Smithsonian Science » Tropical Research Institute

Giant prehistoric turtle from Colombia chomped everything in sight–including crocodiles!

John Barrat — Thu, 17 May 2012 17:39:39 +0000

Picture a turtle the size of a Smart car, with a shell large enough to double as a kiddie pool. Paleontologists from North Carolina State University, the Smithsonian Tropical Research Institute and the Florida Museum of Natural History have just described such a specimen from the fossilized remains of this 60-million-year-old South American giant that lived in what is now Colombia.

Image right: Artist’s conception of Carbonemys eating a small crocodylomorph (Artwork by Liz Bradford)

The turtle in question is Carbonemys cofrinii, which means “coal turtle,” and is part of a group of side-necked turtles known as pelomedusoides. The fossil was named Carbonemys because it was discovered in 2005 in a coal mine that was part of northern Colombia’s Cerrejon formation. The specimen’s skull measures 24 centimeters, roughly the size of a regulation NFL football. The shell which was recovered nearby – and is believed to belong to the same species – measures 172 centimeters, or about 5 feet 7 inches, long. That’s the same height as Edwin Cadena, the NC State doctoral student who discovered the fossil.

Cadena; Dan Ksepka, N.C. State paleontologist and research associate at the North Carolina Museum of Natural Sciences; paleontologist Carlos Jaramillo of the Smithsonian Tropical Research Institute in Panama, and paleontologist Jonathan Bloch of the Florida Museum of Natural History are co-authors of the scientific description of the turtle which appears in the Journal of Systematic Paleontology.

Image left: Edwin Cadena, the scientist who discovered the fossil of Carbonemys, poses next to its reconstructed fossil shell. (Photo courtesy Dan Ksepka, NC State University)

“We had recovered smaller turtle specimens from the site. But after spending about four days working on uncovering the shell, I realized that this particular turtle was the biggest anyone had found in this area for this time period – and it gave us the first evidence of giantism in freshwater turtles,” Cadena says.

Smaller relatives of Carbonemys existed alongside dinosaurs. But the giant version appeared five million years after the dinosaurs vanished, during a period when giant varieties of many different reptiles – including Titanoboa cerrejonensis, the largest snake ever discovered – lived in this part of South America. Researchers believe that a combination of changes in the ecosystem, including fewer predators, a larger habitat area, plentiful food supply and climate changes, worked together to allow these giant species to survive. Carbonemys’ habitat would have resembled a much warmer modern-day Orinoco or Amazon River delta.

In addition to the turtle’s huge size, the fossil also shows that this particular turtle had massive, powerful jaws that would have enabled the omnivore to eat anything nearby – from mollusks to smaller turtles or even crocodiles.

Thus far, only one specimen of this size has been recovered. Palentologist Ksepka believes that this is because a turtle of this size would need a large territory in order to obtain enough food to survive. “It’s like having one big snapping turtle living in the middle of a lake,” he says. “That turtle survives because it has eaten all of the major competitors for resources. We found many bite-marked shells at this site that show crocodilians preyed on side-necked turtles. None would have bothered an adult Carbonemys, though – in fact smaller crocs would have been easy prey for this behemoth.”–Source: NC State University

Heliconius butterfly genome explains wing pattern diversity

John Barrat — Thu, 17 May 2012 01:25:58 +0000

Pooling funds and putting their heads together, more than 70 scientists from 9 institutions including the Smithsonian Tropical Research Institute, sequenced the entire genome of the butterfly genus Heliconius, a brightly colored favorite of collectors and scientists since the Victorian era. Their results are published in the prestigious journal, Nature.

Image right: Based on the new sequence, scientists found that different species copy each other’s wing patterns by exchanging genes, a process thought to be very rare, especially in animals. (Photo by Mathieu Joron)

The genome of the Postman butterfly, Panama’s Heliconius melpomene, helps scientists understand how the stunning diversity of wing color patterns in tropical butterflies evolved. Heliconius species are highly distasteful. Their vivid wing patterns warn predators not to eat them. How have different butterfly species evolved similar wing patterns?

