Thursday, May 25, 2017

Cuban boas coordinate their hunting behavior

Snakes have long been thought to be solitary hunters. A new study from the University of Tennessee, Knoxville, shows that the Cuban boa (Chilabothrus angulifer) coordinate their hunts to increase their chances of success. Vladimir Dinets, a research assistant professor of psychology at the University of Tennessee, observed Cuban Boa's hunting behavior in bat caves. Many Cuban caves shelter large bat colonies, and in some of them small populations of boas regularly hunt bats as they fly out at dusk and return at dawn. Dinets noticed that the boas hung down from the ceiling of the cave entrance and grabbed passing bats in midair. He found that if more than one boa was present, the snakes coordinated their positions in such a way that they formed a wall across the entrance. This made it difficult or impossible for the bats to pass without getting within striking distance of at least one boa. Such group hunts were always successful, and the more snakes present the less time it took each to capture a bat. But if there was only one boa, it sometimes failed to secure a meal. These findings were recently published open-access in the journal Animal Behavior and Cognition. To date, only a handful of snakes have been observed hunting in groups, and coordination among them -- or among any other group-hunting reptiles -- has never been proven, Dinets said. Only a few of the world's 3,650 snake species have ever been observed hunting in the wild, so very little is known about snakes' diverse hunting tactics. "It is possible that coordinated hunting is not uncommon among snakes, but it will take a lot of very patient field research to find out," Dinets said. He added that observing the Cuban boa, although an amazing spectacle, is becoming increasingly difficult since only the most remote caves still have boas. The boas are being hunted for food and possibly pet trade. "I suspect that if their numbers in a cave fall, they can't hunt in groups anymore and might die out even if some of them don't get caught by hunters," Dinets said. "A few of these caves are in national parks, but there's a lot of poaching everywhere."




Citation

 Dinets V. 2017. Coordinated hunting by Cuban boas. Animal Behavior and Cognition, May 2017 DOI: 10.12966/abc.02.02.2017

Coral snake mimic loses pattern in absences of coral snake model

Tobago's Erythrolamprus ocellatus above. Trinidad's coral snake 
mimic E.  
aesculapii below.
Losses of adaptations in response to changed selective pressures are evolutionarily important phenomena but relatively few empirical examples have been investigated in detail. To help fill this gap, Hodson and Lehtinen took advantage of a natural experiment in which coral snake mimics occur on two nearby tropical islands, one that has coral snake models (Trinidad) and one that lacks them (Tobago).

The Tobago snake's pattern represents a loss of an adaptation in response to changed selective pressures. Relatively few empirical examples of adaptation loss have been investigated in detail. Hodson and Lehtinen took advantage of a natural experiment in which coral snake mimics occur on two nearby tropical islands, one that has coral snake models (Trinidad) and one that lacks them (Tobago). On Tobago, an endemic coral snake mimic (Erythrolamprus ocellatus) exists but has a relatively poor resemblance to coral snakes. Quantitative image analysis of museum specimens confirmed that E. ocellatus is a poor mimic of coral snakes.

To address questions related to the functional importance of this phenotype, the authors conducted a field experiment on both islands with snake replicas made of clay. These results clearly indicated a strong inter-island difference in predator attack rates where snake replicas that resembled coral snakes received protection in Trinidad but not in Tobago. Color patterns from museum specimens confirmed that E. ocellatus is indeed a poor mimic of coral snakes in many respects, especially in regards to the relative proportions of colors and the lack of discrete band. This implies that the classic coral snake mimicry adaptation has been degraded in this species. Field experiment revealed that E. ocellatus replicas were not protected from predator attacks on Tobago (where no coral snakes occur) compared to controls. However, on Trinidad (where coral snakes do occur) we found the expected lower attack rate on coral snake and mimic replicas compared to controls. Thus, E. ocellatus does not just look like a poor mimic to human eyes, its predators show no evidence of avoiding it.

Further, a molecular phylogenetic analysis of the ancestry of E. ocellatus revealed that this poor coral snake mimic is deeply nested in a clade of good coral snake mimics. Therefore the lack of coral snakes on Tobago altered the selective environment such that the coral snake mimicry adaptation was no longer advantageous. The failure to maintain this ancestral feature in allopatry provides a compelling example of how losses of complex adaptations can occur.

Citation
Hodson EE, Lehtinen RM. 2017. Diverse Evidence for the Decline of an Adaptation in a Coral Snake Mimic. Evolutionary Biology. 2017:1-0.

Monday, May 22, 2017

The last European varanid

The Desert Monitor, Varanus griseus is the extant species
with the closest distribution to Europe today
In a recent paper, Georgalis et al. (2017) report the remains of a varanid lizard from the middle Pleistocene of the Tourkobounia 5 locality near Athens, Greece. The new fossil material comprises cranial elements only (one maxilla, one dentary, and one tooth) and is attributed to the monitor lizard genus Varanus, the genus to which all European Neogene varanid remains have been assigned. Previously, the most recent undisputed varanid from Europe had been recovered from upper Pliocene sediments. The new Greek fossils, therefore, constitute the most recent records of monitor lizards from the continent. Despite being incomplete, this new material enhances our understanding of the cranial anatomy of the last European monitor lizards and is clearly not referable to any of the extant species such as Varanus griseus or Varanus niloticus - the only species that could be taken into consideration on a present-day geographic basis. However, these fossils could represent a survivor of the monitor lizards of Asian origin that inhabited Europe during the Neogene. Varanids first appear in the European fossil record during the Eocene. They are entirely absent from the European Oligocene faunas but appear again in the fossil record after the early Miocene. It is possible the European Paleogene varanids were victims of the Grande Coupure. The Grande Coupure refers to a break or change in faunal continuity about 33.5 MYA and marks the the end of the Eocene assemblages of mammals, with the arrival of Asian species in Europe. The authors note that on the basis of the available data this cannot be demonstrated with certainty. All of the Neogene European varanids appear to be members of Varanus, and they seem to have dispersed into Europe in the early Miocene. In fact, the earliest evidence of the genus on the European continent is recorded in the early Miocene of Spain. Whether these early Miocene immigrants originated directly from Africa or have Asian affinities cannot be demonstrated with certainty. The occurrence of Varanus-like forms in the late Eocene and early Oligocene of Egypt favors an African origin, but the Asian record is too weak to offer any insights. The fact that the maxilla from Tourkobounia 5 does not show any relationship with extant African taxa (V. albigularis, V. exanthematicus, V. griseus, V. niloticus, V. ornatus) suggests Asian affinities, as already reported for the extinct Varanus amnhophilis from the late Miocene of Samos. Whatever their exact origin, monitor lizards rapidly achieved a wide distribution throughout Europe during the Miocene. Fossils attributed to this genus have been described from localities in Austria, Germany, Greece, Hungary, Italy, Moldova, Portugal, Romania, Spain, and the Ukraine.

Citation

Georgalis, G. L., A. Villa, and M. Delfino. 2017. The last European varanid: demise and extinction of monitor lizards (Squamata, Varanidae) from Europe. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1301946.

