A new paper appearing in Proceedings of the Royal Society B shows a varied collection of lizards throughout Asia to be unexpectedly close cousins of beach-dwelling mourning geckos, all descended from a common ancestor species that thrived along an ancient archipelago in the West Pacific that served as a “superhighway” of biodiversity.
The dispersal of these lizards, of the genus Lepidodactylus, touches upon a major theory of island biogeography developed by celebrated biologist E.O. Wilson, dubbed the “taxon cycle” model. The new paper also sheds light on lineage diversity and habitat use in the world’s most geologically complex insular region — Pacific island arcs spanning from the Philippines to Fiji.
“One of the things that I find exciting about this work is how our phylogeny, estimated from DNA sequence data, provides evidence for a giant, widespread radiation of variably sized mourning geckos, scaly-toed geckos and their relatives,” said co-author Rafe Brown, professor of ecology & evolutionary biology and senior curator at the KU Biodiversity Institute. “It was a big surprise to find groups of large-bodied, morphologically diverse, deep forest specialists, nested within a widespread clade of small-bodied coastal generalists — we didn’t think they were related at all.”
Brown said some of the mourning geckos’ closest relatives are physically very different, but all “conspicuously” live along island arcs or lost island arcs that have merged into continents, including the modern-day Philippines, northern and eastern New Guinea, eastern Melanesia, Vanuatu, Fiji, Christmas Island and Borneo.
Of 12 major Lepidodactylus lineages, interesting groups include a genus of obligate forest “slender gecko” species and two groups of mysterious “flap-legged” geckos endemic to the Philippines.
“The slender, long-bodied geckos of the genus Pseudogekko live deep in forests, and we didn’t think they were related to the small, primarily coastal scaly-toed geckos,” Brown said. “Another is Luperosaurus, the flap-legged geckos. They’re big and robust and have thorns and flaps all over their bodies, and some are orders of magnitude larger than mourning geckos. It’s astounding that these lizards that are so physically different have turned out to be close relatives.”
Brown’s collaborators included lead author Paul Oliver of Australian National University as well as Fred Kraus of the University of Michigan, Eric Rittmeyer of Rutgers University, Scott Travers of KU and Cameron Siler of the University of Oklahoma.
“To me, this work underscores how much we have yet to understand about the complexity of species diversification on our planet, particularly in island systems,” said Siler. “It is amazing to think about the role these ancient island systems played in the evolution of endemic communities in Wallacea, the West Pacific and Australasia.”
According to Brown, the findings were the result of extensive fieldwork among researchers as well as genetic analysis and data gleaned from biodiversity collections.
“No one research group could ever have put this together alone,” he said. “Firstly, we never knew these groups were closest relatives, and with separate research groups focusing on different regions with what we thought were unrelated lizard faunas, we might not have even put their DNA sequences into analyses together. The sheer magnitude of the sampling around New Guinea, Australasia, Borneo, Melanesia, Christmas Island, the Philippines and across the Pacific made this study possible. The key was putting together the efforts of many friends and colleagues who provided access to their samples and allowed us to paint the whole picture. Some of these lizards are super rare — there’s no way, in a single person’s career, could an individual go to all these places and collect all the necessary samples.”
Brown said the evolution of Lepidodactylus may be tied to the Vitiaz Arc, a near continuous chain of island arcs that stretched across the West Pacific some 30-40 million years ago during the Oligocene, which today is incorporated into present-day landforms ranging from the Philippines to Fiji.
“We used DNA sequencing data and sophisticated statistical analysis to estimate divergence of major groups in the phylogeny,” he said. “Those initial divergences probably date back to between 30 and 40 million years. When you scroll back into Earth’s history, the landmasses looked very different. One thing that jumps out is the inferred existence of a long chain of islands that stretched out across the Pacific called the Vitiaz Arc. This configuration of fragments of modern-day landmasses and islands that have since shifted but once lined up like a kind of superhighway for biodiversity across the Pacific. Given the timing, it seems like that big long chain of islands may have played a role in the evolution of this group.”
Brown said as the Vitiaz Arc fragmented and parts turned into the Philippines, Solomons, Fiji, Vanuatu and other islands that today are all very far apart, they may have facilitated the broad distribution of Lepidodactylus.
“If ancient lineages evolved and gained widespread distribution across this ancient arc, some really may have persisted for the past 30 to 40 million years,” he said.
The dispersal of the Lepidodactylus touches upon the model of the “taxon cycle” proposed by E.O. Wilson in his study of ants in Fiji and New Guinea. Wilson’s idea was that colonizer species are specialized to survive harsh island coastal terrains but eventually evolve traits to adapt to habitats away from island margins — more inland and upland — where some successor species thrive and others go extinct. In the meantime, the original costal colonizers often are replaced by successive waves of new invaders.
