Wednesday, February 22, 2012

New Sea Snake From Australia


Photo credit Brian G. Fry
A paper, published yesterday in the journal Zootaxa, announces the discovery and notes that the new species called Hydrophis donaldii is unique in having raised scales.

“H. donaldii had evaded earlier discovery as it prefers estuarine habitats that are poorly surveyed and not targeted by commercial fisheries”, explained Dr. Bryan Fry, a co-author on the discovery paper and an Associate Professor at the University of Queensland’s School of Biological Sciences.

The scientists collected nine specimens of this ‘viviparous or true’ sea snake from the coastal estuarine habitats of Weipa on the Queensland coast of the Gulf of Carpentaria.

“Weipa really is one of the last sea snake ‘Serengetis’. We can see over 200 sea snakes in a single night’s hunting, whereas sea snake populations have really crashed elsewhere through over-fishing removing their prey and also the snakes drowning in trawling nets.”

“All venomous animals are bio-resources and have provided sources of many life-saving medications, such as treatments for high-blood pressure and diabetes. This reinforces why we need to conserve all of nature as the next billion dollar wonder-drug may come from as unlikely a source as sea snake venom.”

H. donaldii is named in honor of David Donald, Dr. Fry’s long-time boat captain.

“Quite simply we would not have found this snake without Dave’s unique knowledge of the area. I told him we wanted to survey as many distinct types of habitat as possible and he guided us to the perfect spots,” Dr. Fry said.

It is also given the common-name ‘rough-scaled sea snake’ to reflect the unique scalation.

“We don’t know why it has been evolutionarily selected to have such unique scalation, but we will next study its ecology to learn more about it,” the scientist concluded.

Citation
KANISHKA D. B. UKUWELA, KATE L. SANDERS & BRYAN G. FRY. 2012.  Hydrophis donaldi (Elapidae, Hydrophiinae), a highly distinctive new species of sea snake from northern Australia. Zootaxa 3201: 45–57 

Chrysosporium Threatens Endangered Rattlesnake

The Chicago Tribune is carrying the following story: 

CHAMPAIGN, Ill.— A fungus rarely seen in the wild is killing certain southern Illinois rattlesnakes while cropping up in the northeastern U.S., wildlife specialists said.

Matthew Allender, a wildlife veterinarian and University of Illinois visiting instructor of comparative biosciences, said that in 2008 biologists reported to him that they'd found three eastern massasauga rattlesnakes with debilitating fungal infections in a southern Illinois park. The snakes, which are candidates for protection under the federal Endangered Species Act, died within three weeks of their discovery, and a fourth snake with the fungus was discovered in the same park in 2010.

Allender later identified the pathogen as Chrysosporium, a fungus that plagues portions of the pet reptile industry but is not normally seen in the wild. He later heard from other biologists about similar infections in timber rattlesnakes in New Hampshire and Massachusetts.

"Chrysosporium causes disease in bearded dragons and in other snakes, and it's a bad bug," Allender said. "We see it in captive animals worldwide, but we don't typically find it in free-ranging animals."

The fungus also is emerging as a dangerous infection in humans with weakened immune systems, he said, adding that he sees the fungal infection in endangered snakes as a "yellow flag" warranting more study.

"Wildlife diseases and human health are not that different," he said. "And often wildlife are our window into a weakened environment that leads to disease in both people and animals."

Tuesday, February 21, 2012

Fungal Ant Gardens as Incubators for Snake Eggs

Parental care in snakes is poorly documented. It has been known since the 18th century that female pythons will not only guard their eggs but warm them when the ambient temperature drops; female king cobras have been long known to build nests of decomposing vegetation for their eggs and stay nearby; and more recently maternal care in rattlesnakes has been observed. There are other examples scattered in the literature but perhaps most unexpected is the ancient scolecophidians show signs of parental care and since parental care is present in these snakes, the behavior should not be too surprising in the more modern snake lineages. Paleontologist Claude Hibbard discovered a nursery (or a communal egg laying site) of the New Mexico worm snake, Rena dissectus in the 1960’s.
A Liotyphlops albirostris egg on a colony of A. cf. goniodes.
Note that the workers have planted pieces of fungal garden on
the egg’s shell.

Recently Gaspar Bruner and colleagues report the dawn blind snake (family Anomalepididae) Liotyphlops albirostris depositing its eggs in the fungus gardens of the fungus-growing ant Apterostigma cf. goniodes.They found three snake embryos in the nest of the phylogenetically basal attine ant, which has relatively small nests. In an effort to determine if the ants could distinguish snake eggs from a snake-like egg made of a different material, the authors observed the behavioral responses of ants to natural and artificial snake eggs. They transferred the eggs from the nest to a sterile Petri dish and removed the fungal mycelium around the eggs using forceps. Then either a plasticine or natural egg (with the fungus removed), was placed on the top of the fungal garden. Using a stereomicroscope they observed the ants’ behavior toward the egg or the plasticine egg. They found worker ants repeatedly attended and groomed the snake eggs, but never observed the ants biting them. The ant workers took pieces of their fungus garden and planted them on the eggs, behavior very similar to what the workers do with ant eggs, larvae, and pupae in their fungus garden, as a means of controlling infections. When researchers removed the mycelial cover of an egg the ants completely recovered the eggs with fungal garden material and restored it to the original condition but did not attend or cover the artificial egg. Also, the ants spent substantially more time physically examining the snake egg than the artificial egg suggesting the ants were not simply responding to natural eggs as a foreign object. The entire article is available on line.