Sunday, May 21, 2017

Some monitor lizards have not recovered from the introduction of the cane toad

Varanus panoptes Image credit: Greg Hume

The impact of invasive species is often underestimated by many. However, invasives can trigger trophic cascades in animal communities but published cases documenting the results of removing top predators are extremely rare. An exception is the invasive cane toad (Rhinella marina) in Australia, which has caused severe population declines in monitor lizards, triggering trophic cascades that facilitated dramatic and sometimes unexpected increases in several prey of the predators, including smaller lizards, snakes, turtles, crocodiles, and birds. Persistence of isolated populations of predators with a decades-long co-existence with toads suggests the possibility of recovery, but alternative explanations are possible. In a new paper, Doody et al. (2017)  note that confirming predator recovery requires longer-term study of populations with both baseline and immediate post-invasion densities. The authors had previously quantified the short-term impacts of the invasive cane toads over seven years at two sites in tropical Australia. In the new paper, they test the hypothesis that predators have begun to recover by repeating the study 12 years after the initial toad invasion. The three predatory lizards (Varanus panoptes, V. mertensi, V. mitchelli) that experienced 71-97% declines in the short-term study showed no sign of recovery, and indeed a worse fate. Two of the three species  (Varanus panoptes and V. mitchelli) were no longer detectable in 630 km of river surveys, suggesting local extirpation. Two mesopredators that had increased markedly in the short-term due to the above predator losses showed diverse responses in the medium-term; a small lizard species increased by about 500%, while populations of a snake species showed little change. Their results indicate a system still in ecological turmoil, having not yet reached a ‘new equilibrium’ more than a decade after the initial invasion; predator losses due to this toxic invasive species, and thus downstream effects, were not transient. Given that cane toads have proven too prolific to eradicate or control, we suggest that recovery of impacted predators must occur unassisted by evolutionary means: dispersal into extinction sites from surviving populations with alleles for toxin resistance or toad avoidance. Evolution and subsequent dispersal may be the only solution for a number of species or communities affected by invasive species for which control is either prohibitively expensive, or not possible.

Citation
Doody JS, Rhind D, Green B, Castellano C, McHenry C, Clulow S. 2017. Chronic effects of an invasive species on an animal community. Ecology. 2017 May 6.



Norisophis begaa, a new basal snake from the early Cretaceous

Image credits: Tyler Keillor (sculpture) and Ximena Erickson
(original photography); modified by Bonnie Miljour. 
Klein et al. (2017) note that fossil snakes are well represented in the Upper Cretaceous of northern Africa (99.7 to 94.3 MYA), with material known from Morocco, Sudan, Egypt, Libya, Algeria, and Niger. The Moroccan Kem Kem beds have yielded a particularly diverse snake assemblage, with members of the families Simoliophiidae, Madtsoiidae, ?Nigerophiidae and several unnamed taxa co-occurring. These fossils are important for our understanding of the early evolutionary history of snakes, and may shed light on the ecology and initial diversification of basal snakes. Klien and colleagues (2017) describe a new taxon, Norisophis begaa, from the Kem Kem beds of Begaa, at  at Aferdou N'Chaft, in southeast Morocco. Although known only from vertebrae, the unique appearance of the fossils adds to our knowledge regarding the early history the snake fauna of the northern Africa's Late Cretaceous. The vertebrae are characterised by a marked interzygapophyseal constriction, parazygantral foramina, an incipient prezygapophyseal process, and an anterio-posteriorly short centrum. Several characteristics shared with Najash, Seismophis, Madtsoiidae, and Coniophis suggest that Norisophis is a stem ophidian. N. begaa further increases the diversity and disparity of snakes within the Kem Kem beds, supporting the hypothesis that Africa was a mid-Cretaceous hotspot for snake diversity.

Citation
Klein CG, Longrich NR, Ibrahim N, Zouhri S, Martill DM. 2017. A new basal snake from the mid-Cretaceous of Morocco. Cretaceous Research. 2017 Apr 30;72:134-41.

The rediscover of some Brazilian anoles and their biogeographic significance

Brazil's Atlantic Forest has montane ranges with an exceptionally high diversity of endemic amphibians and reptiles. Connections between this area and other areas of South America have been proposed as reason. In a new paper Ivan Prates and colleagues report the the rediscovery of Anolis nasofrontalis and Anolis pseudotigrinus, two mainland species from the Brazilian Atlantic Forest that were not reported for more than 40 years.

Coloration in life of Anolis nasofrontalis (A, B) and A. pseudotigrinus (C, D). In A, inset shows the black 
throat lining of A. nasofrontalis. Photographed specimens are females. Ivan Prates

By combine new genetic data with published sequences of species in the Dactyloa clade of Anolis they were able to investigate the phylogenetic relationships of A. nasofrontalis and A. pseudotigrinus, as well as estimate divergence times from their closest relatives.  The phylogenetic analysis recovered six main clades within Dactyloa, five of which were previously referred to as species series (aequatorialis, heterodermus, latifrons, punctatus, roquet). A sixth clade clustered A. nasofrontalis and A. pseudotigrinus with A. dissimilis from western Amazonia, A. calimae from the Andes, A. neblininus from the Guiana Shield, and two undescribed Andean taxa. This allowed them to  define a sixth species series within Dactyloa: the neblininus series. Close phylogenetic relationships between highly disjunct, narrowly-distributed anoles suggest that patches of suitable habitat connected the southern Atlantic Forest to western South America during the Miocene, in agreement with the age of former connections between the central Andes and the Brazilian Shield as a result of Andean orogeny. The data also support the view of recurrent evolution (or loss) of a twig anole-like phenotype in mainland anoles association with montane regions.

The neblininus series is composed of narrowly-distributed species that occur in mid-elevation sites, or adjacent habitats in the case of A. dissimilis, separated by large geographic distances. This pattern suggests a complex biogeographic history involving former patches of suitable habitat between regions, followed by habitat retraction and extinction in the intervening areas. In the case of A. nasofrontalis and A. pseudotigrinus, for instance, past forest corridors may explain a close relationship with the western Amazonian A. dissimilis. Atlantic and Amazonian rainforests are presently separated by open savannas and shrublands, yet geochemical records suggest that former pulses of increased precipitation and wet forest expansion have favored intermittent connections between them. These connections may have also been favored by major landscape shifts as a result of Andean orogeny, such as the establishment of the Chapare buttress, a land bridge that connected the central Andes to the western edge of the Brazilian Shield during the Miocene.

During morphological examinations of A. nasofrontalis and A. pseudotigrinus, it became apparent that these two species are not very different from Caribbean twig anoles, with whom they share short limbs and cryptic coloration. These features are also present in other, distantly-related mainland anoles, such as A. euskalerriari, A. orcesi, A. proboscis, and A. tigrinus. Phylogenetic relationships support that a twig anole-like phenotype was acquired (or lost) independently within Dactyloa, perhaps as a result of adaptive convergence. Alternatively, this pattern may reflect the conservation of an ancestral phenotype. In the former case, an apparent association with South American mountains is intriguing.

Unfortunately, natural history data from A. nasofrontalis and A. pseudotigrinus are lacking. It is currently unclear whether they  exhibit the typical ecological and behavioral traits that characterize the Caribbean twig anole ecomorph, such as active foraging, slow movements, infrequent running or jumping, and preference for narrow perching surfaces.

Citations

Prates I, Melo-Sampaio PR, de Oliveira Drummond L, Teixeira M, Rodrigues MT, Carnaval AC. 2017. Biogeographic links between southern Atlantic Forest and western South America: rediscovery, re-description, and phylogenetic relationships of two rare montane anole lizards from Brazil. Molecular Phylogenetics and Evolution. 2017 May 11.

Prates, I. 2017. Legendary Brazilian Anoles Rediscovered. http://www.anoleannals.org/2017/05/14/legendary-brazilian-anoles-rediscovered/


Friday, May 19, 2017

First warm blooded vertebrate, Ophiacodon?

Ophiacodon mirus. Image Credit ru.wikapedia

People who like watching lizards often get the best opportunity to do so in the morning, as they can usually be found sunbathing at this time of day. This is because they rely on an external energy supply to reach their operating temperature. However, mice and other mammals make themselves nice and cozy in a different way: they burn calories and can even keep themselves warm during a bitterly cold winter's night.

Mammals are thus referred to as warm-blooded. Until now, it was thought that the "body heater" was invented in four-legged land animals around 270 million years ago. "However, our results indicate that warm-bloodedness could have been created 20 to 30 million years earlier," explains Prof. Martin Sander from the Steinmann Institute for Geology, Mineralogy and Paleontology at the University of Bonn.