Based on the new sequence, scientists found that different species copy each other’s wing patterns by exchanging genes, a process thought to be very rare, especially in animals. Although many different species interbreed in the wild, their hybrid offspring often cannot reproduce successfully. But sometimes hybrids gain useful genes that help them adapt to changing conditions. Heliconius hybrids gain wing patterns that help them survive.

Kanchon Dasmahapatra, the a lead author of the study and a former Smithsonian fellow who worked with Jim Mallet at University College London notes: “What we discovered is that one butterfly species can gain its protective colour pattern genes ready-made from a different species by hybridizing with it–a much faster process than having to evolve one’s colour patterns from scratch.”

Some of the other genes in the sequence also surprised researchers. These butterflies, typically regarded as primarily visual insects, apparently have a rich array of genes for smelling and sensing chemicals in their environment, raising new questions about the links between perception and the origins of new species. Indeed, analysis carried out at the University of California by co-author Adriana Briscoe showed that butterflies have an even greater array of genes involved in chemical communication than moths, which depend on chemical signals for finding mates and host plants.

The study heralds a new era in genome biology and an important step in the Smithsonian’s goal to understand and sustain a biodiverse planet. Low-cost genetic sequencing opens doors to small research groups and individuals to sequence entire genomes, a technique formerly accessible only to labs with major government funding.

“Assembling a genome from scratch is still hard work: think Humpy-Dumpty,” said Owen McMillan, geneticist and Academic Dean at the Smithsonian Tropical Research Institute, “but it is getting easy, inexpensive, and is transforming how we do science. At the core, having a reference genome opens up new research possibilities and reveals previously unimagined connections.

Heavyweight trees are forest champs at sequestering carbon

John Barrat — Thu, 03 May 2012 16:36:41 +0000

Big trees three or more feet in diameter accounted for nearly half the biomass measured at a Yosemite National Park site, yet represented only one percent of the trees growing there.

This means just a few towering white fir, sugar pine and incense cedars per acre at the Yosemite site are disproportionately responsible for photosynthesis, converting carbon dioxide into plant tissue and sequestering that carbon in the forest, sometimes for centuries, according to James Lutz, a University of Washington research scientist in environmental and forest sciences. Lutz is lead author of a paper on the largest quantitative study yet of the importance of big trees in temperate forests being published online May 2 on PLoS ONE. The research was funded by the Smithsonian Center for Tropical Forest Science.

Image right: A handful of large-diameter trees per acre, such as these incense cedars, together with remains of big trees like the three-foot-wide white fir snag and downed debris account for half the forest biomass at a Yosemite National park study site. (Image by James Lutz)

“In a forest comprised of younger trees that are generally the same age, if you lose one percent of the trees, you lose one percent of the biomass,” he says. “In a forest with large trees like the one we studied, if you lose one percent of the trees, you could lose half the biomass.”

In 2009, scientists including Lutz reported that the density of large-diameter trees declined nearly 25 percent between the 1930s and 1990s in Yosemite National Park, even though the area was never logged. Scientists have found notable numbers of large trees dying in similar areas across the West.

The new 63-acre study site is one of the largest, fully-mapped plots in the world and the largest old-growth plot in North America. The tally of what’s there, including the counting and tagging of 34,500 live trees, was done by citizen scientists. The site is part of the network of the Smithsonian Center for Tropical Forest Science, a global network of 42 tropical and temperate forest plots including the one in Yosemite.

Image left: Washington State University’s Mark Swanson pulls a tape tight around a 4-foot-wide sugar pine, one of the 34,500 live trees counted and tagged for long-term study in a Yosemite National Park study plot. (Washington State University)

One implication of the research is that land managers may want to pay more attention to existing big trees, the co-authors said. In some younger forests that lack big trees, citizens and land managers might want to consider fostering the growth of a few big-trunked trees, Lutz added.–Source: University of Washington.