“It’s a very famous, influential idea about how species may colonize new islands and habitats and possibly evolve through predictable ecological transitions,” Brown said. “The idea is very provocative because we commonly think about evolution as determined in part by chance, but what some components of species geographical range evolution were almost deterministic? The brilliance of E.O. Wilson was his ability to conceive of a cyclic process based solely on patterns he saw in ant species’ distributions. He didn’t have the phylogenies we have today, but he inferred relations and put this together as a very clear model, with predictions that we can test today with DNA, sophisticated statistics and knowledge of species’ distributions.”
According to Brown, findings in the new paper include support for the taxon cycle model in Lepidodactylus but also some evidence that runs counter to it.
“In some cases, lizard lineages limited to continental fragments have persisted,” he said. “And in some cases, we did not find the most ancient lizards to be specialists from interior habitats on the oldest land masses. Some ancient lineages are found today on the margins of arc islands or just on the edges of larger landmasses. There are exceptions to any rule, of course. For instance, Lepidodactylus ranauensisis — a species that looks like the kind of common lizard that you might expect to find on a coconut tree on a beach in the Philippines—is actually endemic to Mount Kinabalu on Borneo, maybe 32 million years old, and has no close relatives. Perhaps it is the only surviving member of a once more diverse group of lineages that have gone extinct. We just don’t know. But to find these single evolutionary relics is sort of exciting for a phylogeneticist.”
-- by Brendan Lynch, KU News
Photo: Luperosaurus cumingii is one species of unexpectedly related lizards inhabiting Asia. Credit: R.M. Brown
LAWRENCE — Evolutionary biologists long have supposed that when species colonize new geographic regions they often develop new traits and adaptations to deal with their fresh surroundings. They branch from their ancestors and multiply in numbers of species.
Apparently, this isn’t the story of “true frogs.” The frog family scientists call Ranidae are found nearly everywhere in the world, and their family includes familiar amphibians like the American Bullfrog and the European common frog.
New research from the University of Kansas appearing in Royal Society Biology Letters shows, in contrast to expectations, “the rapid global range expansion of true frogs was not associated with increased net-diversification.”
“First, we had to identify where these true frogs came from and when they started their dispersal all over the world,” said lead author Chan Kin Onn, a doctoral student at KU’s Biodiversity Institute. “We found a distinct pattern. The origin of these frogs was Indochina — on the map today, it’s most of mainland Asia, including Thailand, Vietnam, Cambodia and Burma. True frogs dispersed throughout every continent except Antarctica from there. That’s not a new idea. But we found that a lot of this dispersal happened during a short period of time — it was during the late Eocene, about 40 million years ago. That hadn’t really been identified, until now.”
Next, Chan and co-author Rafe Brown, curator-in-charge of the KU Biodiversity Institute’s Herpetology Division, looked to see if this rapid dispersal of true frogs worldwide triggered a matching eruption of speciation.
“That was our expectation,” Chan said. “We thought they’d take off into all this new habitat and resources, with no competition — and boom, you’d have a lot of new species. But we found the exact opposite was true. In most of the groups, nothing happened. There was no increase in speciation. In one of the groups, diversification significantly slowed down. That was the reverse of what was expected.”
To establish the actual timing of true frogs’ diversification, Chan and Brown performed phylogenetic analysis of 402 genetic samples obtained from an online database called GenBank. These samples represented 292 of the known 380 true frog species in the world.
“We mined all of these sequences and combined them into a giant analysis of the whole family,” Chain said. “It is to my knowledge the most comprehensive Ranidae phylogenetic analysis ever performed that included most of the representative species from the family.”
Chan and Brown focused on four genes that would help to establish the family tree of true frogs.
“It’s a genealogical pedigree of specimens, a family tree of species,” Chan said. “Normally, you think of family tree as everyone in one family and how the various people are related. But this is more expanded where we look at how species are related to each other, so you can trace ancestry back in time.”
After completing the phylogenetic analysis, the KU researchers used several frog fossils to “time calibrate” the history of the frogs’ global dispersal.
“We use fossil frogs because we can accurately date the fossils,” Chan said. “We know we found the fossil in a certain rock deposit, and we know with confidence how old the deposit is, so then we can estimate the age of the fossil.”
After Chan and Brown deduced similarities between fossilized true frogs as reported by paleontologists and contemporary true frogs, they placed fossils into groups of closely related species, which scientists call genera.
“Using data from paleontological studies, we can loosely place a fossil where in the phylogeny it belongs and can put a time stamp on that point,” Chan said. “That’s where calibration happens, each fossil is sort of like an anchor point. You can imagine with a really big phylogeny, the more anchor points or calibration points the better your time estimate.”
Through this process, the KU researchers concluded true frogs didn’t become one of the most biodiverse frog families due to dispersing into new ranges, or due to filling a gap created by a catastrophic die-off (such as the Eocene-Oligocene Extinction Event that triggered widespread extinctions from marine invertebrates to mammals in Asia and Europe).
