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.



Thursday, July 25, 2013

Two western garter snakes proposed as threatened

Thamnophis rufipunctatus
The U.S. Fish and Wildlife Service propose to  list the northern Mexican gartersnake (Thamnophis eques megalops) and narrow-headed gartersnake (Thamnophis rufipunctatus) as  threatened taxa on July 10, 2013. Comments are accepted on this proposal until September 9, 2013.

The northern Mexican gartersnake had a limited historical distribution in New Mexico that consisted of scattered locations throughout the Upper Gila River watershed in Grant and western Hidalgo Counties, including the Upper Gila River, Mule Creek in the San Francisco River sub-basin, and the Mimbres River. The species was detected at only 2 of 11 historical localities along the northern-most part of its range from which the subspecies was previously known. The only viable northern Mexican gartersnake populations in the United States where the subspecies remains reliably detected are all located in Arizona.  In New Mexico, the northern Mexican gartersnake may occur in extremely low population densities within its historical distribution; limited survey effort is inconclusive to determine extirpation. The status of the northern Mexican gartersnake on tribal lands, such as those owned by the White Mountain or San Carlos Apache Tribes, is poorly known due to historically limited survey access and less is known  about the current distribution of the northern Mexican gartersnake in Mexico due to limited access to information on survey efforts and field data from Mexico.

After no confirmed sightings in nearly twenty years, scientists discovered three northern Mexican gartersnakes along a stretch of the Gila River in southwestern New Mexico in June. After nearly three years of intensive searching, scientists with the BioPark Zoo in Albuquerque discovered three young males along the Gila, suggesting  at least one viable reproducing population of the northern Mexican gartersnake exists in the region. Northern Mexican gartersnakes inhabit riparian wetland and prey on tadpoles and small fishes. More than 90% of their habitat has disappeared due to overgrazing, water diversions, wildfires and drought.
A proposed diversion of the Gila would alter the river’s modest flood pattern and transport  water to an off-channel reservoir via a pipeline. This would  damage some of the last  remaining habitat in the Gila drainage.

The historical distribution of the narrow-headed gartersnake ranged across the Mogollon Rim and along its associated perennial drainages from central and eastern Arizona, southeast to southwestern New Mexico at elevations ranging from 2,300 to 8,000 ft (700 to 2,430 m). The species was historically distributed in headwater streams of the Gila River sub-basin that drain the Mogollon Rim and White Mountains in Arizona, and the Gila Wilderness in New Mexico; major sub-basins in its historical distribution included the Salt and Verde River sub-basins in Arizona, and the San Francisco and Gila River sub-basins in New Mexico Researchers suspect the species was likely not historically present in the lowest reaches of the Salt, Verde, and Gila rivers, even where perennial flow persists. Numerous records for the narrow-headed gartersnake (through 1996) in Arizona are maintained in the GFD’s Heritage Database. The narrow-headed gartersnake as currently recognized does not occur in Mexico. Recently narrow-headed gartersnakes were detected in only 5 of 16 historical localities in Arizona and New Mexico surveyed in 2004 and 2005. Population densities have noticeably declined in many populations, as compared to previous survey efforts.

The narrow-headed gartersnake  populations have likely deteriorated as a result of declines in resident fish communities due to heavy ash from wild fires and sediment flows, but subsequent survey data have not been collected. If the Whitewater Creek and Middle Fork Gila River populations did decline as a result of these factors, only three remaining populations of this species remain viable today across their entire distribution. Unnaturally large wildfires have become increasingly common across the Mogollon Rim of Arizona and New Mexico where the narrow-headed gartersnake historically occurred.

Friday, July 19, 2013

Suizo Report -- Ellie Drops

Howdy Herpers,                                             07/20/13

First off, Typing Boy sometimes sends out "knock your socks off" missives that he expects multiple "ooos and ahhhs" from the gallery. And all he gets in return is the sound of crickets. There is no accounting for taste with this audience. Then, whilst mired in email Armageddon, he sends out a missive that requests responses from three people, and about 50 of you respond!

What with being a very active president of a herp society, organizing 2 new websites, and herping until he drops, I hope that those of you 50 who said "got it" will forgive me if I didn't respond with "got yours too!"

And if you don't know what I'm talking about, you're likely blessed to be on the second list that was spared that type of lunacy.

Count your blessings!