Global forest science research center moves from Harvard to the National Museum of Natural History, Washington, D.C.

John Barrat — Wed, 02 May 2012 14:32:22 +0000

In May, the Center for Tropical Forest Science-Smithsonian Institution Global Earth Observatory is moving from its headquarters at Harvard University to the Smithsonian’s National Museum of Natural History in Washington, D.C. The move enhances coordination efforts for the 46-plot research network, which partners with more than 75 institutions in 21 countries, including the Smithsonian’s Natural History Museum, the Smithsonian Conservation Biology Institute and the Smithsonian Environmental Research Center.

CTFS-SIGEO is a global network of forest research plots committed to the study of tropical and temperate forest function and diversity. The multi-institutional network includes plots across the Americas, Africa, Asia, and Europe, with a strong focus on tropical regions. Ecologists at the Smithsonian Tropical Research Institute established the first forest dynamics plot on Barro Colorado Island in the Panama Canal in 1980.

Image left: Daniel Johnson, a biology graduate student at Indiana University, measures the diameter of a white ash tree in the University’s Lilly-Dickey Woods. The 550-acre woods were recently added to CTFS-SIGEO’s global network of forest research plots. (Photo by F. Collin Hobbs)

Stuart J. Davies, CTFS-SIGEO director and senior staff scientist at the Smithsonian Tropical Research Institute, will make the move along with David Kenfack, CTFS-SIGEO Africa Program coordinator. Davies sees the need for increased presence at the Smithsonian in Washington, D.C. as the network continues to build partnerships within different Smithsonian units.

The scale and intensity of the CTFS-SIGEO research program remains unprecedented in forest science. Scientists monitor the growth and survival of about 4.5 million trees of approximately 8,500 species in 21 different countries. The work aims to increase the scientific understanding of forest ecosystems, guide sustainable forest management and natural-resource policy, monitor the impacts of climate change, and build capacity in forest science. Most recently CTFS-SIGEO added the Lilly-Dickey Woods–a 550-acre forest in Brown County Indiana that is a research and teaching preserve for Indiana University–to its network of forest research plots.

Because of its extensive biological monitoring, unique databases, and the expertise of its partners, CTFS-SIGEO enhances society’s ability to evaluate and respond to the impacts of global climate change. Monitoring so many forest plots at once is providing a comprehensive, yet locally detailed perspective on how the world’s forests are being transformed by global change. Research on tropical forest dynamics continues, but is joined by new initiatives studying carbon fluxes, temperate forests, ecosystem services, and biodiversity. CTFS-SIGEO and its many institutional partners are leveraging huge intellectual horsepower to transform our understanding of forest-ecosystem structure and function. The network has been so successful that the Smithsonian is now planning to extend its system of earth observatories to the near shore marine realm. –Source: The Plant Press, newsletter of the Department of Botany, National Museum of Natural History.

Killer carnivores: Titanoboa vs. T-Rex — Premieres April 1 on Smithsonian Channel

John Barrat — Thu, 22 Mar 2012 13:52:33 +0000

Largest snake the world has ever seen is being brought back to life by Smithsonian Channel

John Barrat — Tue, 06 Mar 2012 12:58:31 +0000

Slithering in at 48 feet long and weighing an estimated one-and-a-half tons, the largest snake the world has ever seen is being brought back to life. Sixty million years ago, in the mysterious era after the mass extinction of the dinosaurs, scientists believe that a colossal snake related to modern boa constrictors ruled a lost world. With exclusive access to what one scientist called “a once-in-a-lifetime discovery,” Smithsonian Channel(TM) will tell the extraordinary true story in TITANOBOA: MONSTER SNAKE, a two-hour special premiering Sunday, April 1 at 8 p.m. ET/PT.

The startling discovery of Titanoboa was made by a team of scientists working in one of the world’s largest open-pit coal mines at Cerrejon in La Guajira, Colombia. It is a snake that dwarfs the largest anaconda found today, and it has the size and character to challenge T-Rex in the public’s imagination.