Rather, the rich diversity of species in the Ranidae family comes from millions of years’ worth of continual evolution influenced by a host of different environs.
“Our conclusion is kind of anticlimactic, but it’s cool because it goes against expectations,” Chan said. “We show the reason for species richness was just a really steady accumulation of species through time — there wasn’t a big event that caused this family to diversify like crazy.”
- Brendan M. Lynch, KU News
Top image: KU researchers concluded true frogs didn’t become one of the most biodiverse frog family due to dispersing into new ranges, or due to filling a gap created by a catastrophic die-off. Rather, the rich diversity of species in the Ranidae family comes from millions of years’ worth of continual evolution influenced by a host of different environs. Image by R.M. Brown.
From top right: The Rana igorota; Sangirana tipanan; Spotted stream (an Asian true frog); another Asian true frog. Photos courtesy of Chan Kin Onn, a doctoral student at KU’s Biodiversity Institute.
The interplay between range expansion and concomitant diversification is of fundamental interest to evolutionary biologists, particularly when linked to intercontinental dispersal and/or large scale extinctions. The evolutionary history of true frogs has been characterized by circumglobal range expansion. As a lineage that survived the Eocene–Oligocene extinction event (EOEE), the group provides an ideal system to test the prediction that range expansion triggers increased net diversification. We constructed the most densely sampled, time-calibrated phylogeny to date in order to: (i) characterize tempo and patterns of diversification; (ii) assess the impact of the EOEE; and (iii) test the hypothesis that range expansion was followed by increased net diversification. We show that late Eocene colonization of novel biogeographic regions was not affected by the EOEE and surprisingly, global expansion was not followed by increased net diversification. On the contrary, the diversification rate declined or did not shift following geographical expansion. Thus, the diversification history of true frogs contradicts the prevailing expectation that amphibian net diversification accelerated towards the present or increased following range expansion. Rather, our results demonstrate that despite their dynamic biogeographic history, true frogs diversified at a relatively constantly rate, even as they colonized the major land masses of Earth.
Check out the study titled “Did true frogs ‘dispersify’?” here.
LAWRENCE — Growing up around Havana, Javier Torres López always was fascinated by reptiles. As the son of a professor who teaches vertebrate zoology at the University of Havana, he focused on studies of literature and science in high school and thought about following in his father’s footsteps.
“In Cuba, everyone has an opportunity to go to university,” he said. “You have to take tests according to your preferred major, and you have the right to pick up to 10 majors. Based on the tests results and your high school score, you get one of the 10 options. I was able to obtain my first choice, biology. So, I started studying at the University of Havana as a biology major — that was in 2004. There, for the first time, I started to become aware of the diversity of Cuban and Caribbean amphibians and reptiles.”
As an undergraduate, Torres started conducting original research, finding himself drawn to Tropidophis, a genus of dwarf boa snakes endemic to the Caribbean and South America.
“I was totally into studying snakes,” Torres said. “I found out about this particular group of Cuban snakes called dwarf boas. Studying the behavior of those snakes got me a ticket to the Latin American Herpetology Congress held in Cuba in 2008.”
There, Torres had his first contact with Rich Glor, KU associate professor of ecology & evolutionary biology and associate curator at KU’s Biodiversity Institute. The two stayed in contact over the years as Torres completed his undergraduate studies. All the while, Torres continued to investigate species endemic to Cuba, spending time in the field and learning important lessons about research.
“After a while studying the behavior and biology of dwarf boas, I understood it was a difficult system to work with because they are quite rare and hard to find,” Torres said. “So, I started to work on a project to understand the distribution of diversity depending on the landscape. On this project, I started to study anoles, a group of diurnal lizards highly diversified in Cuba. It’s the richest island when we talk about anoles. In contrast to dwarf boas, they’re quite common, and you can find enough individuals to let you answer questions in ecology, evolution and conservation.”
Researching Cuban anoles, Torres earned his master’s degree by studying the consequences of hybridization among different anole species. He also spent several years teaching zoology and herpetology as an instructor at the University of Havana. While he contemplated earning a doctorate, he kept in touch with Glor at KU.
“While working on my master’s, I was reading Rich’s papers, and I really liked that our interests were alike,” Torres said. “So, I wrote to him and we started to exchange information. I came to the U.S., and he came to Cuba. Finally, I applied here and I am following Ph.D. studies in the same vein as my master’s, with a side project on Tropidophis.”
Now at KU, Torres holds his Cuban citizenship and makes return visits to his home island.
He maintains strong ties with his professional colleagues in Cuba, where he continues to advise students at the University of Havana. He also recently submitted a grant to National Geographic to fund several major field expeditions back to Cuba.