Citation 



Saturday, February 18, 2012

Another Large Python bivittatus from Everglades NP

The following is from the National Parks Traveler webiste. The story is dated February 17, 2012.

A Burmese python more than 16 feet in length and tipping the scales at 140 pounds has been captured at Everglades National Park, evidence of the problem park officials face with the spread of these non-native constrictors.

The female snake was captured Monday after a park staffer came upon it while spraying non-native vegetation.

Park officials say that "many national parks struggle to manage the impacts on resources by invasive exotic animals and plants, but it seems that the Burmese python in the Everglades has captured the attention of the media and the public on this issue, which may help to focus attention on the larger invasive exotic problem that many land managers are grappling with."

"The park has spent the past few weeks emphasizing to the media and the public the importance of not letting unwanted animals or plants loose," notes Everglades spokeswoman Linda Friar. "It is important to focus on what we have learned from this experience to prevent future invasive exotic infestations and improve our ability to react quickly before a species becomes impossible to eradicate."

While pythons have been a problem in Everglades National Park for much of the past decade, the situation garnered heightened media interest recently due to a study blaming the snakes for a "precipitous declines" in mammals that once were commonly seen in parts of the park.

Though members of the park’s staff are working on containment and science to better understand the impacts of this newest exotic in the park, it appears that eradication is currently not possible on a landscape the size of the park (almost 2400 square miles), Ms. Friar wrote in a release.

Wednesday, February 15, 2012

The Smallest Lizard

Brookesia micra from Nosy Hara, northern Madagascar. (A) adult male on black background, showing orange tail colouration; (B) juvenile on finger tip; (C) juvenile on head of a match; (D) habitat along a small creek on western flank of Nosy Hara, where part of the type series was collected. This is Figure 8 from the original paper.
Size determines much biology in living organisms: what an organism can eat and what eat its, how fast or slow an organims may loose or gain heat and water, and where an organism can or cannot hide. The largest animals tend to be well known, but the smallest may go undetected and overlooked. Until today, the smallest lizard was the gecko Sphaerodactylus ariasae with a snout-vent length of 18 mm and a total length of 33 mm.

Madagascar has about 80 (43%) of the 185 chameleons, and they are all in three genera Brookesia, Calumma, and Furcifer. Brookesia contains about 26 species of ground dwellers that forage in the leaf litter rainforest and dry deciduous forest, climbing to low perches in the vegetation for sleeping. Brookesia are typically dull brown or green, have a short non-prehensile tail that is used as “fifth leg” in walking, and are relative small in size, about 15–65 mm in body length and 25–105 mm in total length. Most species of Brookesia have very small geographic distributions, with almost half of the species known from single localities.

During recent fieldwork in northern Madagascar, Glaw and colleagues discovered several new populations assignable to the Brookesia minima group, some of which are morphologically and genetically distinct from all described species, and they describe four new species in a PLoS One artcile published today.

One of the newly discovered dwarf chameleons is striking cases of miniaturization and microendemism and suggest the possibility of a range size-body size relationship in Malagasy reptiles. The newly described Brookesia micra reaches a maximum snout-vent length in males of 16 mm, and its total length in both sexes is less than 30 mm, ranking it among the smallest amniote vertebrates in the world. With a distribution limited to a very small islet, this species may represent an extreme case of island dwarfism. Brookesia micra was found active on the ground during the day in a mosaic of eroded limestone boulders and dry forest leaf litter, and at night roosting on branches in very low vegetation (about 5–10 cm above the ground). The entire article is available on-line.

Citation
Glaw F, Köhler J, Townsend TM, Vences M (2012) Rivaling the World's Smallest Reptiles: Discovery of Miniaturized and Microendemic New Species of Leaf Chameleons (Brookesia) from Northern Madagascar. PLoS ONE 7(2): e31314. doi:10.1371/journal.pone.0031314