The story behind this significant scientific revelation began in 2002, when a Colombian student visiting the coal mine made an intriguing discovery: a fossilized leaf that hinted at an ancient rainforest from the Paleocene epoch. Over the following decade, collecting expeditions led by the Smithsonian Tropical Research Institute and the Florida Museum of Natural History, University of Florida opened a unique window into perhaps the first rainforest on Earth. Fossil finds included giant turtles and crocodiles, as well as the first known bean plants and some of the earliest banana, avocado and chocolate plants. But their most spectacular discovery was the fossilized vertebrae of a previously undiscovered species of snake, one so large it defied imagination.

Together with their research teams, Jonathan Bloch of the Florida Museum of Natural History, University of Florida and Carlos Jaramillo of the Smithsonian Tropical Research Institute, joined forces with one of the world’s foremost experts in ancient snakes, Jason Head of the University of Nebraska, to unlock the mysteries of this ancient time and discover exactly how Titanoboa appeared, lived and hunted. The fossilized remains revealed that, after the extinction of the dinosaurs, the tropics were warmer than today and witnessed the birth of the South American rainforest, in which huge creatures battled it out to become the planet’s top predators. Dominating this era was Titanoboa, the undisputed largest snake in the history of the world.

Most of the fossil record of ancient snakes is comprised of vertebrae like the one that launched the Titanoboa investigation. Snake skulls are almost never found as they are extremely fragile and usually disintegrate – making it almost impossible to create a full and accurate picture of these extinct creatures. But during the filming of TITANOBOA: MONSTER SNAKE, the scientists managed to uncover not just one, but fragments of three skulls, allowing them to derive for the first time what this ancient giant looked like.

A scientifically accurate, life-sized replica of Titanoboa appears in the film and will go on display for the first time at the National Museum of Natural History beginning March 30, 2012. The exhibition will travel to museums across the country beginning in fall 2013. Titanoboa: Monster Snake is a collaboration between the Florida Museum of Natural History at the University of Florida in Gainesville, the University of Nebraska-Lincoln, and the Smithsonian Tropical Research Tropical Research Institute, and is circulated by the Smithsonian Institution Traveling Exhibition Service.

The two-hour special explores how this monster snake would have lived by visiting its living cousins, boa constrictors and anacondas, in the Florida Everglades and the Venezuelan Grasslands. The scientists’ research yields some intriguing and terrifying insights, including the climate in which it lived and size of the snake. All of these clues come together to paint a picture of Titanoboa’s world, which is brought back to life in stunning CGI. Here we see how the colossal snake ruled as an ancient apex predator among a land of tropical mega-beasts.

TITANOBOA: MONSTER SNAKE follows the scientific sleuths back to the mine, into the labs, and on an expedition to understand modern giant constrictors. It creates a picture of the then largest predator on the planet – a creature that until now has only populated fiction and nightmares, but can finally be displayed as a marvel of nature.

Fancy footwork and non-stick leg coating helps spiders not stick to their own webs

John Barrat — Thu, 01 Mar 2012 13:21:19 +0000

Researchers at the Smithsonian Tropical Research Institute and University of Costa Rica studying why spiders do not stick to their own sticky webs have discovered that a spider’s legs are protected by a covering of branching hairs and by a non-stick chemical coating. Their results are published online in the journal, Naturwissenschaften.

Image right: This mature female golden silk spider had just contacted the sticky line with her right leg IV and was about to extend this leg, thereby pulling additional line from her spinnerets. (Photo by C. Frank Starmer)

They also observed that spiders carefully move their legs in ways that minimize adhesive forces as they push against their sticky silk lines hundreds to thousands of times during the construction of each orb.

The web-weaving behavior of two tropical species, Nephila clavipes and Gasteracantha cancriformis, was recorded with a video camera equipped with close-up lenses. Another video camera coupled with a dissecting microscope helped to determine that individual droplets of sticky glue slide along the leg’s bristly hair, and to estimate the forces of adhesion to the web. By washing spider legs with hexane and water, they showed that spiders’ legs adhered more tenaciously when the non-stick coating was removed.