Indeed, Torres is already making vital contributions to herpetological research at KU. He has donated a major collection of tissue samples of reptile species endemic to Cuba to KU’s Biodiversity Institute. The valuable material can be used by current and future researchers interested in Cuban and Caribbean herpetology.
“When I traveled here to start my Ph.D., I brought 400 tissue samples of Cuban reptiles, and last month I went home to Cuba and brought back about 600 more samples — now the Biodiversity Institute has about 1,000 samples of 63 Cuban species, mostly reptiles, and most of them are endemic,” Torres said. “I would say the KU Biodiversity Institute harbors one of the most important tissue collections of Cuban reptiles. A tissue sample is the raw material for conducting genetic studies. There is a lot of things you can do with genetics, but there is a major concern in evolutionary biology which genetics allows us to understand better — how and why new species arise. From that number of samples, you can think of several projects involving the study of the DNA.”
Moreover, Torres and Glor traveled this summer to Cuba, where they worked on preparation of 760 whole specimens for eventual transport to KU. “The plan is to bring those back the next time I travel to Cuba,” Torres said.
“This will be the most important collection of Cuban reptiles brought to the United States in the past 20 years and includes lots of rare Cuban endemics,” Glor said.
Studying in the U.S. has some major advantages over the choices and technologies made available at Cuban universities, according to Torres.
“Here, it is easier to build your preferred curriculum because there are more options of classes — in Cuba, you have more mandatory and less optional classes. But the largest difference is in the area of resources. In Cuba, we have a great theoretical program, but when you have to do labwork, we don’t have all necessary tools and equipment and we have to search for alternatives. So basically, here there’s better availability of textbooks, journals, internet and technology.
“I feel very pleased and very lucky to be here in at the Biodiversity Institute,” he said. “Particularly the herpetology division here at KU is a great group to be with. For me, the first months were tough, but thanks to the help I found in my adviser, fellow students and other researchers at the herpetology division (and the BI in general) I made it through.”
That said, Torres finds himself missing many of the most important aspects of home. Most of all, Torres misses his family and girlfriend. “I don’t have to think about answering that,” he said.
But he also finds himself craving Cuban home cooking.
“I’m planning to go home in December to spend New Year’s Eve in Cuba,” Torres said. “It is a tradition in there to spend it with family eating roast pork, rice, beans, yucca, fried plantain and salad. I love this town, but Cuban cuisine is different from what you find in Lawrence. I don’t think there’s an authentic Cuban restaurant. I had a Cuban sandwich here — it was very good, but it wasn’t Cuban.”
Photos (courtesy of Javier Torres López):
Top left: Relocating a group of giant tropes (Tropidophis melanurus) found in a risky area.
Bottom right: The largest toad in Cuba, Peltophryne fustiger, is quite common in the west.
- Brendan M. Lynch, KU News
The National Science Foundation has awarded support for a team that includes Biodiversity Institute researchers in ornithology and herpetology. The project, “Open Exploration of Vertebrate Diversity in 3D,” or informally, the “scan all vertebrates” project, aims to run 20,000 preserved vertebrate specimens from university and museum collections through computerized tomography, or CT scans, over the next 4 years. Scientists from the 16 participating institutions hope the oVert museum digitization effort will form the backbone of future research in fields such as developmental biology, evolution, and biomimetics. The project will cover about 80% of living vertebrate genera.
KU’s role is mainly to provide specimens from the collections to scanning facilities. Funds awarded to KU for the project will be used to pull specimens from the collections and ship them to facilities with CT scanners. Most of the money will go toward summer support for graduate students who will be completing the required work.
Every March 17, lovers of Irish culture around the world commemorate the life and legend of a fifth-century missionary best known for spreading Christianity in Ireland, but also for driving all of the island’s snakes into the sea.
But could the tale of St. Patrick conceivably explain Ireland’s lack of snakes? Is it even possible to herd snakes? Could these long-banished serpents someday make their way back to Ireland?
Between lashings of green beer and plates heaped with corned beef and cabbage, such questions gnaw at every Hibernophile.
The University of Kansas’ Biodiversity Institute has one of the world’s foremost assemblage of herpetologists — and that's not blarney. These researchers, like St. Patrick himself, show a legendary penchant for chasing snakes. In honor of St. Patrick’s Day, a group of scientists in the Division of Herpetology flashed their gift for the gab in pondering both the science and myth behind the Patron Saint of Ireland.
Q: Legend holds that St. Patrick drove all the snakes from Ireland in the fifth century. Would it be possible for one man to drive snakes from an entire island nation? How might one man go about it?
Rich Glor, curator of herpetology: I’m not going to fact-check the legend — after all, the guy was a saint, and who am I to question his accomplishments? Normal humans have had a very difficult time eliminating some island snake populations. The brown tree snake, for example, was accidentally introduced to the island of Guam, which previously had no snakes. Guam’s birds, some of which were found nowhere else in the world, were poorly prepared for this new predator, and many have been driven to extinction or near extinction as a result.