I'm going to do something that I've never done before. I'm not comfortable doing this. We all get emailed monetary leg humps from this org or that org--and at least they are smart enough, (desperate enough?), to become non profits. While we of the Suizo Project SHOULD do that--the 800-1200 bucks that it takes to do that always winds up being spent on transmitters, PIT tags, receivers etc. In other words--useful stuff!

Ok, enough with the BS. I'm asking for money. A new batch of transmitters have just arrived. The little old winemaker coughed up the 700 bucks to pay for that. This with the blessing of his lovely wife Dianna. This was just a stop gap order. Every one of those transmitters has already been requested by our subjects. (They don't know that they requested it, but they did.) Once those surgeries are done, there will be more animals that need the old transmitters that we yank. That will be another $700. And with three steady trackers, we have never have we been more ready to add in new animals.

Those are 400 bucks each. We've already released 2 VERY good candidates for the study due to fiscal woes.

So no, you can't take it off your taxes. We will of course entertain giving animals a name you choose for a hefty donation--but does that really matter? If you donate, you know that the study will continue, and you will also know that you can count on good reports so that you can herp vicariously with us. And join us on the ground as well.

To show what unmitigated gall we have, we're asking you to do this the hard way. Cut a check, make it out to me, stick it in an envelope, and send it to me at:

Roger Repp
C/O NOAO
950 N. Cherry Ave
Tucson, AZ 85719
Phone: 520-318-8210

Every penny donated goes for equipment. We don't get a salary, and we pay gas and beer money out of pocket. (Although you have the right to designate the money be spent on beer. Who are we to turn down free binges?)

If you want to avoid all this hassle, and want to give, we can arrange to have you pay the makers of transmitters with a credit card.

Thanks for your consideration. If it doesn't bring in any money, we'll continue to the best we can with what we have. Thanks.

Good old female tiger rattlesnake # 12, "Ellie." Her transmitter was due to expire 7 June of this year. They normally expire early. By mid-May, the edict "get Ellie" was burned in our brains. Only you can't easily get something that remains invisible in rocky rubble-- unless you want to strip mine certain pristine patches of ground. That we will not do--we will lose an animal first. (Not necessarily because of strict environmental codes of ethics, but more likely because of our lack of desire to swing pick axes and shovels).

In all of 2013, we did not ONCE see Ellie up. With the few glimpses that we had of her, she was buried deeper than a Texas tick. Even those visuals were rare--only one for me. And so 7 June came and went, and we started to intensify the hunt for her. I have 20 write ups of the same rock shelf that is packed with Neotoma debris to show for these writeups. The saving grace was that she was in with a tortoise--so at least I got to watch that during the process.

FINALLY, on 6 July, we got our first rain storm. Every snake we tracked was up--including the erstwhile Ellie. It was nothing short of a miracle that her transmitter was still working. We snagged her, and noted that she was WAY too pregnant to endure a surgery and release. So, Marty hung on to her. She dropped five kids and one stillborn baby on 10 July. All the images that follow come to us by way of Marty Feldner.

I thought I'd start with the first courtship event that we witnessed last year, and bring us on to the present. The images are labeled clear enough for you to see the action. Note how skinny CT12 is after her ordeal. Can you spare 90 cents, so we buy her a mouse? :-)
We are currently watching two more pregnant tigers where transmitter changes will NOT be a problem. We also have one black-tailed rattlesnake about to drop. We hope to share these exciting moments with you insitu.




For now, whether you donate or not, please enjoy these breathtaking images. And know that more will be on your screen soon.

Best to all of you, roger



A lost frog from the lost world


Allobates amissibilis sp. nov., 
newly discovered micro-endemic frog. 
© M. Hölting & R. Ernst/Senckenberg.
Dresden, 17. July 2013. Ecotourism and Conservation - Can it  work? In the context of a study in the forests of central Guyana, a team of scientists from the Senckenberg Research Institute in Dresden investigated this very question and by chance found a previously undiscovered species of frog that only exists in a very limited area of the Iwokrama Forest.