Saturday, February 11, 2012

Hormone Triggers Production of Sex Pheromones in Thamnophis


Garter snake dens in the Interlake region of Manitoba, Canada, are the scene of a mating frenzy  each spring and pfrovide an opportunity for researchers to work out the mechanisms by which snake's choose their mates. The following is based upon an article published in The Journal  of Experimental Biology that experimentally demonstrates that oestrogen triggers to production of the female sex pheromone to attract males to females. Males detect the phromone with theri vomeronasal organ and collect the female's molecules by tongue flicking. Now researchers at Oregon State University have decoded the secrets of chemical signalling in red-sided garter snakes (Thamnophis sirtalils parietalis).  The hormone oestrogen activates sexual signaling  expression in birds and other tetrapods and  M. "Rocky" Parker and Robert Mason thought oestrogen may initiate the production of the sexual signaling  pheromone in garter snake They reasoned that, if oestrogen was the key to their puzzle, exposing male snakes to oestrogen should make males smell like females and therefore irresistible to other males. To test the hypothesis, they collected male redsided garter snakes in Manitoba and surgically inserted oestrogen implants into the males’ body cavities in their Oregon lab. The following spring, they returned the snakes to Manitoba to test whether oestrogen had made them alluring. Placing the altered males in an outdoor arena,they found wild males courted the implanted males. But, seeing that the altered males tried to avoid their love-struck suitors, Parker and Mason devised an additional  test. Starting a mating ball composed of a female surrounded by courting males, they placed an altered male near the mating ball and counted how many males lost interest in the female and directed their attention to the altered male instead. Again, wild males courted implanted males; tricked into believing they were pursuing females. Parker and Mason found the effects were  reversible, the wild males were no longer fooled by altered males once their implants were removed. Oestrogen functions as an ‘on/off switch’ for female pheromone production. When they laid scent trails in a Y-maze – by rubbing male and female snakes along the arms of  a maze, they were astonished to find implanted males were more attractive than small females. ‘Longer females have more babies, so it’s best to court large females’, said Parker. ‘For some reason, oestrogen made males as alluring as large females.’ To find out why, Parker and Mason  collected altered males’ skin lipids and examined their pheromone composition using mass spectrometry. Garter snake sex pheromones are made up of light and heavy methyl ketones, with large females producing mostly heavier ketones. When the researchers plotted the pheromone profiles, they saw that altered males had a heavy pheromone composition, just like large females. ‘It turns out that oestrogen triggers the  reproduction of the heaviest, and therefore sexiest, methyl ketones’, Parker concluded. So, in red-sided garter snakes, oestrogen triggers female pheromone production. This may offer an explanation for the puzzling existence of ‘she-males’ – wild males who naturally produce female sex pheromone but have negligible circulating oestrogen levels. ‘Exposure to oestrogen- mimicking pollutants could explain the presence of she-males’, says Parker; bad news for a species whose reproduction depends solely on chemical cues. ‘But the good news is that the changes are at least reversible’, he adds.

Citation
Parker, M. R. and Mason, R. T. (2012). How to make a sexy snake: estrogen activation of  female sex pheromone in male red-sided garter snakes. Journal of Expiremental Biolology 215: 723-730.

Snake Venom Forensics


In the science fiction classic Bladder Runner, Harrison Ford's character  Rick Deckard tracks down a replicants (synthetic humans) using a scale from an artificial snake. The planet has been turned into a sewer, and most of its life forms other than humans have been obilterated. While we have not quite reached the level of environment degradation depicted in the film, we are consuming snakes at an alarming rate. For a variety of purposes including meat, skins, and venom.

The illegal trade in snake parts in many places in the world has increased in spite laws and legistation to protect snakes. Last August there was a story posted on this blog regarding the illegal trade in snake venom.

A raid on a hotel room in Kerala recovered  the venom and the the local magistrate sent venom samples to the Center for Cellular and Molecular Biology in Hyderabad. The smugglers were charged with illegal hunting and trafficking of a protected animal, both punishable by a prison sentence and fine of 25,000 rupees (about $500). The case is still pending.

 Now Indian scientists (Sing et al. 2012) at the Centre for Cellular and Molecular Biology in Hyderabad have developed a technique of identifying the species of snakes that produced a venom sample.  Their analysis used the primers for cytochrome b frpom the mitochondrial DNA genome and revealed that the venom was extracted from  Indian cobras (Naja naja). On the basis of this report, the  authorites were able to file charges against the accused for illegal hunting of the protected cobra and smuggling of snake venom. This approach potential for rapid identification of snake venom recovered by law enforcement. This paper is also the first report of DNA isolation from dried snake venom for species identification.

Extraction of DNA from snake venom  is difficult because when a snake voluntarily injects or ejects its venom, it usually does not contains snake cells. However, when humans exteact the venom by force tissues of the venom gland are most likely damaged and DNA becomes available from the cells mixed with the venom.

You know its only a matter of time before this becomes a plot on CSI, or one of its spin-offs.

Citation
Singh, C. S., Gaur, A., Sreenivas, A. and Singh, L. (2012), Species Identification from Dried Snake Venom. Journal of Forensic Sciences. doi: 10.1111/j.1556-4029.2011.02049.x

Wednesday, February 8, 2012

Loggerhead Feeding Ecology


Caretta caretta. JCM

GAINESVILLE, Fla. – Satellite tracking of threatened loggerhead sea turtles has revealed two previously unknown feeding ‘hotspots’ in the Gulf of Mexico that are providing important habitat for at least three separate populations of the turtles, according to a study published recently in the journal Biological Conservation.

The two sites, located in the open waters off the coast of Southwest Florida and the northern tip of the Yucatan Peninsula, were found by a team of scientists when they compiled and analyzed loggerhead tracking data.

The researchers' goal was to synthesize tracking data from three genetically distinct loggerhead populations to learn more about how they use the Gulf of Mexico. By identifying the specific location of regularly used habitat, the results provide invaluable information for marine planning and management for this species, whose populations in the Gulf of Mexico are well below historic levels and in recent years have continued to decline drastically in some areas.

The maritime feeding grounds also hold the first clues about how loggerhead sea turtles spend time at sea – which is, in essence, most of their lives.

"Up until now, management actions that affect loggerheads have often focused on their limited time at nesting beaches, or on fisheries regulations," said Kristen Hart, Ph.D., the U.S. Geological Survey research ecologist who led the synthesis. "Our findings open up important new options for marine habitat conservation, and provide valuable geographic data that can be used to strategically locate marine reserves based on the best available science, as called for in the new National Ocean Policy."