Concentrated efforts to exterminate the tree snakes have included electrified snake containment fences and teams of hunters using trained snake-sniffing dogs, but it seems like the snakes are there to stay. On the other hand, however, humans have done a very good job of driving snakes to the brink of extinction. In the United States, for example, humans have undertaken a more than century-long effort to exterminate rattlesnakes. This effort, which continues to this day in some parts of the country, has resulted in the extinction of rattlesnakes across much of their ancestral range and has led to the classification of many rattlesnake populations as endangered.
Historical records suggest that individual snake hunters were often responsible for wiping out entire populations by capturing and killing all of the individuals as they emerged from communal hibernation dens in the spring. St. Patrick’s task would certainly have been easier if Ireland’s legendary snakes used the same type of communal hibernation strategy as rattlesnakes. Other rattlesnake hunters use even more nefarious strategies: Snake hunters at rattlesnake roundups, for example, often spray gasoline into snake dens and catch the snakes as they exit the den attempting to flee the noxious fumes, but a man of the cloth seems very unlikely to have adopted such a grotesque approach.
Luke Welton, the Herpetology Division’s collections manager: It’s quite interesting that no native snakes are currently known from Ireland, despite a number of species occurring in more southerly parts of the United Kingdom. One consideration is that the climate of Ireland would likely keep any potential populations of ectotherms fairly small, which would make them much more susceptible to extinction or eradication.
Q: Supposedly, St. Patrick drove the snakes into the sea. Can a person drive snakes in a given direction, and would they perish if you drove them into an ocean?
Jeff Weinell, graduate student: During fieldwork, herpetologists often use drift fences (sheet metal or mesh partially buried along one edge) to direct snakes and other small reptiles toward a particular direction (usually into a bucket). However, this method wouldn't work to direct most snakes into the ocean, and, therefore, St. Patrick probably didn't use drift fences. Some snakes do live in the ocean, but these species are only found in the Pacific and Indian oceans. If St. Patrick found a way to put all of the snakes of Ireland directly into the ocean, most probably would have perished. However, many snakes are good swimmers, and some of them may have been able to find their way back to shore.
Glor: For anybody who’s not a saint, herding snakes might be even more difficult than herding cats. Herpetologists sometimes use low fences to corral snakes, but even this is only partly effective. Most snakes would perish if forced into the ocean. Ocean-dwelling snakes, which are not found anywhere near Ireland, have numerous specializations that permit them to live in the ocean that other snakes lack. For example, ocean snakes have special physiological mechanisms to cope with saltwater. They also have flattened oar-like tails and specialized scales that allow them to swim in ocean waters.
Q: If it wasn't St. Patrick’s doing, what are the scientific reasons for the lack of snakes in Ireland? Are there other places without snakes? Why?
Katie Allen, graduate student: The scientific reason there are no snakes in Ireland is actually a result of the last Ice Age. As recently as about 19,000 years ago Ireland was buried in 3,000 meters (9,800 feet) of ice and was essentially an arctic wasteland. After the glaciers melted, the Irish Sea formed and created a 50-mile-wide barrier between the island and the mainland. During the Ice Age, snakes were not able to survive in Ireland, and afterward they were not able to cross the large, cold sea to reach it. There are several other islands that naturally do not have any snakes, including Greenland, Iceland, New Zealand and Hawaii. These islands are snake-free for similar reasons; either climate or distance from the mainland prevents colonization. Iceland, New Zealand and Hawaii have also banned pet snakes in order to keep their islands free of scaly invaders.
Q: Are there any reptiles in Ireland?
Glor: Yes, Ireland has one lizard species, which is called the "common lizard" but is actually unusual among lizards because it gives birth to live young rather than laying eggs.
Allen: Only one species of lizard is native to Ireland, the viviparous lizard (Zootoca vivipara). This species is widely distributed across Europe and Asia and is able to live farther north than any other terrestrial reptile. One of its adaptations to this cold lifestyle is to give birth to live young instead of laying eggs. Aside from this lizard, there are several species of sea turtles that inhabit the coastal areas of Ireland.
Q: What would be the most effective way to drive snakes from your yard, garden or house?
Glor: Why would you want to drive snakes from your yard, garden or house?
Brown: That’s the last thing I would do. The real question is, “How can we attract more snakes to our yards, gardens, and yes, even basements of our houses?” If we had more snakes around, we wouldn’t have to buy traps and poisons to handle household pests like rats and mice.
Q: What are the benefit of snakes to an ecosystem like the one in Ireland? Are snakes a benefit to humans in ways that are underappreciated? What are the drawbacks of snakes?