( “Spiders avoid sticking to their webs: clever leg movements, branched drip-tip setae, and anti-adhesive surfaces” by R.D. Briceño and W.G. Eberhard. 2012. Naturwissenshaften. DOI 10.1007/s00114-012-0901-9. Published online: 1 March 2012.)

Wayne Clough & Carlos Jaramillo, at a research site near the Panama Canal.

John Barrat — Thu, 16 Feb 2012 18:31:09 +0000

Smithsonian Secretary Wayne Clough, left, talks with Carlos Jaramillo, scientist at the Smithsonian Tropical Research Institute in Panama, at a research site near the Panama Canal. Jaramillo and his team are collecting and examining prehistoric fossils exposed during the recent widening of the Canal. To date, they have discovered the fossils of a 12-inch-tall horse, a tiny camel, huge rhinos, turtles and trees 17- to 23-million-years-old. They have also uncovered evidence indicating the Isthmus of Panama did not emerge three million years ago, but as early as 22 million years ago. (Photo by Johnny Gibbons)

Video: Meet our Scientist–Mark Torchin tracks invasive marine species and their parasites in Panama

John Barrat — Thu, 02 Feb 2012 14:03:02 +0000

Ancient popcorn discovered in Peru

John Barrat — Wed, 18 Jan 2012 13:06:35 +0000

People living along the coast of Peru were eating popcorn 2,000 years earlier than previously reported and before ceramic pottery was used there, according to a new paper in the Proceedings of the National Academy of Sciences co-authored by Dolores Piperno, curator of New World archaeology at the Smithsonian’s National Museum of Natural History and emeritus staff scientist at the Smithsonian Tropical Research Institute.

Image right: These ancient corn cobs date roughly from 6,500-4,000 years ago. A is Proto-Confite Morocho race; B, Confite Chavinense maize race; and C is Proto-Alazan maize race.. (Photo by Tom Dillehay)

Some of the oldest known corncobs, husks, stalks and tassels, dating from 6,700 to 3,000 years ago were found at Paredones and Huaca Prieta, two mound sites on Peru’s arid northern coast. The research group, led by Tom Dillehay from Vanderbilt University and Duccio Bonavia from Peru’s Academia Nacional de la Historia, also found corn microfossils: starch grains and phytoliths. Characteristics of the cobs—the earliest ever discovered in South America—indicate that the sites’ ancient inhabitants ate corn several ways, including popcorn and flour corn. However, corn was still not an important part of their diet.

Image left: Wild forms of Zea mays are called ‘teosinte’. Over time, selective breeding modifies teosinte’s few fruitcases (left) into modern corn’s rows of exposed kernels (right). (Photo courtesy John Doebley.).

“Corn was first domesticated in Mexico nearly 9,000 years ago from a wild grass called teosinte,” Piperno says. “Our results show that only a few thousand years later corn arrived in South America where its evolution into different varieties that are now common in the Andean region began. This evidence further indicates that in many areas corn arrived before pots did and that early experimentation with corn as a food was not dependent on the presence of pottery.”

Understanding the subtle transformations in the characteristics of cobs and kernels that led to the hundreds of maize races known today, as well as where and when each of them developed, is a challenge. Corncobs and kernels were not well preserved in the humid tropical forests between Central and South America, including Panama—the primary dispersal routes for the crop after it first left Mexico about 8,000 years ago.

“These new and unique races of corn may have developed quickly in South America, where there was no chance that they would continue to be pollinated by wild teosinte,” Piperno says. “Because there is so little data available from other places for this time period, the wealth of morphological information about the cobs and other corn remains at this early date is very important for understanding how corn became the crop we know today.”

“Preceramic corn from Pardones and Huaca Prieta, Peru,” Grobman, A., Bonavia, D., Dillehay, T.D., Piperno, D.R., Iriarte, J., Holst, I. 2012. . PNAS early online edition, week of Jan. 16, 2012.