Newly Discovered Ankylosaur Dinosaur Is 'Biological Version Of An Army Tank'

A husband and wife team of American paleontologists has discovered a new species of dinosaur that lived 112 million years ago during the early Cretaceous of central Montana.

The new dinosaur, a species of ankylosaur, is documented in the October issue of the Canadian Journal of Earth Sciences. Ankylosaurs are the biological version of an army tank. They are protected by a plate-like armour with two sets of sharp spikes on each side of the head, and a skull so thick that even 'raptors' such as Deinonychus could leave barely more than a scratch.

Bill and Kris Parsons, Research associates of the Buffalo Museum of Science, found much of the skull of the newly described Tatankacephalus cooneyorum resting on the surface of a hillside in 1997. Because the skull was 90% complete, it was possible to justify this fossil as a new species.

"This is the first member of Ankylosauridae to be found within the Early Cretaceous Cloverly Geologic Formation," said Bill Parsons, who characterized the fossil as a transitional evolutionary form between the earlier Jurassic ankylosaurs and the better known Late Cretaceous ankylosaurs.

The skull is heavily protected by two sets of lateral horns, two thick domes at the back, and smaller thickenings around the nasal region. "Heavy ornamentation and horn-like plates would have covered most of the dorsal surface of this dinosaur" said Bill Parsons.

"For years, Bill and Kris have been collecting fossils from a critical time in Earth's history, and their hard work has paid off," said Lawrence Witmer, professor of paleontology at Ohio University who was not involved with this study. "This is a really important find and gives us a clearer view of the evolution of armored dinosaurs. But this is just the first; I'm sure, of what will be a series of important discoveries from this team."

Parsons also illustrated the dermal armour of this new species based on the theory by Museum of the Rockies paleontologist John R. Horner that there was an outer keratinous sheathing on it as found in modern turtle shells and bird beaks. In his new reconstruction, Parsons suggests that Tatankacephalus exhibited complex and colorful patterns rather than the dull appearance suggested in earlier ankylosaur portraits. "According to Horner's theory, many other dinosaurs also had this kind of sheathing and also may have been diversely colored," said Parsons.

As to its name, the broad, short horns on the back of its skull resemble the horns found on a modern buffalo skull and Tatankacephalus loosely translates as 'Buffalo head.' Parsons also noted, "of course any further allusions to the city of Buffalo are completely intentional as well."

Genome Of Microbe Silently Shaping Ecology Of Ocean Dead Zones Described

Among the many changes in the ocean is the expansion of oxygen-deficient or oxygen minimum zones (OMZs), also known as dead zones, which affect the processes by which carbon is captured and sequestered on the seafloor and alter the microbial activities that impact the rate and magnitude of ocean carbon sequestration. Despite the importance of these effects, very little is known about the metabolism of OMZ microbes and how they respond to environmental changes.

In the Oct. 23 issue of the journal Science, researchers from the University of British Columbia and the U.S. Department of Energy Joint Genome Institute (DOE JGI) describe the metagenome of an abundant but uncultivated microbe, known as SUP05, that is silently helping to shape the ecology of OMZs worldwide. Researchers studied the microbe in Saanich Inlet, a fjord on the coast of Vancouver Island, British Columbia, Canada. The fjord undergoes a seasonal cycle of stratification and deep water renewal, creating strong water column gradients that make it an ideal "living lab" to study microbial communities adapted and specialized to thrive under low oxygen conditions such as those found in OMZs. To chart the SUP05 metagenome, genetic material was recovered directly from environmental samples encompassing the entire microbial community of Saanich Inlet during different stages of water column stratification and deep-water renewal.

"To our surprise the most abundant organism in the oxygen-depleted waters was this SUP05 bug," said the paper's senior author Steven Hallam, Assistant Professor at the University of British Columbia. "We obtained enough DNA sequence coverage from the community of microbes to actually assemble a continuous stretch representing what we are calling the SUP05 metagenome -- it's a composite of the entire SUP05 population spanning the various environmental samples that we sequenced."

Susannah Tringe, a metagenomics scientist at the DOE JGI, said that the OMZs are sinks for an essential nutrient that marine organisms need to survive--nitrogen--as well as sources for the greenhouse gases methane and nitrous oxide. "By studying the genomes of the uncultivated microbes found in OMZs, we can better understand how they participate in global geochemical cycles such as the carbon and nitrogen cycles," she said.

Hallam described SUP05 as a paradoxical organism. "Based on genomic analysis and field observations, it provides important ecosystem services but it also produces byproducts that may have negative consequences with respect to climate change," he said. "Specifically, SUP05 removes toxic sulfides from the water, and fixes carbon dioxide but we also think it's producing nitrous oxide, which is a more potent greenhouse gas than either carbon dioxide or methane."

The researchers found that SUP05 is closely related to sulfur-eating gill symbionts of deep sea clams and mussels although unlike them, it utilizes nitrate rather than oxygen in its energy metabolism. A comparative analysis of SUP05 and symbiont genomes also revealed that 35 percent of the SUP05 genome is unique, involved in helping the bacteria adapt to changing environmental conditions such as the seasonal increase and decrease of oxygen levels in Saanich Inlet, and the shifting balance of the nitrate and sulfide levels that are its key energy resources.

"As habitat range expands due to global warming, blooming SUP05 populations have the potential to help offset rising carbon dioxide levels that ultimately lead to ocean acidification," Hallam said. He added that SUP05 and its relatives will become increasingly important agents as OMZ expansion and intensification continues to unfold, providing researchers with a biological indicator useful in monitoring the changing state of the global ocean.