Glor: Nobody knows what effect snakes could have on an ecosystem like Ireland’s. In some ecosystems, snakes are major predators of small animals like mice. I don’t think snakes are a benefit to humans in ways that are underappreciated. Most snakes have no drawbacks outside of causing irrational fear in some humans. Some snakes are venomous and can be dangerous to humans.
Brown: In all seriousness, and particularly with regard to human health issues, snakes are highly beneficial. For example, scientists have documented that the primary reservoir for the explosive spread of Lyme disease in this part of the country are ticks, which are transported by mammals like deer and rodents. Additionally, most people contract Lyme disease doing regular household things like gardening or raking leaves in their own yard because they come in contact with ticks carried by rodents. I would much rather have a healthy population of harmless black rat snakes in my yard than an infestation of filthy, debilitating disease-carrying rodents. But, you know, that’s just me.
Welton: Snakes are quite beneficial ecologically. They are the controllers of rodent and pest populations and are exactly the kinds of predators that keep vectors of some human diseases at bay. No snakes would likely mean an increase in diseases like hantavirus and plague, which are carried by rodents. Besides just the disease aspect, would you rather have one snake in your garage or basement, or several hundred mice or rats?
Q: Why do people dislike snakes? Why does our culture associate snakes with evil?
Glor: Many people have done research on this topic without firm answers. Some people believe a fear of snakes is hardwired due to our ancestors’ interactions with deadly venomous snakes. One need look no further than the first chapter of the Good Book to get a sense for why our western culture associates snakes with evil; after the snake deceives Eve in the Garden of Eden, God curses snakes over all other animals and tells the snake “on your belly you will go, and dust you will eat all the days of your life” (which makes one wonder how snakes were getting around prior to the curse).
Brown: Sometimes I think people don’t like snakes because of the way they move. People just get creeped out by “slithering” snakes and almost instinctively recoil when they first see a snake. Unfortunately, humans also react violently when they see a snake move — by what scientists term “lateral undulation” (slithering). However, scientists infer from the existence of many well-preserved transitional fossils of intermediate forms that snakes evolved from ancestors that possessed limbs. Not only does the fossil record tell how the ancestors of today’s snakes lost limbs and evolved elongated body plans over evolutionary timescales, but in today’s “primitive” living snakes, the vestiges of those limbs can be seen — in pythons, for example, that still have tiny claws at the base of their tails. So we can actually view snakes as just one group of very specialized, highly successful lizards. Strangely, in this instance, the biblical account and evolutionary biology’s explanation are curiously aligned. And yet no one ever tries to exterminate lizards on their property or dig up lizard dens with the goal of mass-murdering all inhabitants.
Welton: In my opinion, society is largely the reason most people fear snakes. I don't know that there is a single group of animals that has had so much misinformation disseminated about it. One could argue that this fear stems from the Garden of Eden story and that all snakes are inherently bad. While I believe that definitely plays a part, I think the fear is a symptom of a larger problem associated with a lack of education. Too often, completely harmless (nonvenomous) snakes meet their end because of common defensive strategies (striking with mouth agape, rattling their rattle-less tails in debris or leaf-litter) that are intended to fool a would-be predator. This needless slaughter could almost always be prevented if one cared enough to become educated about the wildlife in their own backyard.
Q: Might snakes return to Ireland, due to changing climate or pet snakes being released into the wild? What would be the most likely species to thrive in Ireland?
Glor: Yes, this is definitely a possibility. Snakes found in nearby England are the most likely colonists.
Q: What are the main threats to snake biodiversity today globally?
Glor: Habitat loss is the greatest threat to biodiversity. In cases, specific populations are overexploited by pet trade.
Brown: And overall persecution by humans. Globally, when snake populations come in contact with human populations, the outcome usually is unfortunate and does not bode well for the long-term viability of the snake population. I agree with Luke, though — education is the key ensuring the conservation and long-term survival of the world’s 3,650 species of snakes.
-By Brendan Lynch
Photo: Snakes from the KU Biodiversity Institute herpetology collections
William Duellman, curator emeritus, has been featured in National Geographic news for his herpetology research. Liz Langley referenced Duellman’s book Marsupial Frogs in her article, “5 Animals That Carry Babies On Their Backs,” noting the unique ways some frogs from the South and Central American regions lay their eggs. As explained in Duellman’s book, some frogs, such as the horned marsupial frog, lay their eggs in a pouch located under the skin on the mother’s back as the tissue of the pouch allows for vital nutrients to get through to the eggs. Read more here.
Photo by Joel Sartore
The Solomon Islands in the Southwest Pacific are best known as a locale for some of the most intense fighting of the Second World War, including the bloody Battle of Guadalcanal. But for nearly a century, the rich biodiversity of the islands has been instrumental to the study of evolution, including research by noted scientists Ernst Mayr and Jared Diamond.
