakebite, progressing from eye muscle weakness all the way to respiratory difficulty, in the same order as is usually seen in envenomation. The team then administered the nasal spray and within 20 minutes the patient had recovered. The results of this experiment were published online in the medical journal, Clinical Case Reports.

Later in April, Lewin delivered one of the keynote addresses, titled “How Expeditions Drive Clinical Research,” at the American Society for Clinical Investigation/Association of American Physicians joint meeting in Chicago, during which he talked about this experiment and its origins. As a result, he met Dr. Stephen Samuel, an Indian physician and scientist from Trinity College Dublin who was interested in collaborating in India, where an estimated 1 million people are bitten by snakes every year, resulting in tens of thousands of deaths. Lewin flew to India to help Samuel set up treatment protocols at a rural hospital in Krishnagiri.

In late June, Samuel, Dr. CS Soundara Raj and colleagues at TCR Multispeciality Hospital in Krishnagiri, Tamil Nadu, India treated a snakebite victim using this method. The patient was suffering from persistent facial paralysis from a krait bite, despite having undergone a full course of antivenom treatment. Upon treatment with the antiparalytic nasal spray, the facial paralysis was reversed within 30 minutes. Two weeks after being treated, the patient reported having returned to her daily activities.

Lewin and his colleagues in the United States are now conducting additional studies on mice to develop new methods and drug combinations, as there are many combinations of anticholinesterases and anticholinergic agents that could be tried to make delivery of the drugs more predictable through the mucous membranes in the nose or eyes. He is also working to set up future clinical studies with Samuel, Soundara Raj and their colleagues in India. While there is much work in front of them, they have already taken important steps toward addressing a major global need. The entire team has embraced the TCR Multispeciality Hospital motto that “no patient should die from snakebite.”

Matthew R. Lewin, Philip Bickler, Tom Heier, John Feiner, Lance Montauk, Brett Mensh. Reversal of experimental paralysis in a human by intranasal neostigmine aerosol suggests a novel approach to the early treatment of neurotoxic envenomation. Clinical Case Reports, 2013; DOI: 10.1002/ccr3.3

Sunday, July 28, 2013

The sharp-tailed snake vs the developer


Photo credit Bill Bouton.
A friend used to define the difference between a developer and an environmentalist as, one builds houses in forests, and one lives in them. Development can certainly be a threat to some aspects of the environment and cause some species to become expatriated. And, snake populations living in or near developments  can harmed because of the increased encounter rate between humans and snakes.

However, some environmentalists have taken the route of considering virtually everything endangered, this only dilutes the discussion with misinformation and results in a decline in credibility, a problem recently discussed the Onion

And of course, once something is listed as threatened, endangered, or placed on a CITES list it automatically becomes more difficult  for science to study it.

In Pembroke, British Colombia, environmentalists are picking a battle with a developer, they probably can't win. They are attepting to use the sharp-tailed snake, Contia tenius, a threatened species to slow or halt the development of Sunshine Ridge.

The developer describes the community this way:

"The Pemberton Benchlands are set among the evergreens, overlooking the Pemberton Valley. Available home sites will enjoy spectacular views of majestic Mt. Currie, the lush valley farm lands and the surrounding mountain vistas... Pemberton is still the fastest growing community in BC, which makes it both the ideal place to move to and invest."

The environmentals have a different view point. One resident writes,

"This side of Pemberton will be blasted a bit more and will show a start of our planet cancer: high-density housing. How many people is this going to bring over the next 25 years? Twenty-five hundred to 3,000 units on the plans — maybe over 5,000 people, 2,000 dogs (at least) and cats will be chasing wildlife on the MacKenzie Ridge (you can say goodbye to the endangered species like the sharp tail snake). Commercial zoning, hotel resort on the edge of Mosquito Lake, tourism accommodation between the two lakes. This place is more conducive to a tent."

The local newspaper, the Question,  reports that a local environmental organization, the Stewardship Pemberton Society (SPS) was recently successful in securing a grant from the Habitat Conservation Trust Fund in an effort to assist the Village of Pemberton in developing a policy for species-at-risk in large development permit areas.

Apparently this was in direct response to the discovery of the sharp-tailed snake in Pemberton in 2011 within one kilometre of the proposed Sunstone Ridge development. When council approved that Development Permit in February 2012, it was under the condition that snake habitat mitigation plan be implemented.

"Veronica Woodruff of the SPS reported to council during Tuesday’s (July 23) meeting that since beginning an inventory, 10 more of the Sharp-tailed snakes have been found in the Pemberton area. 
“I am not a person that is against development,” said Woodruff. “But I do believe that construction can be done in a partnership and it can benefit both the species and the development.” 
"Woodruff cited examples of snakes coexisting on residential properties in parts of Victoria and the Sunshine Coast islands.
“It's really working proactively with the developers to talk about what we know about the snakes and some ideas on layout, construction mitigation and potential leave areas for these kinds of species.” 
"When Coun. Mike Richman asked what the next step would be in working with the Sunstone Ridge developers, Woodruff replied: 
“We know the preferred types of habitats. It's literally an exercise in Google Earth, looking at the substrate and saying 'OK, it's likely this will be a good nesting and birthing area.' If that's an area that's slated for development, take the time, pull it apart and see what's there or consider leaving that area and tweaking the development. 
"But development is not the only concern for the snakes. Several sightings have occurred on mountain bike trails, with one snake being found dead on Happy Trail after being run over by a mountain bike. Woodruff brought in a large sample of a sign to be mounted near bike trails that read “Brake for Snakes! 
"The SPS will be reporting its final inventory of the Sharp-tailed snakes in September."

In 1960, Sherburne Cook, wrote a short note in Herpetologica (16(3):163-167) on Contia tenius, he wrote "C. tenius is not the rare species previously supposed but perhaps  locally one of the more common species on the West Coast...Furthermore, the range, ecological distribution, and behavior of this snake appear to be closely correlated with a highly utilized food resource - an introduced genus of slug."

In 2010 Feldman and Hoyer (Copeia 2010(2):254-267) described a second species of Contia, C. longicaudae, from northern California and Oregon. There might be some hope here for the Pembroke, BC environmentalists if they can show their local sharp-tailed snake is a distinct - undescribed, cryptic species. But the fact of the matter is  short-tailed snakes are not rare, just secretive. They give the impression of being rare because they are spending much of their time below ground. And, therefore are not good candidates for halting development.