For long-extinct animals, it is naturally not possible to simply determine body temperature using a thermometer. However, warm-bloodedness leaves behind tell-tale signs in fossils. It not only means that the animal is not reliant on the ambient temperature, but also enables faster growth. "And this is shown in the structure of the bones," explains Sander.

Bones are composites of protein fibers, collagen, and a biomaterial, hydroxyapatite. The more orderly the arrangement of the collagen fibers, the more stable the bone, but the more slowly it normally grows as well. The bones of mammals thus have a special structure. This allows them to grow quickly and yet remain stable. "We call this bone form fibrolamellar," says the paleontologist.

Together with his PhD student Christen D. Shelton (now at the University of Cape Town), the scientist looked at humerus bones and femurs from a long-extinct land animal: the mammal predecessor Ophiacodon. This lived 300 million years ago. "Even in Ophiacodon, the bones grew as fibrolamellar bones," says Sander to summarize the analysis results. "This indicates that the animal could already have been warm-blooded."

Ophiacodon was up to two meters long, but otherwise resembled today's lizards -- and not without good reason: mammals and reptiles are related; they thus share a predecessor. In the family tree, Ophiacodon is very close to the place where these two branches separate.

However, lizards, turtles and other reptiles living today are cold-blooded. Until now, it has been assumed that this was the original form of the metabolism -- i.e. that the shared ancestor of both animal groups was cold-blooded. Warm-bloodedness would thus be a further development, which arose over the course of mammalian evolution.

However, Ophiacodon appears a very short time after the division between mammals and reptiles. "This raises the question of whether its warm-bloodedness was actually a completely new development or whether even the very first land animals before the separation of both branches were warm-blooded," says Sander. That is just speculation. However, if this theory is correct, we would have to drastically correct our image: the first reptiles would then also have been warm-blooded -- and would have only discarded this type of metabolism later.



Citation
Shelton CD, Sander PM. 2017. Long bone histology of Ophiacodon reveals the geologically earliest occurrence of fibrolamellar bone in the mammalian stem lineage. Comptes Rendus Palevol, 2017; DOI: 10.1016/j.crpv.2017.02.00

Tuesday, April 11, 2017

Crack pots, insanity, and some really sick human beings

Snakes provide a variety of ecosystem services, not the least of which is rodent control. This is a free service provide by nature. However, like much of what is free, Republicans insist on privatizing it so somebody can make a profit.

Arizona HB2022 failed on a tie vote yesterday (April 10, 2017). The bill, if passed, would have allowed citizens to shoot "snake shot" within city limits in the State of Arizona. The Arizona Daily Star today (April 11) attributes the failure of the bill to a letter from Mike Cardwell an employee of the San Bernadino County Sherrif's office (California) and a herpetologist. Kudo's to Mike for sending the letter. The Cardwell letter included the following "The bottom line when it comes to destroying small animals like rattlesnakes is that that gun fire presents a much greater danger to by-standers than the snake itself."

Where is the Hantavirus when you need?  Oh, the snakes are controlling the rodents that carry it! The New Mexico Department of Health announced April 7th that a 54-year-old man from San Juan County has died of Hantavirus Pulmonary Syndrome (HPS). This is the second case of HPS confirmed in New Mexico this year. Snakes control rodents that carry this virus and reduce the probability that it will be transmitted to humans.

Just so you understand where this kind of proposed legislation comes from - here is the argument for the law, made by Chris Eger, at Guns.com. The comments that accompany this post are eye-opening.

A House measure advancing through committee would allow the use of specialty ammo inside Arizona cities for snakes and rats but is drawing fire from animal rights groups.
The bill, proposed earlier this month in the state House, has been winding its way through hearings and has gotten an initial nod from lawmakers, though its sponsor cautions it is not an animal regulation proposal.
“It’s a firearms bill,” said Rep. Jay Lawrence, R-Scottsdale. “It’s not a bill that deals with harming snakes or rats or any other vermin, it merely is a firearms bill.”
Lawrence’s measure, HB 2022, would amend state law to allow the use of rat or snake shot to control pests. The cartridges, instead of using a solid bullet, utilize a plastic cap or shell that holds a quantity of small diameter shot. The bill’s language only allows for .22 caliber shot rounds with pellets 1.3mm or less in diameter.
Currently, only the use of blanks is allowed within city limits to control pests.
Not all are impressed by the bill, especially reptile advocates who point out there are at least four species of endangered snakes at large in Arizona.
Russ Johnson of the Phoenix Herpetological Society told local media the proposal is fraught with pitfalls.
“Do we really want people shooting guns in the city limits next to houses?” said Johnson. “You’re talking about shooting rats. So you’re shooting on your rooftop, so you got bird shot spraying everywhere. OK, if you’re shooting a snake, you’re pointing down. You’re gonna get a ricochet even though it’s pellet.”
HB 2022 has passed both the JPS and Rules committees.
Filed Under: Ammunition, Politics & 2nd Amendment


Monday, April 10, 2017

Logging & Leatherbacks


Leatherback turtle hatchlings. Photo Credit: Juan Patiño
 Debris from logging in tropical forests is threatening the survival of hatchling leatherback turtles and the success of mothers at one of the world's most important nesting sites in Colombia.

New research by the University of Exeter and the Doñana Biological Station in Seville, Spain, has found that debris on beaches caused by logging activity is impacting both young turtles and their mothers during the key periods of their life cycles.

Leatherbacks are at particular risk of being caught up in fishing nets and longlines as bycatch, because they are migratory, travelling long distances worldwide.

Many breeding sites are already under pressure from tourism.

But now, research published in the journal Marine Ecology Progress Series has revealed that the logging is an additional, previously underestimated threat.

To nest and breed successfully, females must be able to cross the sandy beaches to dig their nest to successfully incubate their eggs.

In turn, hatchlings must be able to cross the sand unaccompanied to reach the water.

Researchers found that the beach debris hindered this movement.The team monitored 216 turtles, comparing their activity in areas with high amounts of debris to low amounts, in a globally significant nesting site in Colombia.
 
They also manipulated the amount of debris to see how it changed behavior.

They found that females which nested in areas with higher amounts of debris were spent more time building their nest and tended to do so closer to the shoreline.

This meant they were more vulnerable to flooding, which puts their eggs at risk.

Some females were even wounded in the process.

The debris also meant it took longer for hatchlings to reach the sea, increasing their chance of being eaten by predators and meaning they had to expend more energy, making them more vulnerable.

Professor Brendan Godley, director of the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus in Cornwall, is a co-author on the research.

He said: "Leatherback turtles are already under immense pressure, from fisheries bycatch and are also one of the species prone to ingesting marine plastic litter.

"Our research clearly indicates that logging presents another threat.

"It is now paramount that beach clean-up operations are built into logging activities to prevent further damage to this species."

Dr Adolfo Marco Llorente, of the Doñana Biological Station, said: "Although logging debris does not affect rates of nesting, it has a significant impact on where and how nests are built, which negatively affects both mothers and hatchlings.

"This is on a scale that could lead over time to reduction of the overall population.

"Simple measures could make a real difference, such as repositioning organic waste areas, or salvaging the wood debris as an energy source.

"It's also essential that logging practices that reduce the impact on the marine environment are implemented."



 Patino-Martinez J, Godley BJ,  Quiñones L,  Marco A. 2017.  Impact of tropical forest logging on the reproductive success of leatherback turtles. Marine Ecology Progress Series, 569: 205 DOI: 10.3354/meps12064

Friday, April 7, 2017

Lowland amphibians are at higher risk from future climate warming.


A new study of Peruvian frogs living at a wide variety of elevations -- from the Amazon floodplain to high Andes peaks -- lends support to the idea that lowland amphibians are at higher risk from future climate warming.

That's because the lowland creatures already live near the maximum temperatures they can tolerate, while high-elevation amphibians might be more buffered from increased temperatures, according to a study by University of Michigan ecologist Rudolf von May and his colleagues published online April 6 in the journal Ecology and Evolution.