“Leading ideas of how speciation happens and evolution occurs were formed based on birds and frogs in this region,” said Rob Moyle, associate curator at the University of Kansas’ Biodiversity Institute, who specializes in the evolution of birds. “The islands are incredibly beautiful places but also at times incredibly inhospitable, very hot with really rough terrain and torrential downpours.”
Today, Moyle is leading a major research effort in the region supported by $1.3 million from the National Science Foundation to conduct fieldwork, collect museum specimens, record bioacoustics and sequence DNA of birds, reptiles, amphibians and mammals.
“We want to go back to test hypotheses, fill in gaps in the data and revisit this with much more modern methods than they were using decades ago,” Moyle said. “Some of the problems doing this work today are permitting issues and national boundaries. In the past, researchers just went island to island and collected what they wanted. It’s difficult to do the same thing today, but that’s what we’re hoping to do.”
The grant includes fieldwork spread across three nations — the Solomon Islands, New Guinea and Vanuatu. Many islands in the region are remote and isolated, making travel difficult for the researchers hoping to follow up on work performed by earlier biologists.
“Getting there isn’t simple,” Moyle said. “From the U.S., you have to go through Australia and fly back several hours to get to the Solomons. Very few airlines go there, but the main islands have little airstrips you get to on a little Twin Otter prop plane. To get to most small islands, you take small outboard boats. That can be iffy, because you go across some pretty open ocean crossings. Then, sometimes we take a boat up the river — a year ago we took a helicopter to a site in Guadalcanal.”
Moyle’s colleagues include KU’s Rafe Brown, who is in charge of amphibian and reptile work; Chris Filardi, senior scientist at Conservation International; Michael Andersen of the University of New Mexico; Tyrone Lavery of the University of Queensland, Australia; Jonathan Richmond of the U.S. Geological Survey; and many participants and collaborators in the Solomon Islands, including David Boseto, co-director of Ecological Solutions Solomon Islands, a group dedicated to environmental research and conservation.
In the field, biologists will camp in teams ranging from two to 20 people, performing their work in shifts that depend on the animals of interest.
“If you’re studying birds, you’re up early,” Moyle said. “Our day starts before dawn, getting up, getting ready, getting tape recorders ready for vocalizations, getting nets ready — that goes through mid-morning, then we have work back at camp to preserve and prepare specimens. If you study frogs, you go herping at night. Sometimes we overlap, the herpetologists get back late, and the bird people are getting up.”
The teams will include many graduate and undergraduate students from KU and partner institutions.
“Graduate students will be heavily involved in fieldwork, lab work and publishing papers,” Moyle said. “We’ll also bring undergrads from the U.S. over to the Solomon Islands. They’ll be paired with undergraduates from the Solomons to work on research projects — so there’s both an international cultural experience as well as a scientific project.”
Back at KU’s specialized labs, researchers will conduct genomic sequencing of samples from the field to establish relationships between species and determine when separate species may have branched off from each other.
“Traditionally, scientists would collect bird specimens and their insights into what went on in a region came from looking at plumage color, the size and shape of the animal, and looking at maps of where they occurred on islands, but physical appearance can be very misleading,” Moyle said. “Genomic sequencing opened up new realm of inquiry, not just for figuring out if specimens A and B are related, or if A is more closely related to C, but also figuring out how quickly they diversified or how long ago they arrived in the archipelago.”
Moyle and his colleagues will use a process called “high-throughput sequencing” to trace how gene flow occurs between populations separated on isolated islands.
“Sometimes, we see there are populations on different islands that look or sound very different, and, so far, we actually can’t tell them apart genetically,” Moyle said. “We know there are differences in there, but it shows how little change there has to be in the genome to get something that sounds and looks very different. With some of this work, we’re able to identify the specific genes for differences we’re seeing among the species.”
Moreover, the scientists are likely to identify species that are unknown to science and describe them for the first time.
In addition to the scientific value of the research, work performed under the grant will inform policymakers and conservationists looking to protect biodiversity in the region.
“These islands are under great threat from a variety of sources,” Moyle said. “The most prominent threat is logging, but there are also some very aggressive resource extractions like gold, nickel, and bauxite mines and oil drilling. Some of these islands aren’t that large, and there’s not much forest left, so figuring out where species are and what’s left of them can give conservationists and governments some data to work with to make informed decisions.” - Brendan Lynch, KU News
Photos, from top:
The Solomon Island Palm Frog (Cornufer heffernani) is uncommon and found only in pristine rainforest. Its chirping call is often heard after heavy rains. Credit: Scott Travers
Mark Robbins, collection manager of birds in the KU Biodiversity Institute, examines bird specimens during a 2014 expedition to Choiseul Island while local guides from the Lauru Land Tribal Community look on. Credit: Scott Travers
The Solomon Island Eyelash Frog (Cornufer guentheri) is widely distributed in the archipelago and is an example of direct development – they skip the tadpole phase and hatch from eggs as tiny but fully developed frogs. Credit: Scott Travers
The field team at Nunubala camp, West Kwaio Region of Malaita Island during a 2015 expedition, including KU graduate students, local guides and Solomon Islands researchers. Credit: Scott Travers
The Collared Kingfisher (Todiramphus chloris) is ubiquitous in the region. Like most Old World kingfishers, this species is not a fisher but instead inhabits forest and open country, feeding on insects and small vertebrates. Credit: Rob Moyle.