"The use of satellite tags for tracking marine animals has opened our eyes to the secret lives of some of nature's most elusive creatures," said USGS director Marcia McNutt, "At first a scientific tool to understand the life cycle of animals, such as white sharks and leatherback turtles, who rarely come into contact with humans, these tags may now be the main hope for understanding what we can do, or what we should stop doing, in order to bring them back from the road to extinction."

Researchers intercepted female loggerheads after their nesting forays to beaches and outfitted them with satellite tags at study sites in the Florida Panhandle, Casey Key in southwest Florida, and Dry Tortugas National Park. They then tracked the females’ migrations and used a new method to determine precisely when they had arrived at "hotspot" foraging areas, in two geographically different locations.

Seven female turtles migrated to foraging sites off Southwest Florida, while the other three took up residence at foraging sites at the Yucatan site. Once the researchers applied the new method for synthesizing their satellite-tracking data, it became clear that these loggerhead turtles from all three populations consistently converged around two common sites. This confirmed a hunch that the researchers had developed after years of tracking turtles.

At both of the feeding hotspots, turtles selected individual sites where they foraged in shallow or nearshore waters less than fifty meters deep. Turtles appeared to prefer their own distinct territories, where they tended to remain resident. This suggests that it may be possible to accurately predict where sea turtles will feed, information that will prove vital for managers looking to focus conservation efforts on prime foraging habitat.

Researchers don't yet know what attracts loggerheads from around the Gulf to these specific feeding areas, although generally, loggerheads forage on the bottom of the sea floor for crustaceans such as crabs, lobsters, clams or conchs.

"The logical next step is to investigate what makes these particular sites 'prime' foraging grounds by mapping and sampling the habitat types found on the sea floor," explained Hart. "It would also be useful to tag loggerheads at these foraging sites to confirm how long they reside in these areas, or alternatively to see where they go next."

Kristen M. Hart, Margaret M. Lamont, Ikuko Fujisaki, Anton D. Tucker, Raymond R. Carthy. Common coastal foraging areas for loggerheads in the Gulf of Mexico: Opportunities for marine conservation. Biological Conservation, 2012; 145 (1): 185 DOI: 10.1016/j.biocon.2011.10.030

Monday, February 6, 2012

A New Semi-Aquatic Lizard from Peru

An adult male Potamites montanicola. G. Chavez & D. Vasques
There are relatively few aquatic or semi-aquatic lizards. The marine iguana feeds underwater and the common iguana uses water to escape predators, as do a few Anolis; some monitor lizards regularly use aquatic habitats; a few teiids also use aquatic habitats for escape (Kentropyx) and the caiman lizards of the genus Dracaena feed in the water. But, some microteiids in the genera Rimia, Neusticurus and Poyamites are also semi-aquatic.

Now, Germán Chávez and Diego Vásquez of the Centro de Ornitología y Biodiversidad (CORBIDI) in Lima, Peru have described an unusual, new semi-aquatic microteiid (family Gymnophtalmidae). The new species, Potamites montanicola, is six to seven cm in body length, with a tail measuring about 10 cm, and has strongly keeled scales over its dorsum.

Members of the genus Potamites (six species) were placed in the genus Neusticurus (five species) until they were separated in 2005 by Doan and Castoe. Two species of Potamites are known from Peru: Potamites ecpleopus and Potamites strangulatus, both of which contain several subspecies. Surveys in 2010 produced a new species of Potamites from southern Peru. The following has been adapted from the original article and an article from Sci-News.com.

“The first specimen of P. montanicola was discovered in Cajadela Native community by Karla García, a member of our team, in August 2010,” said Dr. Chávez in the interview with Sci-News.com. “This only specimen was found when the surveys was ending. One morning, when Karla García was walking back to the camp, this lizard was crossing a trail very close to a creek in a secondary forest.”

The new species is known only from two localities in the Andes of southern Peru,separated by 64 km and located at the Cordillera de Vilcabamba and Apurimac river valley.

“According to our field data, this species is very restricted to streams with fresh temperatures of 14 to 16 Celsius degrees,” Dr. Chávez explained. “The most of the specimens were observed at night, thus we believe that this species is nocturnal (active at night), but we can’t confirm this. We also found some individuals at day (some recently collected specimens). They were always spotted under rocks, probably with lower activity than at night when we found the specimens running or swimming.”

“The males have great colors on the vental region of the body. They can be light blue, electric blue with black spots or yellow with black spots, while the ventral region in females can be creamy white or light red. Males are longer than females. Although we have no records or proofs that P. montanicola is a part of the diet of some snakes, it is probably that this lizard is prey for snakes such as Bothriopsis taeniata, Chironius monticola and even juveniles of Lachesis muta, recorded in the same location.”

The species name is derived from the Spanish ‘montano’, an adjective to describe something from a mountain, and the Latin suffix ‘-icola’ for ‘inhabitant’ and refers to the montane forests where P. montanicola lives.

“This species is the first Potamites recorded in mountain forests at elevation above 2,000 m, that give us an idea about an unknown diversity of Andean Potamites,” Dr. Chávez concluded. “Over the last years, many species of amphibians have been described from Peru, but very few reptiles. Thus, it is another proof of the reptiles richness in our country.”