Previous studies have suggested that lowland reptiles and amphibians are especially vulnerable to climate warming. But in most cases, those conclusions were based on computer modeling work that incorporated a limited amount of field data.

"Understanding how species respond to climatic variation is critical for conserving species in future climatic conditions. Yet for most groups of organisms distributed in tropical areas, data about species' critical thermal limits are limited," said von May, a postdoctoral researcher in the U-M Department of Ecology and Evolutionary Biology.

"I think the contribution of our study is that it focuses on a group of closely related frog species distributed along a single montane gradient and that it includes empirical data on species' tolerance to heat and cold, as well as air temperatures measured along the same gradient."

In the process of conducting the study, which involved more than two years of fieldwork, von May and his colleagues identified three previously unknown frog species. Those newly discovered species will be described separately in a series of journal articles.

The elevational-gradient study focused on the thermal ecology and evolution of 22 species of land-breeding frogs, which are also known as terrestrial-breeding frogs, in southern Peru's Manu National Park and surrounding areas. Sampled elevations ranged from the Amazon River floodplain, at 820 feet above sea level, to 12,000-foot Andes Mountains peaks.

The region in and around Manu National Park is known for long-held records of biodiversity including more than 1,000 species of birds -- about 10 percent of the world's bird species -- and more than 1,200 species of butterflies. In addition, the park contains an estimated 2.2 percent of the world's amphibians and 1.5 percent of its reptiles.

While most frogs lay eggs in water, terrestrial-breeding frogs use a specialized reproductive mode called direct development: A clutch of embryos hatch directly into froglets; there are no free-living tadpoles. Terrestrial-breeding frogs form a diverse group that can exploit a wide variety of habitats, as long as those locations contain sufficient moisture.

In the study, the researchers looked at how closely related frog species differ in their elevational distribution and their tolerance to heat and cold in a region of the tropical Andes where temperature increase is predicted to be detrimental for most species.

"These measurements were taken in order to determine whether tropical frogs could take the heat -- or cold -- predicted for tropical regions as a result of climate change," von May said.

The researchers found that the frogs' tolerance to heat varied from 77 degrees Fahrenheit to 95 degrees and that, as expected, highland species tolerated much lower temperatures than lowland species.

Frogs living in high-elevation grasslands tolerated near-freezing temperatures, which they experience during the dry season, as well as moderately high temperatures, which they may experience during sunny days.

When considering the temperature of the microhabitats in which the frogs live, the results suggest tropical lowland species live close to their thermal limit. Amphibians living at high elevation might be more buffered from future temperature increases because the highest temperatures they can tolerate are farther away from the maximum temperatures that they regularly experience in the wild.

Von May is the first author of the Ecology and Evolution paper, "Divergence of thermal physiological traits in terrestrial breeding frogs along a tropical elevational gradient."

Citation
Rudolf von May, Alessandro Catenazzi, Ammon Corl, Roy Santa-Cruz, Ana Carolina Carnaval, Craig Moritz. Divergence of thermal physiological traits in terrestrial breeding frogs along a tropical elevational gradient. Ecology and Evolution, 2017; DOI: 10.1002/ece3.2929



Wednesday, March 15, 2017

Cobras - Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting

Bryan Frye and a cobra.
A University of Queensland-led international study has revealed how one of the world's most feared types of snakes -- cobras -- developed their potent venom.

Associate Professor Bryan Fry of UQ's School of Biological Sciences said cobras were killers in Africa and Asia, and caused crippling social and economic burdens through the number of survivors who needed amputations due to the snake's flesh-eating venom.

"While we knew the results of their venom, how the cobra's unique defensive venom evolved remained a mystery until now," he said.

"Our study discovered the evolutionary factors shaping not only cobra venom, but also the ornate markings on their hoods, and the extremely bright warning colourings present in some species."

The research team studied 29 cobra species and related snakes, finding that the flesh-destroying venom first evolved alongside the broad hoods that make cobras so distinctive.

Dr Fry said further increases in the potency of the toxins subsequently occurred parallel to their warning strategies such as hood markings, body banding, red colouring and spitting.

"Their spectacular hoods and eye-catching patterns evolved to warn off potential predators because unlike other snakes, which use their venom purely for predation, cobras also use it in defence," he said.

"For the longest time it was thought that only spitting cobras had these defensive toxins in high amounts in their venoms, however we've shown that they are widespread in cobras.

"These results show the fundamental importance of studying basic evolution and how it relates to human health."

Dr Fry said the next step in the team's research was to conduct broad antivenom testing.

"Globally, snakebite is the most neglected of all tropical diseases and antivenom manufacturers are leaving the market in favour of products that are cheaper to produce and have a bigger market," he said.

"Antivenom is expensive to make, has a short shelf life and a small market located in developing countries.

"Therefore, we need to do further research to see how well those remaining antivenoms neutralise not only the toxins that kill a person, but also those that would cause a severe injury."

He said there may also be a benefit to this research in cancer treatment.

"Any kind of compound that selectively kills cells could be a good thing," Dr Fry said.

"These chemicals may lead to new cancer treatments if we can find ones that are more potent to cancer cells than normal healthy cells.

"Cobras are a rich resource of novel compounds in this way so there may ultimately be a silver lining to this very dark cloud."


Citation

Panagides N, Jackson TN, Ikonomopoulo MP. Arbuckle K, Pretzler R, Yang DC, Ali SA, Koludarov I, Dobson J, Sanker B, Asselin A, Santana RC, Hendrikx I, van der Ploeg H. Tai-A-Pin J, van den Bergh R. Kerkkamp HM, Vonk FJ, Naude A, Strydom MA, Jacobsz L, Dunstan N. Jaeger M, Hodgson WC, Miles J, Fry BG. 2017 How the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting. Toxins  9, 103.

Monday, March 13, 2017

Hypsiboas punctatus, the first fluorescent frog

Before and after. The polka-dot tree frog in natural light
 (top) and under UV (bottom.)Photo credit: Julian Faivovich
 & Carlos Taboada 
The first fluorescent frogs have been discovered in South America. The green fluorescence is due to a compound found in the lymph and skin glands of the polka-dot treefrog (Hypsiboas punctatus). At twilight, the phenomenon enhances the frogs’ brightness and may help them communicate with each other.

Fluorescence has previously been reported in fish, scorpions and birds, but never amongst the 7000 plus species of amphibians. The blue–green glow of the polka-dot tree frog was observed when they were under UV light and is linked to a new fluorescent compound, not previously known in nature. The compound absorbs light in the violet–ultraviolet region and emits blue–green light. Time-of-flight mass spectrometry showed that the main fluorescent compound was the molecule Hyloin-L1. NMR revealed an N-methyl-dihydroisoquinolinone core.

‘It is basically a benzamide with a methoxy group added on, which makes the absorption band fall on the edge of the visible spectrum,’ notes Andrew Beeby at Durham University, UK, who was not involved in the study. He adds that this ‘DayGlow frog’ adds to our growing awareness of bioluminescence. The isoquinolinone structure has never before been described in any animals, only in plants. The chromophore seems to be the cyclic benzamide.

‘This is very different from fluorophores found in other vertebrates, which are usually proteins or polyenic chains,’ says author Maria Gabriela Lagorio, a photochemist at the University of Buenos Aires, Argentina. ‘The chromophore itself is well known, but the class of the secondary compound is completely new,’ adds co-author Norberto Peporine Lopes, a natural product chemist at the University of São Paulo in Brazil.

Hyloin L-1 (H-L1) is the molecule that is principally responsible for the polka-dot tree frogs’ fluorescence, although the other molecules pictured also contribute Biologist Karen Carleton at the University of Maryland notes that like many colourful compounds, ‘it contains lots of carbon–carbon double bonds with lots of π electronics that can easily be excited at visible wavelengths. It is also similar to a compound like 11-cis retinal, which is the chromophore that our eye uses to absorb light.’