Herpetologist Rich Glor was on KCUR to discuss how anoles branch into various species and his research on what defines a species. Listen to the broadcast here.
LAWRENCE — For about 60 million years during the Eocene epoch, the Indian subcontinent was a huge island. Having broken off from the ancient continent of Gondwanaland, the Indian Tectonic Plate drifted toward Eurasia.
During that gradual voyage, the subcontinent saw a blossoming of exceptional wildlife, and when the trove of unique biodiversity finally made contact with bigger Eurasia, the exchange of animals and plants between these areas laid the foundations for countless modern species.
“Today, mainland Asia and India have all this unique biodiversity — but did the mainland Asian biodiversity come from India, or did the Indian biodiversity come from other regions of Asia?” asked Jesse Grismer, doctoral candidate with the Biodiversity Institute at the University of Kansas.
Grismer claims the answer depends on the organism in question.
“If you picked Asian freshwater crabs, you’d see they started in India and made their way to Asia, but if you picked dragon lizards you’d get the opposite answer,” he said. “The opposing distribution patterns created a lot of conflict for a while. You’d see papers saying, ‘Everything came from India,’ and others saying, ‘No, everything came from Indochina and Southeast Asia.’ But they were looking at opposite ends of the same pattern, just with different animals.”
Now, Grismer has authored research appearing in the journal BMC Evolutionary Biology showing that before the final collision of Eurasia and the Indian subcontinent, land bridges between the landmasses may have served as “freeways” of biodiversity exchange that flowed in both directions.
“Our paper shows that as India was approaching Eurasia, it was connecting by ephemeral land bridges,” Grismer said. “It was these land bridges that allowed for dispersal and exchange of all these species. There were two areas of suitable habitat separated by unsuitable oceans. But once that new area was exposed, species were allowed to disperse into mainland Asia or India, respectively, areas that these species had not been able to previously exploit.”
To arrive at their conclusion, Grismer and his co-authors performed a phylogenomic analysis of Indian Dragon Lizards, revealing multiple origins in Southeast Asia. The researchers included Alana Alexander, Phillip Wagner, Scott L. Travers, Matt D. Buehler, Luke J. Welton and Rafe M. Brown from KU and James A. Schulte II from Clarkson University. Grismer also credits his KU lab mates Chan Kin Onn, Robin Abraham and Carl Hutter with help on the research via “a lot of fruitful discussion.”
Importantly, the team showed that two land bridges connected the Indian subcontinent to Eurasia at two different times during the early to middle Eocene, some 35 to 40 million years ago.
“This hypothesis is based on evolutionary relationships between the species used in this study,” he said. Grismer added that his team blended new genomic data with previous studies and combined that analysis with new geologic studies about Eocene geology.
The KU researcher said Indian Dragon Lizards, or the Draconinae subfamily of the lizard family Agamidae, are an ideal species to study in order to piece together a picture of the exchange of biodiversity that took place due to the land bridges.
“Dragon lizards added new light because of the previous work that has been done on them, plus our new samples,” Grismer said. “They’re quite diverse as a group, distributed equally, and so they’re great study system for testing a new hypotheses.”
He added that conservation of certain species of Dragon Lizards and keeping them out of the international pet trade would help make possible more opportunities for understanding the history of this unique group of family of lizards.
“We were only able to do this because we had all these species to work with, and a future study with more data and new species could find a new result to this question ” he said. “Animals in general tell us a lot about our world and how we fit into it. I think protecting them is just as important as anything else we do.”
Top photo: Jesse Grismer, doctoral candidate with the Biodiversity Institute at the University of Kansas, recently published research in the journal BMC Evolutionary Biology. Photo by Meg Kumin, KU Marketing Communications.
Top right image: A map shows the distribution of Draconinae and the four biogeographic area (differently colored borders) used in ancestral range reconstructions. Image courtesy Jesse Grismer.
Bottom right image: b Hypothesized position of the ISC and an early Eocene land bridge allowing for the first inferred dispersal event (D#1 in a) from Eurasia into India, 50–55 MYA. c. Hypothesized position of the ISC and a middle-late Eocene land bridge allowing for the second first inferred dispersal event (D#2 in a) from Eurasia into India between 35–50 MYA (paleomaps modified from Klaus et al.) Image courtesy Jesse Grismer.
-Brendan M. Lynch