The article is available on-line.

Chavez G, Vasquez D. 2012. A new species of Andean semiaquatic lizard of the genus Potamites (Sauria, Gymnophtalmidae) from southern Peru. ZooKeys 168:31-43.

Doan TM, Castoe TA. 2005. Phylogenetic taxonomy of the Cercosaurini (Squamata: Gymnophthalmidae), with new genera for species of Neusticurus and Proctoporus. Zoological Journal of the Linnean Society 143: 405-416. doi: 10.1111/j.1096-3642.2005.00145.x

Sunday, February 5, 2012

A 1973 Death from a Sistrurus catenatus Bite Recounted

An article in TheDailyNews.com (New York) recounts the 1973 death of a man from the bite of an eastern massasauga.

HIDDEN HISTORY: Snake bite kills man in Bergen swamp, 1973 By Mark Graczyk

The Bergen Swamp Wildlife Area is a swamp and nature preserve located within the towns of Bergen and Byron.

It's a wonderful spot with a variety of different flora and fauna. Created about 400 million years ago, the swamp was designated a National Natural Landmark in 1964.

Among the many creatures living in the preserve are a small colony of Eastern Massasauga rattlesnakes. These snakes are on the endangered species list. They live in remote areas of the swamp and rarely go near humans.

But on a summer's day in 1973, a rattlesnake bite brought tragedy to this picturesque location.
Gordon D. Ball, 34, of Byron-Bergen Townline Road entered the swamp on Sunday afternoon, Aug. 5. He told relatives he was going on a picture-taking expedition. He brought a camera, a .22 caliber revolver and a few other supplies.

Shortly after 2:30 p.m., Mr. Ball signed a book maintained at the home of Stephen Lane, the swamp caretaker. He began walking on a marked path leading east from the Lane home. It was the last time he was seen alive.

By Sunday night, Mr. Ball had not returned home and relatives contacted police. A massive search of the 30-square-mile swamp began.

By late Monday, a 17-year-old girl visiting from Fresno, Calif., came forward with information. The girl, Nancy Hoe, was staying with her aunt, uncle and cousin at their home on Warboys Road, adjacent to the swamp.

About 1:30 a.m. Monday, Nancy said she heard a man yell for help on two occasions, according to a report in The Daily News. She awakened her cousin and they both listened for a short time, heard nothing further and returned to bed.
Then she heard the cries again about five minutes later.

''Miss Hoe said she was not overly concerned at the cries since she was not aware that anyone was missing in the swamp area,'' The Daily News reported. ''She said she informed her aunt of the yells later Monday when she learned of the disappearance of Mr. Ball.''

The aunt notified police immediately and the search continued for several days with no success. By Friday, few held out much hope that Mr. Ball would be found alive. The search party had grown to include state troopers, conservation officials, area volunteers and a busload of the missing man's fellow workers from his employer in Rochester. Bloodhounds were also used.

Searchers were hampered by the swamp's dense mid-summer vegetation. One police observer called it the most difficult search conditions he had ever seen.

Finally, about 3:10 p.m. Friday, an Air National Guard helicopter spotted the body in a small clearing surrounded by 6- to 7-foot high grass near Warboys Road, on the swamp's northern perimeter.

And not far from the area where the girl from Fresno had heard cries of a man early Monday morning.

Searchers later recounted that they had passed near the spot on at least one other occasion, but couldn't see the body because of the dense vegetation.

Mr. Ball's body was taken to H.E. Turner & Son Mortuary to determine an exact cause of death. Pathologist C.V. Okay later listed the ''presumptive cause'' of death as snake venom poisoning, apparently from a rattlesnake.

The autopsy report said death occurred sometime in the early morning hours of Monday, The Daily News reported. This seemed to corroborate Nancy Hoe's story that she heard a man crying for help about 1:30 a.m. Monday.

Investigators also determined that Mr. Ball had fired his .22 caliber gun four times in hopes that someone would hear him. Several people said they heard gunshots but it wasn't enough to find Mr. Ball in time.

As far as I can tell, this was the only time — at least in recent history — that someone had died of a rattlesnake bite in Genesee County.

Anoles Demonstrate the Founder Effect

Anolis sagrei. Photo credit Neil Losin
The following is a press release from the National Science Foundation.

Biologists who released lizards on tiny uninhabited islands in the Bahamas have uncovered a seldom-observed interaction between evolutionary processes.

Jason Kolbe, a biologist at the University of Rhode Island (URI)--along with colleagues at Duke University, Harvard University and the University of California, Davis--found that the lizards' genetic and morphological (form and structural) traits were determined by both natural selection and a phenomenon called the founder effect.

Their research results are published online today in the journal Science.

The founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It often results in the new population becoming genetically or morphologically different from the original population.

"We rarely observe the founder effect as it happens in nature, but we know that it occurs because islands are colonized by new species over time," said Kolbe.

"What we didn't know was how these evolutionary mechanisms [natural selection and the founder effect] interact with each other."

The scientists learned that differences caused by the founder effect persist even as populations adapt to new environments.

"Evolutionary biologists have been debating the importance of founder effects for more than 70 years," said Sam Scheiner, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research. "This study is the first to definitively demonstrate those effects for ecologically important traits."