The discovery is a bolt out of the blue for most in the field. ‘We were not expecting this bio-fluorescence. It was an incredible surprise,’ says Lopes. He suspects the frog, which has translucent skin, uses the phenomenon to communicate. Lagorio agrees: ‘Amphibian species have photoreceptors in their eyes maximally attuned to blue and green vision, so we expect that these compounds enhance the brightness of these frogs under conditions of twilight.’ The team has now begun examining the polka-dot’s relatives. ‘We expect that this will be a more universal phenomenon with perhaps 100 or 200 species showing this property,’ says Lopes.

‘It would be interesting to investigate if [fluorescence] has a role in species recognition, or whether it facilitates the formation of couples,’ notes Bibiana Rojas, ecologist at the University of Jyväskylä, Finland. ‘Fluorescence would be potentially very useful in a noisy environment and in a habitat with dense foliage, as it would make individuals brighter.’

Citation

Taboada C, Brunetti AE, Pedron FN, Neto FC,  Estrin DA, Bari SE, Chemes LB,  Lopes NP, Lagorio MG, Faivovich J. 2017. Naturally occurring fluorescence in frogs. PNAS 2017 doi:10.1073/pnas.1701053114

Saturday, March 11, 2017

A new homalopsid snake from Myanmar

Gyiophis salweenensis Photo credit. Evan Quah
The 54th species of homalopid snake has been described by Quah et al. (2017). The new species, Gyiophis salweenensis was described from the lowlands of Mawlamyine District in Mon state, southeastern Myanmar. The authors suggest that Gyiophis salweenensis  is presumed to be closely related to G. maculosa Blanford and G. vorisi Murphy based on the similarities in scales and coloration but can be separated from G. maculosa by the shape of its first three dorsal scale rows that are square, ventral scale pattern that lacks a central spot, and a faint stripe on dorsal scale rows 1–4. It can be further distinguished from G. vorisi by its lower number of ventral scales (129 vs. 142–152), lower number of subcaudals (30/29 vs. 41–58), narrow rostral scale, and having more rows of spots on the dorsum (four vs. three). A preliminary molecular analysis using 1050 base pairs of cytochrome b (cytb) recovered G. salweenensis  as the sister species to the Chinese Mud Snake (Myrrophis chinensis). G. maculosa and G. vorisi were unavailable for the analysis. The discovery of G. salweenensis sp. nov. highlights the need for more surveys into the herpetological diversity of eastern Myanmar which remains very much underestimated.

Citation
Quah ES, Grismer LL, L Jr PE, Thura MK, Zin T, Kyaw H, Lwin N, Grismer MS, Murdoch Ml. 2017. A new species of Mud Snake (Serpentes, Homalopsidae, Gyiophis Murphy & Voris, 2014) from Myanmar with a first molecular phylogenetic assessment of the genus. Zootaxa. 4238(4):571-82.

Wednesday, February 22, 2017

Tiny frogs from the Western Ghats

Seven new species discovered from the Western Ghats. A. Radcliffe's Night Frog (Nyctibatrachus radcliffei), B. Athirappilly Night Frog
 (Nyctibatrachus athirappillyensis), C. Kadalar Night Frog (Nyctibatrachus webilla), D. Sabarimala Night Frog (Nyctibatrachus sabarimalai),
 E. Vijayan's Night Frog (Nyctibatrachus pulivijayani), F. Manalar Night Frog (Nyctibatrachus manalari), G. Robin Moore's Night Frog.
[(D-G. Size of the miniature species in comparison to the Indian five-rupee coin (24 mm diameter)]. Photo Credit: SD Biju
Scientists from India have discovered seven new frog species belonging to the genus Nyctibatrachus, commonly known as Night Frogs. This find is a result of five years of extensive explorations in the Western Ghats global biodiversity hotspot in India. Four out of seven of the new species are miniature-sized frogs (12.2-15.4 mm), which can comfortably sit on a coin or a thumbnail. These are among the smallest known frogs in the world.

Unlike other frogs in the genus that are predominantly stream dwelling, the new miniature frogs were found under damp forest leaf litter or marsh vegetation. Scientists were surprised by the relative abundance of these previously unknown species at their collection localities. "In fact, the miniature species are locally abundant and fairly common but they have probably been overlooked because of their extremely small size, secretive habitats and insect-like calls," says Sonali Garg who undertook this study as part of her PhD research at University of Delhi.

In the lab, the newly sampled frogs were confirmed as new species by using an integrated taxonomic approach that included DNA studies, detailed morphological comparisons and bioacoustics. Evidence from these multiple sources confirmed that the diversity of Night frogs is higher than previously known and particularly remarkably for the miniaturized forms. Previously, the Night Frog genus composed of 28 recognized species of which only three were miniature-sized.

Now the total number of known Nyctibatrachus species has increased to 35, of which 20 percent are diminutive in size. This frog genus is endemic to the Western Ghats of India and represents an ancient group of frogs that diversified on the Indian landmass approximately 70-80 million years ago.

The discovery of several new species of ancient origin can provide useful insights into the evolution of endemic frog lineages in the Western Ghats, which is a leading amphibian hotspot. The past decade has witnessed an exponential increase in the number of new amphibian species described from this region. Of the total new species of amphibians (1581) described globally between the years 2006-2015, the highest number were from the Brazilian Atlantic Forest (approximately 182) followed by the Western Ghats-Sri Lanka biodiversity hotspot (approximately 159), with 103 species described alone from the Western Ghats region.

However, the future of many of the new species may be bleak. All the newly described species are currently known only from single localities in the southern Western Ghats, and some lie outside Protected areas. Researchers found the Radcliffe's Night frog and the Kadalar Night Frog inside private or state-owned plantation areas facing threats such as habitat disturbance, modification and fragmentation. The Athirappilly Night Frog was found in close vicinity to the Athirappilly waterfalls and the Sabarimala Night Frog near the Sabarimala pilgrimage centre, both of which are disturbed by anthropogenic activities. "Over 32 percent, that is one-third of the Western Ghats frogs are already threatened with extinction. Out of the seven new species, five are facing considerable anthropogenic threats and require immediate conservation prioritization," says Prof SD Biju, who led the new study and has also formally described over 80 new species of amphibians from India

Citation
Sonali Garg, Robin Suyesh, Sandeep Sukesan, SD Biju. Seven new species of Night Frogs (Anura, Nyctibatrachidae) from the Western Ghats Biodiversity Hotspot of India, with remarkably high diversity of diminutive forms. PeerJ, 2017; 5: e3007 DOI: 10.7717/peerj.3007

Tuesday, February 21, 2017

Phylogenetics of Kingsnakes in the Lampropeltis getula Complex, in Eastern North America