The related study was published in the scientific journal “Organisms, Diversity and Evolution”. The Lost World, a famous novel released by the renowned British author Sir Arthur Conan Doyle in 1912, is set in to what, even today, is still a virtually forgotten and neglected area of our planet, the Guiana Shield in the north of South America. The region accounts for more than 25 percent of the world’s  tropical rain forests, and is one of the four remaining extensive pristine forested areas left in the world (Amazon, Congo, Papua New Guinea and Guiana Shield). In a study sponsored by the Stiftung Artenschutz [Species Conservation Foundation] and the Verband Deutscher Zoodirektoren [Association of German Zoo Directors], the Dresden team, led by biologists Dr. Raffael Ernst and Monique Hölting investigated whether conservation of amphibians and ecotourism can be reconciled in the forests of Guyana. The investigations are being carried out in close co-operation with the international notfor-profit organization Iwokrama international Centre for Rain Forest Conservation and Development. Their idea is to test the concept of a truly sustainable forest, where conservation, biodiversity safeguarding, environmental balance and economic use can be mutually reinforcing. Beside forms of sustainable forest management, ecotourism concepts are also being tested. This is also true of the project area, Turu Falls, at the foot of the Iwokrama Mountains in the so-called Iwokrama Forest of Central Guyana.

The original aim of the study was to investigate the populations of Hoogmoeds harlequin frog (Atelopus hoogmoedi), in order to find out whether these morphologically very variable frogs may be affected by the planned tourism activities. The results will lead in the medium term to a sustainable development plan for the area, with Atelopus receiving the role here of a so-called flagship species, i.e. a species which stands as representative for the protection of the entire area. A frog that is virtually already lost. During the fieldwork for this project, the researchers were struck by an inconspicuous brown frog, only the size of a thumbnail, which they could not assign to any known species. As it turned out, it was indeed a hitherto undescribed species of poison dart frog which is now being scientifically described jointly by Dresden and Belgian scientists.

As inconspicuous as the frogs appear, they are unique. To date, only three species of the genus Allobates are known from Guyana, one of which, the Cuckoo frog, Allobates spumaponens Kok & Ernst 2007, was described for the first time by the same team in 2007.  Moreover, the newly discovered little frog is the third known microendemic species, i.e. which only occurs in the very small area of the Iwokrama Mountains.

So far, only a gecko and a caecilian, a legless amphibian, are known from this area as having a similarly limited distribution. Because of their limited distribution and usually small total population sizes, micro-endemic species are particularly vulnerable to changes in their environment. It is therefore questionable whether the use of the area as a destination for ecotourism will not ultimately lead to the loss of a species, which has only just been discovered and thus has been made accessible to scientific investigation. In order to draw attention to this fact, researchers have given the little amphibian the distinctive name Allobates amissibilis (in Latin “that may be lost”).

We must nevertheless still hope that not least due to the research work of the Dresden team, all is not lost for the forgotten world in the north of South America.The Guiana Shield: Worthy of protection. Not least because of the high number of endemic species, the region is one of the most important centers of biodiversity in the tropics of the New World. Even though the forests of the Guiana Shield have had among the lowest deforestation rates of the world, with very little change over the past decades, rapid economic and social changes are posing increasing pressures on these relatively well conserved forest ecosystems. The Guianas are at a crossroads concerning decisions and trade-offs among utilization, conservation and preservation of their forests and thus substantial parts of the region’s biodiversity

Citation
Kok PJR, Hölting M, Ernst R. 2013. A third microendemic to the Iwokrama Mountains of central Guyana: a new “cryptic” species of Allobates Zimmerman and Zimmerman, 1988 (Anura: Aromobatidae). Organisms Diversity & Evolution, 2013; DOI: 10.1007/s13127-013-0144-4

Wednesday, July 17, 2013

Fruit-eating in crocodilians

Reptile roles in ecosystems are frequently acknowledged as predators, scavengers and prey but their role as pollinators and seed dispersal agents are often overlooked.  In a forthcoming paper in the Journal of Zoology Platt et al (2013) report on the evidence that crocodilians disperse seeds.

The authors ask the questions: (1) Do crocodilians consume fruit and if so, how widespread is this behavior among the order Crocodylia? (2) If fruits are present in the diet, are these ingested incidental to prey capture, consumed as gastroliths, derived secondarily from ingested prey or deliberately ingested as food? (3) Does fruit consumption yield a nutritional reward for crocodilians? (4) What is the fate of fruits and seeds ingested by crocodilians? (5) Are movement patterns of crocodiles likely to extend the seed shadow much beyond the parent plant? (6) What are the ecological implications of this plant–animal interaction; that is, do crocodilians function as seed dispersers?

The authors find  frugivory is widespread among the Crocodylia and while some frugivory is certainly accidental, but the literature leaves little doubt that on occasion, crocodilians deliberately eat fruit. Crocodilians are probably best considered occasional frugivores that is, generalist predators that complement an otherwise carnivorous diet with fruit, which is consumed infrequently and usually, but not always in small quantities.