Kolbe and colleagues randomly collected brown anole lizards from a large island near Great Abaco in the Bahamas, and released one pair on each of seven nearby islands whose lizard populations had been cleared by a recent hurricane.

The source island is forested, while the other islands have short, scrubby vegetation.

Previous research had found that anole lizards living in forests had longer hind limbs than those found in scrub habitat.

Lizards with longer limbs can run faster on the broad perches available in forests, while short-limbed lizards are more adept at moving on the narrower perches found in lower vegetation.

The scientists revisited each of the islands over the next four years to measure the lizards' limb length and collect tissue samples for genetic analysis.

All the new populations survived and increased an average of 13-fold in the first two years, before leveling off.

"We noticed a founder effect one year after starting the experiment, which resulted in differences among the lizards on the seven islands," Kolbe said.

"Some of the islands had lizards with longer limbs and some had lizards with shorter limbs, but that was random with respect to the vegetation on the new islands."

Because the structure of the vegetation on the islands differed from that of the source island, the scientists predicted that natural selection would lead the lizards to develop shorter limbs.

"Over the next four years, the lizards on all the islands experienced a decrease in leg length that is attributable to natural selection," Kolbe explained. "But those that started out with the longest hind limbs still had the longest hind limbs."

The fact that the populations maintained their order from longest to shortest limbs throughout the experiment means that both the founder effect and natural selection contributed to their current differences.

According to Kolbe, the founder effect is rarely observed in nature, with most previous research conducted in the laboratory.

"Ours is the first to study this process experimentally in a natural setting, and we were able to account for multiple evolutionary mechanisms through time," he said. "We manipulated the founding of these islands, but everything else about it was natural."

The next step in the research will be to determine how long the founder effect persists before other factors erase its signature.

Co-authors of the paper are Kolbe; Manuel Leal of Duke University; Thomas Schoener and David Spiller of the University of California, Davis; and Jonathan Losos of Harvard.

The study was also funded by the National Geographic Society.

Citation
Kolbe JJ,  Leal M,  Schoener TW,  Spiller DA, Losos JB. 2012. Founder Effects Persist Despite Adaptive Differentiation: A Field Experiment with Lizards. Science 1209566 Published online 2 February 2012 [DOI:10.1126/science.1209566]

Saturday, February 4, 2012

Salamanders & Road Salt

Ambystoma maculatum. JCM
New Haven, Conn.—Spotted salamanders exposed to contaminated roadside ponds are adapting to their toxic environments, according to a Yale paper in Scientific Reports. This study provides the first documented evidence that a vertebrate has adapted to the negative effects of roads apparently by evolving rapidly.

Salamanders breeding in roadside ponds are exposed to a host of contaminants from road runoff. Chief among these is sodium chloride from road salt, which reaches average concentrations of 70 times higher in roadside ponds compared to woodland ponds located several hundred feet from the road.

“While the evolutionary consequences of roads are largely unknown, we know they are strong agents of natural selection and set the stage for fast evolution,” said Steven Brady, the study’s author and a doctoral student at the Yale School of Forestry & Environmental Studies. “These animals are growing up in harsh environments where they face a cocktail of contaminants, and it appears that they are evolving to cope with them.”

Brady found that salamanders in roadside ponds have higher mortality, grow at a slower rate and are more than likely to develop L-shaped spines and other disfigurements. In roadside ponds, only 56 percent of salamander eggs survive the first 10 weeks of development, whereas 87 percent survive in the woodland ponds. As roadside ponds become more toxic, the surviving salamanders may develop a genetic advantage over their counterparts living in woodland ponds.

The salamanders that survive year after year in the roadside ponds appear to have adapted to the harsh conditions. “The animals that come from roadside ponds actually do better—substantially better—than the ones that originate from woodland ponds when they’re raised together,” Brady said.

That animals adapt to human activities is not altogether new. For example, fish have begun to mature at smaller sizes in response to commercial fishing. But whereas humans directly utilize fish for consumption, salamanders are just bystanders to human activities. This suggests that the majority of species, which are not specifically targeted for human use, may be experiencing profound evolutionary consequences. And it appears that even species not being driven to extinction—and seldom thought about—are changing.

“This adaptation is certainly encouraging for conservation,” said Brady. “But our modern footprint is fundamentally changing species in ways we don’t understand and, critically, we don’t know if these adaptive responses will keep pace with environmental change.”

Brady observed the development of the salamanders in 10 ponds—five roadside and five woodland—at Yale Myers Forest and in the town of Willington, both in northeastern Connecticut. The paper, “Road to Evolution? Local Adaptation to Road Adjacency in an Amphibian (Ambystoma maculatum),” is available at www.nature.com.