Distribution of kingsnakes in the Lampropeltis getula complex in North America:
 (A) Lampropeltis californiae (banded); (B) Lampropeltis holbrooki;
 (C) Lampropeltis nigra; (D) Lampropeltis getula getula; (E) Lampropeltis getula 
“sticticeps”; (F) Lampropeltis getula floridana; (G–I) Lampropeltis getula 
meansi (patternless, striped, and wide-banded, respectively); (J) Lampropeltis 
splendida; (K) Lampropeltis getula nigrita; (L) Lampropeltis californiae 
(striped). Distributions are modified after Conant and Collins (1998),
 Krysko (2001), Stebbins (2003), Krysko and Judd (2006), and 
Pyron and Burbrink (2009a, 2009b).
Kingsnakes of the Lampropeltis getula complex range throughout much of temperate and subtropical North America; along the Pacific coast from Oregon southward to the Mexican Plateau, and eastward to New Jersey and southward to Florida. Kingsnakes of this species complex are extremely variable in color pattern, and therefore, along with their mostly docile disposition, are easily recognizable and very popular in the pet trade.The distinct morphology and color patterns found in the Lampropeltis getula complex, along with its transcontinental geographic distribution and occasional disjunct populations across the North American
Distribution and locations of samples sequenced for kingsnakes 
of the Lampropeltis getula complex in eastern North America: yellow 
dots = Lampropeltis getula floridana from Florida peninsula; blue dots = 
Lampropeltis getula getula from the Atlantic coast; red dots = Lampropeltis 
getula meansi from the Eastern Apalachicola Lowlands in the Florida 
panhandle; gray dots = morphological intermediates between L. g. floridana
 and L. g. getula; and coral dots = morphological intermediates between 
L. g. getula and L. g. meansi. Green and pink polygons refer to Lampropeltis
 nigra and Lampropeltis holbrooki, respectively, on the western side of the 
Appalachian Mountains. Distributions are modified after Conant and 
Collins (1998), Krysko (2001) using multi-locus phylogeny, 
and Krysko and Judd (2006) using morphology.
landscape make a fascinating subject for phylogeography. In a new paper Krysto et al (2017) expanded the sample from the getula complex and add a nuclear DNA locus to the molecular data set  used previously to hypotheses distinct genetic lineages. They use genetic and ecological methods to test previous hypotheses of distinct evolutionary lineages by examining 66 total snakes for: analyzing phylogeographic structure using 2 mtDNA loci and 1 nuclear locus; estimating divergence dates and historical demography among lineages in a Bayesian coalescent framework, and; applied ecological niche modeling (ENM). The molecular data and ENMs illustrate that three previously recognized subspecies in the eastern United States comprise well-supported monophyletic lineages that diverged during the Pleistocene. The geographic boundaries of these three lineages correspond closely to known biogeographic barriers (Florida peninsula, Appalachian Mountains, and Apalachicola River) previously identified for other plants and animals, indicating shared geographic influences on evolutionary history. Them authors conclude that genetic, ecological, and morphological data support recognition of these 3 lineages as distinct species (Lampropeltis floridana, Lampropeltis getula, and Lampropeltis meansi).

Citation
Krysko KL, Nuñez LP, Newman CE, Bowen BW. Phylogenetics of Kingsnakes, Lampropeltis getula Complex (Serpentes: Colubridae), in Eastern North America. The Journal of heredity. 2017 Jan 24.

Saturday, February 18, 2017

Climatic and geographic predictors of life history variation in Eastern Massasauga, Sistrurus catenatus

A juvenile Eastern Massasauga. Photo credit: Eric Hileman.

A new study is bringing attention to a little known and imperiled rattlesnake that slithers among the wetlands in regions surrounding the Great Lakes.

The Eastern Massasauga rattler was once common in such states as Indiana and Illinois. Until recent years, it could still be found in Chicago's Cook County. But the reptile's range and numbers have been steadily declining. In 2016, the snake was listed as threatened under the U.S. Endangered Species Act.

In the new study, Northern Illinois University biological sciences professor Richard King and his former student Eric Hileman examine the life history of the Eastern Massasauga, revealing important local climate impacts on the snake that should be carefully weighed when developing conservation strategies.

"Our results provide evidence that climatic variation in the Great Lakes region strongly influences body size, individual growth rates and key aspects of reproduction," says Hileman, first author of the study published in PLOS ONE, a journal of the Public Library of Science. Hileman earned his Ph.D. in biological sciences from NIU in December and is now a postdoctoral fellow in biology at Trent University in Ontario, Canada.

Hileman, King and more than 40 co-authors gathered and synthesized more than a century of data on the snakes from study sites across the range of the Eastern Massasauga. Most of the data was culled from studies conducted from the mid-1990s forward at sites in Illinois, Indiana, Wisconsin, Michigan, Iowa, Ohio, Pennsylvania and New York, as well as Ontario, Canada.

The scientists found strong evidence for geographic variation in six of nine life-history variables. Among the findings:

The average body size of the snake and the size of its offspring increased with increasing mean annual precipitation, possibly because wetter climates yield greater prey abundance.

Litter sizes decreased with increasing mean temperature, and increased by one offspring for each 1.89-degree increase in latitude, even when maternal size was held constant.

"It's been rare to look within a species and show that these patterns exist," King says. "The study results demonstrate that a one-size-fits all conservation strategy is not appropriate. Rather, assessments of extinction risk and the design of management strategies need to account for geography."

The Eastern Massasauga snakes are generally found in wet prairies or sedge meadows, where the reptiles employ a sit-and-wait strategy to catch and feed on small mammals. Adult size ranges from about 2 feet to 2 ½ feet in length. While venomous, the snakes are not particularly aggressive or dangerous to work with.

"You're not likely to encounter them unless you're looking for them," King says. "It's easy to walk right by one. They're very cryptically colored to look like dead leaves and cattails, so they blend in exceedingly well."

The reptiles suffered habitat loss from extensive drainage of land for agriculture and development. As recently as the 1970s, some states had bounties on the snake.

With concerns over whether they would persist in the wild, the remaining snakes in Chicago's Cook County were taken into a captive breeding program in 2010, King says.

"In Illinois, they've nearly blinked out entirely," he adds. "We're probably down to one location in the southern part of the state that has a stable population. They seem to have stronger holds in Michigan and southern Ontario."

The study authors believe findings will aid Eastern Massasauga recovery efforts.

"The life-history parameter estimates will be essential for improving models related to extinction risk and climate change," Hileman says. "The results from these predictive models can subsequently be used to develop site-specific management strategies."


Citation

Eric T. Hileman, Richard B. King, John M. Adamski, Thomas G. Anton, Robyn L. Bailey, Sarah J. Baker, Nickolas D. Bieser, Thomas A. Bell, Kristin M. Bissell, Danielle R. Bradke, Henry Campa, Gary S. Casper, Karen Cedar, Matthew D. Cross, Brett A. DeGregorio, Michael J. Dreslik, Lisa J. Faust, Daniel S. Harvey, Robert W. Hay, Benjamin C. Jellen, Brent D. Johnson, Glenn Johnson, Brooke D. Kiel, Bruce A. Kingsbury, Matthew J. Kowalski, Yu Man Lee, Andrew M. Lentini, John C. Marshall, David Mauger, Jennifer A. Moore, Rori A. Paloski, Christopher A. Phillips, Paul D. Pratt, Thomas Preney, Kent A. Prior, Andrew Promaine, Michael Redmer, Howard K. Reinert, Jeremy D. Rouse, Kevin T. Shoemaker, Scott Sutton, Terry J. VanDeWalle, Patrick J. Weatherhead, Doug Wynn, Anne Yagi. Climatic and geographic predictors of life history variation in Eastern Massasauga (Sistrurus catenatus): A range-wide synthesis. PLOS ONE, 2017; 12 (2): e0172011 DOI: 10.1371/journal.pone.0172011

Sunday, February 12, 2017

Gliding lizards use the position of the sun to enhance social display

Sulawesi Lined Gliding Lizard (Draco spilonotus
showing the sun on the dewlap
Photo A. S. Kono/Wikamedia
In a recent paper, Klomp et al. describe how a gliding lizard in the genus Draco orient their body to the sun so that the light emphasizes their display. The following is the abstract from the paper.

Effective communication requires animal signals to be readily detected by receivers in the environments in which they are typically given. Certain light conditions enhance the visibility of colour signals and these conditions can vary depending on the orientation of the sun and the position of the signaller. We tested whether Draco sumatranus gliding lizards modified their position relative to the sun to enhance the conspicuousness of their throat-fan (dewlap) during social display to conspecifics. The dewlap was translucent, and we found that lizards were significantly more likely to orient themselves perpendicular to the sun when displaying. This increases the dewlap's radiance, and likely, its conspicuousness, by increasing the amount of light transmitted through the ornament. This is a rare example of a behavioural adaptation for enhancing the visibility of an ornament to distant receivers.