Although fruit seems of limited importance in crocodilian diets, nutritional benefits are likely. The diversity of fruit types consumed by crocodilians seems to preclude the existence of a specific crocodilian dispersal syndrome similar to that described for other reptiles (aromatic, colorful fruits, borne at ground level or dropped at maturity) . Nonetheless, several lines of evidence strongly suggest that crocodilians potentially function as effective agents of seed dispersal. They  are capable of ingesting large numbers of fruits and seeds, and because these are swallowed without mastication, seeds are likely to escape damage during ingestion. Also, the large gape capacity of crocodilians permits the ingestion of large    fruits. Once ingested, the fate of seeds is less clear; while digestive predation of some seeds undoubtedly occurs, most are probably regurgitated or excreted in the feces. Because crocodilians have large territories and frequently undertake lengthy movements, they are capable of generating extensive seed shadows; seeds are transported well beyond the parent plant before being voided. Although little is known about the ultimate deposition of seeds ingested by crocodilians, the few available reports suggest that defecation sites could prove suitable for seed germination. The authors conclude that it likely that crocodilians function as significant seed dispersal agents in many freshwater ecosystems.

Citation
Platt, S. G., Elsey, R. M., Liu, H., Rainwater, T. R., Nifong, J. C., Rosenblatt, A. E., Heithaus, M. R. and Mazzotti, F. J. (2013), Frugivory and seed dispersal by crocodilians: an overlooked form of saurochory?. Journal of Zoology. doi: 10.1111/jzo.12052

Saturday, July 13, 2013

Snake pattern evolution


Color patterns of snakes have been the subject of many studies and even more speculation. Why is it that some species are uniform in color, while others are striped, banded, or some other combination of patterns. Allen and colleagues (2013) note that an understanding of the diversity of color patterns found in snakes requires detailed pattern measurements. But, that the most common approach to snake pattern quantification is often subjective classifications based on researchers’ observations of whether, for example, a snake is blotched, uniform, longitudinal or transverse striped or an apparent mimic or nonmimic. Categorical classification may be appropriate for answering specific questions, but it masks considerable variation within categories and reduces the ability to detect evolutionary patterns.

Alan et al  built a molecular phylogeny using up to 4 genes for each taxon: 2 mitochondrial (cytochrome b and ND4) and 2 nuclear (c-mos and RAG1). They used 171 taxa from Australia and North America. They then collected colored photographs of each species of snake, excluding captive bread specimens - using 828 photos in all.  The third step was to gather ecological information on each species using the literature. They then used an R-D model, and recruited observers to classify the patterns. They then used a phylogenetic generalized least squares (PGLS) analyses in the caper package  for R (R Development Core Team) to determine how snake patterns are related to  ecology and behavior.

They found a uniform  pattern was associated with an active hunting strategy. Species with longitudinal stripes were generally small, fast, and often exposed to visually hunting predators. Species frequently classified as having regular spotted patterns were more common in North America, found frequently near cover, and predators of birds. Transverse stripes were seldom on species with grasslands or arboreal lifestyle. When they removed coral snake mimics from the sample, transverse stripes are predicted by erratic movement, habitat specialism, and egg consumption. Blotched patterns  associated with an ambush hunting strategy, slow movement, large body size, and pungent cloacal defense. The model of complex patterning showed a positive association toward species where females grow longer than males, those which live in North America and those which are more terrestrial.

High contrast between the colors and tones of pattern elements was observed on small terrestrial snakes and those that can move rapidly away from threats. Habitat generalists generally had patterns with smaller elements in absolute terms, but none of the predictors were associated with the size of pattern elements relative to snout-vent length.

When mimics were included in the analysis, no predictors were related to the cryptic color score. However, when mimics were removed, the minimal adequate color model included main effects of escape speed, mammalian predation, and cloacal defense, with snakes that are slow, predate on mammals, and described as having highly pungent cloacal defenses generally having more cryptic colors.

Transverse striped snakes did not show a clear overall pattern to  eco-behavioral associations; the idea that transverse stripes achieve flicker-fusion during escape is plausible but requires focused empirical testing. Though analysis of snake color was coarse, the expectation that bright colors would be common on well-defended species to function as an aposematic signal was not supported; the factors that lead to the evolution of warning coloration in snakes await further investigation.

Citation
Allen WL, Baddeley R, Scott-Samuel NE, Cuthill IC. 2013, The evolution and function of pattern diversity in snakes. Behavioral Ecology 10.1093/beheco/art058