Citation
Steven P. Brady. 2012. Road to evolution? Local adaptation to road adjacency in an amphibian (Ambystoma maculatum). Scientific Reports, 2012; 2 DOI:

Two New Blindsnakes From Oceania

The widespread Ramphotyphlops braminus. JCM
Blind snakes of the family Typhlopidae number about 250 species and are found throughout the tropical and sub-tropical world in Asia, Africa, Australia, and South America. The family is also well represented in the island archipelagos of Greater and Lesser Antilles, the Philippines, and the Solomon Islands, but its members are mostly unknown in Oceania north of Melanesia and east of Palau. The exception is the flower pot snake, Ramphotyphlops braminus, a parthenogenetic species that has been carried around the world by humans. More than 30 blind snake species have island distributions in the western Pacific, from the Philippines in the north to Fiji in the south. But, only two species are reported from Oceania to the north and east of this arc: Typhlops pseudosaurus from Guam (now regarded as Ramphotyphlops braminus and Ramphotyphlops acuticaudus from Palaua. Ramphotyphlops acuticaudus is similar to Ramphotyphlops flaviventer and related species from Halmahera eastward through New Guinea and the Solomon Islands to Fiji is the only recognized species that occurs inside this island arc, and other than R. braminus, no blind snakes occur eastward in Micronesia. Two recent discoveries suggest blind snakes occur within the Caroline Islands and are possibhly widespread. In 1999, a typhlopid was collected on Pasa Island, Ant Atoll from inside a rotted Cocos trunk that was lying on the ground. Subsequently, the presence of blind snakes on Ulithi, approximately 2000 km to the west of Ant Atoll. Comparison of these specimens from Ant Atoll and Ulithi, along with more recently collected specimens, indicate that they represent two similar undescribed species of Ramphotyphlops. These two snakes have now been described byn Addison Wynn and colleagues (2012).

Ramphotyphlops adocetus is from Ant Atoll, Pasa Island Caroline Islands, and Ramphotyhlops hatmaliyeb is from Giilab Island, Ulithi, Caroline Islands

The authors point out such low-lying atolls as Ant and Ulithi are usually inhabited by widespread, highly adaptable species. Except for Ramphotyphlops adocetus, the terrestrial vertebrate fauna of Ant Atoll is a subset of more broadly distributed species also occurring on Pohnpei, and the reptiles found on Ant Atoll are all species inhabiting many of the Caroline Islands and beyond. The only other reptiles known solely from atolls in the Caroline Islands east of Palau are the geckos Perochirus scutellatus, endemic to (Kapingamarangi Atoll); and P. cf. scutellatus (endemic to Ulithi on Sorenleng Island; Bulbul, Giilab, Iaar, Soong, and Yeew islands) and Lepidodactylus oligoporus, known from only from a single island on Namoluk Atoll.

Pacific atolls, are recent phenomena and form form unconsolidated sand and gravel piled on top an emergent paleoreef, making them only 1000 to 2000 years old, but were built upon the rims of karst platforms exposed when sea levels were as much as 125 m lower during the peak of the last glaciation. Today’s atolls formed after present sea levels were reached after sea level was lowered 1.0 to 2.6 m about two thousand years ago. If the two new blind snakes require stable, perched atolls for habitat, they must have dispersed to Ant Atoll and Ulithi no more than two thousand years ago, possibly from the relatively close high islands of Pohnpei and Yap. But, the snakes remain unknown from those islands at the present time.

Citation
Wynn, A. H, Reynolds, RP, Buden, DW, Falanruw, M., & Lynch, B. 2012. The unexpected discovery of blind snakes (Serpentes: Typhlopidae) in Micronesia: two new species of Ramphotyphlops from the Caroline Islands. Zootaxa 3172:39-54.

Thursday, February 2, 2012

Dog Survives Coral Snakebite

It is good to know that coral snake antivenom, while apparently not available for humans in the USA, is available for dogs! The following story is from the Health New Digest.com. 

Gainesville resident Larry Ferguson relaxes at home with his dogs, Max, left, and Whiskey, who survived a coral snake bite after being treated at the UF Small Animal Hospital. (Photo courtesy of Larry Ferguson.) 
“Red on yellow, kill a fellow; red on black won’t hurt Jack” might be a familiar folk rhyme in Florida and elsewhere in the deep South to distinguish the deadly Eastern coral snake from the harmless scarlet king snake. But Larry Ferguson, who recently moved to Gainesville from Arkansas, had never heard of a coral snake, much less the danger they pose. 
Alerted by his two dogs barking, Ferguson went outside to find a colorful banded snake dead near a clearly distressed dog in the yard. A call to his veterinarian, Dr. Janine Tash of Aalatash Animal Hospital in Gainesville, revealed that the dog, a 3-year-old pit bull terrier named Whiskey, had most likely been bitten by a coral snake 
Ferguson was told that the University of Florida Small Animal Hospital was the only place his animal could receive the antivenom that could possibly save his life. He rushed Whiskey to the hospital’s emergency room. 
“In the yard, he’d been panting heavily,” Ferguson said. “On the drive to the ER, I could see him shaking. I knew he’d been bitten.” 
Upon Whiskey’s arrival at UF, however, emergency veterinarians noted that the dog was bright, alert and responsive with no visible signs of a snakebite, although they said this is not unusual because coral snakes have very small teeth. Whiskey received antivenom, but unfortunately developed paralysis despite the treatment. 
“Within only a few hours, Whiskey began showing clinical signs, becoming totally paralyzed and unable to breathe,” said Dr. Luiz Bolfer, a resident with the UF Small Animal Hospital’s emergency and critical care service. 
The dog, unable to breathe by himself, was placed on a mechanical ventilator for four days. The snake’s venom also led to acute kidney disease. Several different medications were administered to perfuse the animal’s kidneys, increase his urine output, decrease the acid in his stomach, regulate acidic content in his blood and control his irregular heartbeat, Bolfer said. 
“Whiskey had no muscle ability,” said Ferguson, who manages a textbook store in Gainesville. “His diaphragm wouldn’t work. His lungs were fine, but his muscles wouldn’t allow him to use them.” 
So Ferguson waited and hoped. 
“My first inclination was to pay for the antivenom and if that didn’t work …” he said, his voice trailing. “I’d always heard of people spending a lot of money on pets. Initially, you might say you won’t do that, but you never know what you’ll do when you’re in the situation. I wound up doing a lot more than I thought I would.” 
After four days at the UF Small Animal Hospital, Whiskey started to breathe on his own. Veterinarians took him off of the ventilator. The dog remained paralyzed, but was breathing normally. He began to improve a little every day, although veterinarians continued to treat him for the other problems and for pneumonia, a common complication associated with ventilator treatment 
“Finally, he started moving his legs and we moved him to a bed on the floor,” said Bolfer. “Whiskey was still not able to swallow due to his muscle paralysis, so we placed a feeding tube that bypasses the mouth to deliver food directly to his stomach.” 
On the eighth day, Whiskey began eating canned food on his own. The feeding tube was removed and 10 days after arrival, Whiskey was finally discharged and able to return home with his owner. 
“He’ fine,” Ferguson said. “He’s just tired a lot, but he’s been walking a lot. He’s just a sweet dog to begin with.” 
During the course of treatment, UF veterinarians finally found the snake’s tiny bite marks … on Whiskey’s tongue.