Citation
Klomp DA, Stuart-Fox D, Das I, Ord TJ. 2017. Gliding lizards use the position of the sun to enhance social display. Biology Letters. 2017 Feb 1;13(2):20160979.

Successful reintroduction of the critically endangered Antiguan racer Alsophis antiguae to offshore islands in Antigua, West Indies.

The following is an abstract recently published in the International Zoo Yearbook.

The Critically Endangered Antiguan racer Alsophis antiguae is endemic to Antigua and Barbuda (441 km2 area) but declined following the arrival of invasive mammals. By 1995, only an estimated 51 Antiguan racers survived on an offshore islet (Great Bird Island: 8·4 ha), many of which had injuries consistent with rat bites. To prevent extinction, a consortium of national and international organizations eradicated the Black rats Rattus rattus from Great Bird Island in 1995 and the snake population promptly doubled in size. The agencies then embarked on a program to eradicate invasive rats and, where present, Small Asian mongooses Herpestes javanicus from a further 14 islands around Antigua. The first reintroduction was carried out in November 1999, with ten wild racers translocated from Great Bird Island to Rabbi Island. Further reintroductions followed to Green Island (from October 2002) and York Island (from January 2008), bringing the total area of occupancy for racers to 63 ha. The translocated racers appeared to thrive in their new habitats and reproduced almost immediately. The reintroduction program was underpinned by field research, fundraising and an innovative education campaign to address prevailing negative attitudes towards snakes. While the Antiguan racer metapopulation has increased to > 1100 individuals in the wild, lasting success depends on Great Bird, Rabbit, Green and York Islands being fully protected from invasive mammals and harmful developments. To spread the risk, additional reintroduction sites must be identified.

Daltry JC, Lindsay K, Lawrence SN, Morton MN, Otto A, Thibou A. 2017. Successful reintroduction of the Critically Endangered Antiguan racer Alsophis antiguae to offshore islands in Antigua, West Indies. International Zoo Yearbook. 2017 

Wednesday, February 8, 2017

A new Fish-scale gecko in the genus Geckolepis

The new fish-scale gecko, Geckolepis megalepis, has the largest body scales of 
all geckos. This nocturnal lizard was discovered in the 'tsingy' karst formations 
in northern Madagascar. Photo Credit: F. Glaw
Many lizards can drop their tails when grabbed, but one group of geckos has gone to particularly extreme lengths to escape predation. Fish-scale geckos in the genus Geckolepis have large scales that tear away with ease, leaving them free to escape whilst the predator is left with a mouth full of scales. Scientists have now described a new species (Geckolepis megalepis) that is the master of this art, possessing the largest scales of any gecko.

The skin of fish-scale geckos is specially adapted to tearing. The large scales are attached only by a relatively narrow region that tears with ease, and beneath them they have a pre-formed splitting zone within the skin itself. Together, these features make them especially good at escaping from predators. Although several other geckos are able to lose their skin like this if they are grasped really firmly, Geckolepis are apparently able to do it actively, and at the slightest touch. And while others might take a long time to regenerate their scales, fish-scale geckos can grow them back, scar-free, in a matter of weeks.

This remarkable (if somewhat gruesome) ability has made these geckos a serious challenge to the scientists who want to study them. Early researchers described how it was necessary to catch them with bundles of cotton wool, to avoid them losing almost all of their skin. Today, little has changed, and researchers try to catch them without touching them if possible, by luring them into plastic bags. But once they are caught, the challenges are not over; identifying and describing them is even harder.

"A study a few years ago showed that our understanding of the diversity of fish-scale geckos was totally inadequate," says Mark D. Scherz, lead author of the new study and PhD student at the Ludwig Maximilian University of Munich and Zoologische Staatssammlung München, "it showed us that there were actually about thirteen highly distinct genetic lineages in this genus, and not just the three or four species we thought existed. One of the divergent lineages they identified was immediately obvious as a new species, because it had such massive scales. But to name it, we had to find additional reliable characteristics that distinguish it from the other species." A challenging task indeed: one of the main ways reptile species can be told apart is by their scale patterns, but these geckos lose their scales with such ease that the patterns are often lost by the time they reach adulthood. "You have to think a bit outside the box with Geckolepis. They're a nightmare to identify. So we turned to micro-CT to get at their skeletons and search there for identifying features." Micro-CT (micro-computed tomography) is essentially a 3D x-ray of an object. This method is allowing morphologists like Scherz to examine the skeletons of animals without having to dissect them, opening up new approaches to quickly study the internal morphology of animals.

By looking at the skeletons of the geckos, the team was able to identify some features of the skull that distinguish their new species from all others. But they also found some surprises; a species named 150 years ago, Geckolepis maculata, was confirmed to be different from the genetic lineage that it had been thought to be. "This is just typical of Geckolepis. You think you have them sorted out, but then you get a result that turns your hypothesis on its head. We still have no idea what Geckolepis maculata really is -- we are just getting more and more certain what it's not."

The new species, Geckolepis megalepis, which was described by researchers from the US, Germany, and Columbia in a paper published today in the open access journal PeerJ, is most remarkable because of its huge scales, which are by far the largest of any gecko. The researchers hypothesize that the larger scales tear more easily than smaller scales, because of their greater surface area relative to the attachment area, and larger friction surface. "What's really remarkable though is that these scales -- which are really dense and may even be bony, and must be quite energetically costly to produce -- and the skin beneath them tear away with such ease, and can be regenerated quickly and without a scar," says Scherz. The mechanism for regeneration, which is not well understood, could potentially have applications in human medicine, where regeneration research is already being informed by studies on salamander limbs and lizard tails.

Citation
Mark D. Scherz, Juan D. Daza, Jörn Köhler, Miguel Vences, Frank Glaw. 2017.  Off the scale: a new species of fish-scale gecko (Squamata: Gekkonidae: Geckolepis) with exceptionally large scales. PeerJ, 2017; 5: e2955 DOI: 10.7717/peerj.2955

Monday, February 6, 2017

Arthroleptis troglodytes rediscovered in Zimbabwe

In this Dec. 3, 2016 photo, a man holds a rare frog that 
hasn't been seen in decades, in Bulawayo, Zimbabwe. 
 Arthroleptis troglodytes, also known as the “cave 
squeaker” because of its preferred habitat, was 
discovered in 1962 but there were no reported sightings 
of the elusive amphibian after that. An international 
“red list” of threatened species tagged them as 
critically endangered and possibly extinct. 
(AP Photo/ Francois Becker)
The Arthroleptis troglodytes, below, also known as the cave squeaker because of its preferred habitat, was discovered in 1962, but there were no reported sightings of the elusive amphibian after that. An international “red list” of threatened species tagged them as critically endangered and possibly extinct.

Robert Hopkins, a researcher at the Natural History Museum of Zimbabwe, in Bulawayo, said his team had found four specimens of the frog in its known habitat of Chimanimani, a mountainous area in eastern Zimbabwe.

The research team found the first male specimen on Dec. 3 after they followed an animal call they had not heard before, Mr. Hopkins said. They then discovered two other males and a female. Mr. Hopkins said he been looking for the cave squeaker for eight years.

“I was not with my team when they were found,” he said. “I was at the base. I can no longer climb the mountains as I am 75.”

Researchers plan to breed more frogs with the ones taken from their habitat and then reintroduce them to the mountain summit. The frog is tiny and light brown with dark spots.

Now the authorities fear for the frogs’ security, especially because scientists’ and researchers’ huge interest could result in the frog being captured and illegally exported. Mr. Hopkins said 16 specimens were on display at various museums, including the British Museum.

Caroline Washaya-Moyo, a spokeswoman for the Zimbabwe National Parks and Wildlife Management Authority, said: “We are expecting an influx of scientists looking for it. We will do everything in our power to protect and conserve the frog.”

Arthroleptis troglodytes is listed as Critically Endangered by the IUCN because its extent of occurrence (EOO) is 20 km², it occurs in one threat-defined location and there is ongoing decline in the extent and quality of habitat. It was been tagged as Possibly Extinct as it was last seen in 1962 and recent surveys in 2010 failed to detect this species, although it is acknowledged that it may not have been an optimum time in which to detect the species (e.g. not during rains). Most of the specimens were collected in sinkholes or caves and a few were found in open montane grassland. It presumably breeds by direct development. There is very little direct information available for this poorly known species and threats to the species are not well understood. During a survey in 2010, the vicinity of the type locality was found to be intact. However, there are both diamond and gold mining activities locally. The diamond mine at Chimanimani is currently outside the national park, but artisanal mining is known to have caused significant riparian damage on the Zimbabwe side (supposedly worse in the southern part of the park) and is also known to take place in fluvial areas on the Mozambique side. Furthermore, rumours were circulating during a visit in 2010 that the government was considering deproclaiming part of the national park for a commercial gold mine . Thus, considering the available data, it is not implausible that mining activities pose a threat to the species. Finally, as with other species occurring in isolated montane habitats, it could be at risk from the effects of climate change.


Sunday, January 29, 2017

Oldest, most complete iguanian in the Americas

The lizard Magnuviator ovimonsensis is a newly discovered species at Egg
 Mountain in Montana,  US, at a site rich in fossils from the Cretaceous Period. 
The lizard is thought to have lived 75 million years ago. Artist credit: 
Misaki Ouchida
Paleontologists picking through a bounty of fossils from Montana have discovered something unexpected -- a new species of lizard from the late dinosaur era, whose closest relatives roamed in faraway Asia.

This ancient lizard, which lived 75 million years ago in a dinosaur nesting site, is described from stem to stern in a paper published Jan. 25 in the Proceedings of the Royal Society B. Christened Magnuviator ovimonsensis, the new species fills in significant gaps in our understanding of how lizards evolved and spread during the dinosaur era, according to paleontologists at the University of Washington and the Burke Museum of Natural History & Culture who led the study.

"It is incredibly rare to find one complete fossil skeleton from a relatively small creature like this lizard," said David DeMar, lead author and postdoctoral research associate in the UW biology department and the Burke Museum. "But, in fact, we had two specimens, both from the same site at Egg Mountain in Montana."

Right out of the gate, Magnuviator is reshaping how scientists view lizards, their biodiversity and their role in complex ecosystems during this reptile's carefree days in the Cretaceous Period 75 million years ago.

Based on analyses of the nearly complete fossil skeletons, Magnuviator was an ancient offshoot of iguanian lizards -- and they're actually the oldest, most complete iguanian fossils from the Americas. Today, iguanians include chameleons of the Old World, iguanas and anoles in the American tropics and even the infamous water-walking basilisk -- or "Jesus Christ" -- lizards. But based on its anatomy, Magnuviator was at best a distant relative of these modern lizard families, most of which did not arise until after the non-avian dinosaurs -- and quite a few lizards and other creatures -- went extinct 66 million years ago.

The team came to these conclusions after meticulous study of both Egg Mountain specimens over four years. This included a round of CT scans at Seattle Children's Hospital to narrow down the fossil's location within a larger section of rock and a second round at the American Museum of Natural History to digitally reconstruct the skull anatomy. The fact that both skeletons were nearly complete allowed them to determine not only that Magnuviator represented an entirely new species, but also that its closest kin weren't other fossil lizards from the Americas. Instead, it showed striking similarities to other Cretaceous Period iguanians from Mongolia.

"These ancient lineages are not the iguanian lizards which dominate parts of the Americas today, such as anoles and horned lizards," said DeMar. "So discoveries like Magnuviator give us a rare glimpse into the types of 'stem' lizards that were present before the extinction of the dinosaurs."

But Magnuviator's surprises don't end with the Mongolian connection. The site of its discovery is also eye-popping.

Egg Mountain is already famous among fossil hunters. Over 30 years ago, paleontologists discovered the first fossil remains of dinosaur babies there, and it is also one of the first sites in North America where dinosaur eggs were discovered.

"We now recognize Egg Mountain as a unique site for understanding Cretaceous Period ecosystems in North America," said senior author Greg Wilson, UW associate professor of biology and curator of paleontology at the Burke Museum. "We believe both carnivorous and herbivorous dinosaurs came to this site repeatedly to nest, and in the process of excavating this site we are learning more and more about other creatures who lived and died there."

The team even named their new find as homage to its famous home and its close lizard relatives in Asia. Magnuviator ovimonsensis means "mighty traveler from Egg Mountain."

Through excavations at Egg Mountain led by co-author David Varricchio at Montana State University and meticulous analysis of fossils at partner institutions like the UW and the Burke Museum, scientists are piecing together the Egg Mountain ecosystem of 75 million years ago. In those days, Egg Mountain was a semi-arid environment, with little or no water at the surface. Dinosaurs like the duck-billed hadrosaurs and the birdlike, carnivorous Troodon nested there.

Researchers have also unearthed fossilized mammals at Egg Mountain, which are being studied by Wilson's group, as well as wasp pupae cases and pollen grains from plants adapted for dry environments. Based on the structure of Magnuviator's teeth, as well as the eating habits of some lizards today, the researchers believe that it could have feasted on wasps at the Egg Mountain site. Though based on its relatively large size for a lizard -- about 14 inches in length -- Magnuviator could have also eaten something entirely different.

"Due to the significant metabolic requirements to digest plant material, only lizards above a certain body size can eat plants, and Magnuviator definitely falls within that size range," said DeMar.

Whatever its diet, Magnuviator and its relatives in Mongolia did not make it into the modern era. DeMar and co-authors hypothesize that these stem lineages of lizards may have gone extinct along with the non-avian dinosaurs. But given the spotty record for lizards in the fossil record, it will take more Magnuviator-level discoveries to resolve this debate. And, unfortunately, part of the excitement surrounding Magnuviator is that it is a rare find.

Citation
David G. DeMar, Jack L. Conrad, Jason J. Head, David J. Varricchio, Gregory P. Wilson. A new Late Cretaceous iguanomorph from North America and the origin of New World Pleurodonta (Squamata, Iguania). Proceedings of the Royal Society B: Biological Sciences, 2017; 284 (1847): 20161902 DOI: 10.1098/rspb.2016.1902

Sunday, January 15, 2017

The hormonal basis for parental care in rattlesnakes

Pigmy Rattlesnakes, Sistrurus miliarius.
Rattlesnakes have been documented to show parental care, a complex social behavior that is widespread among vertebrates. This behavior has been linked to neuroendocrine regulation in mammals, and, to a lesser extent, birds and fish. However, its influence on reptiles is poorly known. In mammalian species and humans, the posterior pituitary hormones in the  oxytocin and vasopressin families mediate parental care behaviors. In a forthcoming paper in Biology Open, Lind et al. (2017) test the hypothesis that the regulatory role of posterior pituitary neuropeptides is conserved in a viviparous squamate reptile. The researchers pharmacologically blocked the vasotocin receptor in postparturient Pigmy Rattlesnakes, Sistrurus miliarius, and monitored the spatial relationship between females and their offspring relative to controls. Mothers in the control group demonstrated spatial aggregation with offspring, with mothers having greater postparturient energy stores aggregating more closely with their offspring. Blockade of vasotocin receptors eliminated evidence of spatial aggregation between mothers and offspring and eliminated the relationship between maternal energetic status and spatial aggregation. The results are the first to implicate posterior pituitary neuropeptides in the regulation of maternal behavior in a squamate reptile and are consistent with the hypothesis that the neuroendocrine mechanisms underlying social behaviors are broadly conserved among vertebrates.

Citation
Lind CM, Birky NK, Porth AM, Farrell TM. Vasotocin receptor blockade disrupts maternal care of offspring in a viviparous snake, Sistrurus miliarius. Biology Open. 2017 Jan 1:bio-022616.