Wednesday, February 1, 2012

New 30-foot Fossil Croc from Africa

Aegisuchus witmeri. A 30-foot, flat-headed crocodile. Original art work by Henry Tsai, University of Missouri
A University of Missouri researcher has identified a new species of prehistoric crocodile. The extinct creature, nicknamed "Shieldcroc" due to a thick-skinned shield on its head, is an ancestor of today's crocodiles. Its discovery provides scientists with additional information about the evolution of crocodiles and how scientists can gain insight into ways to protect the species' environment and help prevent extinction.


The discovery was published this week in the journal PLoS ONE (Public Library of Science). "Aegisuchus witmeri or 'Shieldcroc' is the earliest ancestor of our modern crocodiles to be found in Africa," said Casey Holliday, co-researcher and assistant professor of anatomy in the MU School of Medicine. "Along with other discoveries, we are finding that crocodile ancestors are far more diverse than scientists previously realized."

Shieldcroc is the newest discovery of crocodile species dating to the Late Cretaceous period, approximately 95 million years ago. This period is part of the Mesozoic Era, which has been referred to as the "Age of the Dinosaurs;" however, numerous recent discoveries have led to some scientists calling the era the "Age of the Crocs," Holliday said.

Holliday identified Shieldcroc by studying a fossilized partial skull specimen, which was discovered in Morocco and held by the Royal Ontario Museum of Toronto for several years before Holliday analyzed it. By analyzing blood vessel scarring on the bone, Holliday determined that the crocodile would have had a structure on top of its head, resembling a shield. The dents and bumps on the bone indicate veins delivered blood to a circular mound of skin, something never before seen in a crocodile. He said the shield was likely used as a display structure to attract mates and intimidate enemies and possibly as a thermo-regulator to control the temperature of the animal's head.

Holliday compared Shieldcroc's skull to those of other crocodilians. By comparing slopes of various bones, he found that the new species had a flatter skull than other known species. With this information, he believes it is unlikely that Shieldcroc wrestled dinosaurs on or near the shoreline. Instead, Holliday said the fossil indicates that Shieldcroc had thin jaws, likely used to catch fish.

"We believe Shieldcroc may have used its long face as a fish trap," said co-author Nick Gardner, an undergraduate researcher at Marshall University, who collaborated with Holliday on the study. "It is possible that it lay in wait until an unsuspecting fish swam in front of it. Then, if it was close enough, Shieldcroc simply opened its mouth and ate the fish without a struggle, eliminating the need for strong jaws."

In addition, Holliday analyzed Shieldcroc's skull and brain to estimate the overall size of the reptile. He said scientists often use head size of an animal to estimate its total length. Using several parameters, Holliday and Gardner estimate that this specimen had a 5-foot long head and was 30 feet long.

"Scientists often estimate body size of crocodilians based on the size of the skull," Gardner said. "However, estimating the body size of Shieldcroc was difficult, due to the enormous size of the skull compared to other crocodilians. To make a size estimate, we compared several features of the bone to many different species."

Although Shieldcroc lived more than 90 million years ago, Holliday said scientists can use information about the animal to gain a better understanding of today's crocodiles. He said this insight grows in importance as humans encroach on ecosystems.

"Today's crocodiles live in deltas and estuaries, the environments put under the most stress from human activity," Holliday said. "By understanding how these animals' ancestors became extinct, we can gain insight into how to protect and preserve the ecosystems vital to modern crocodiles."

The Shieldcroc fossil studied by Holliday and Gardner is being returned to the Royal Ontario Museum, where it will be put on display later this year.

Citation
Holliday, CM & Gardner NM. A New Eusuchian Crocodyliform with Novel Cranial Integument and Its Significance for the Origin and Evolution of Crocodylia. PLoS ONE, 2012; 7 (1): e30471 DOI: 10.1371/journal.pone.0030471