The researchers plan to do further time course and metabolic monitoring studies in Saanich Inlet in conjunction with the Victoria Experimental Network Under the Sea (VENUS) cabled observatory program to better constrain the ecological roles of SUP05 and other, less abundant community members. Additionally, they hope to use the time-resolved studies in Saanich Inlet as a basis for comparison in the context of another CSP project of Hallam's that was approved earlier this year and focuses on an extensive OMZ in the eastern North Pacific Ocean.

"Just as cyanobacteria play an essential role in producing atmospheric oxygen; in future oceans this could be one of those organisms that play similarly integral roles, albeit with different ecological outcomes," Hallam said. An overview of the project can be viewed at: http://www.cmde.science.ubc.ca/hallam/index.php.

The project is part of the DOE JGI's Community Sequencing Program established in 2004 to take on large-scale genomics efforts in support of DOE mission areas, including characterizing the biological and environmental processes involved in carbon cycling.

Biofuel Displacing Food Crops May Have Bigger Carbon Impact Than Thought

A report examining the impact of a global biofuels program on greenhouse gas emissions during the 21st century has found that carbon loss stemming from the displacement of food crops and pastures for biofuels crops may be twice as much as the CO2 emissions from land dedicated to biofuels production. The study, led by Marine Biological Laboratory (MBL) senior scientist Jerry Melillo, also predicts that increased fertilizer use for biofuels production will cause nitrous oxide emissions (N2O) to become more important than carbon losses, in terms of warming potential, by the end of the century.

Using a global modeling system that links economic and biogeochemistry data, Melillo, MBL research associate David Kicklighter, and their colleagues examined the effects of direct and indirect land-use on greenhouse gas emissions as the production of biofuels increases over this century. They report their findings in the October 22 issue of Science Express.

Direct land-use emissions are generated from land committed solely to bioenergy production. Indirect land-use emissions occur when biofuels production on cropland or pasture displaces agricultural activity to another location, causing additional land-use changes and a net increase in carbon loss.

No major countries currently include carbon emissions from biofuel-related land-use changes in their carbon loss accounting and there is concern about the practicality of including such losses in a system designed to reduce fossil-fuel emissions. Moreover, methods to assess indirect land-use emissions are controversial. All quantitative analyses to date have either ignored indirect emissions altogether, considered those associated from crop displacement from a limited area, confused indirect emissions with direct or general land-use emissions, or developed estimates based on a static framework of today's economy.

Using a modeling system that integrates global land-use change driven by multiple demands for land and that includes dynamic greenhouse-gas accounting, Melillo and his colleagues factored in a full suite of variables, including the potential of net carbon uptake from enhanced land management, N2O emissions from the increased use of fertilizer, environmental effects on carbon storage, and the economics of land conversion.

"Our analysis, which we think is the most comprehensive to date, shows that direct and indirect land-use changes associated with an aggressive global biofuels program have the potential to release large quantities of greenhouse gases to the atmosphere," says Melillo.

Melillo and his colleagues simulated two global land-use scenarios in the study. In Case 1, natural areas are converted to meet increased demand for biofuels production land. In Case 2, there is less willingness to convert land and existing managed land is used more intensely. Both scenarios are linked to a global climate policy that would control greenhouse gas emissions from fossil fuel sources to stabilize CO2 concentrations at 550 parts per million, a target often talked about in climate policy discussions. Under such a climate policy, fossil fuel use would become more expensive and the introduction of biofuels would accelerate, ultimately increasing the size of the biofuels industry and causing additional effects on land use, land prices, and food and forestry production and prices.

The model predicts that, in both scenarios, land devoted to biofuels will become greater than the total area currently devoted to crops by the end of the 21st century. Case 1 will result in more carbon loss than Case 2, especially at mid-century. In addition, indirect land use will be responsible for substantially greater carbon losses (up to twice as much) than direct land use.

"Large greenhouse gas emissions from these indirect land-use changes are unintended consequences of a global biofuels program; consequences that add to the climate-change problem rather than helping to solve it," says Melillo "As our analysis shows, these unintended consequences are largest when the clearing of forests is involved."

In their model, Melillo and his colleagues also simulated N2O emissions from the additional fertilizer that will be required to grow biofuel crops in the future. They found that over the century, N2O emissions will surpass CO2 in terms of warming potential. By 2100, Melillo and his team estimate that in both study scenarios, biofuels production will account for more than half of the total N2O emissions from fertilizer. "Best practices for the use of nitrogen fertilizer, such as synchronizing fertilizer application with plant demand, can reduce N2O emissions associated with biofuels production," the scientists say.

Finding The ASX200 For Marine Ecosystems

Researchers are building the environmental equivalent of the ASX200 as a means of monitoring the health of Australian marine ecosystems.

The state of an ecosystem can be understood by measuring the right ecological characteristics, just as the ASX200 index shows the state of the Australian stock market by following 200 selected stocks.

CSIRO Wealth from Oceans Flagship scientist Dr Keith Hayes, one of the leaders of the project, says the difficult part is selecting which characteristics to track.

"Ecosystems respond to multiple pressures and threats in complex ways," Dr Hayes says.

"Identifying reliable and robust indicators of change from among the many species and characteristics of the system is a challenging task."

In a pilot project undertaken for the Department of Environment, Water, Heritage & the Arts (DEWHA) last year, CSIRO identified indicators for five 'key ecological features' named by the Commonwealth Government for the South-West Marine Region off Western Australia's coast.

Key ecological features chosen for this study included the Perth Canyon and large ocean eddies.

The indicators were different for each feature, but they included things like numbers of sea birds, area of coral compared to algae, and phytoplankton size.

Such indicators will help provide a firm scientific basis to feed into State of the Environment reporting at regional, national and international scales.

"Indicators are an important topic in environmental circles right now as they help us make better decisions about managing the environment," Commonwealth Environment Research Facilities (CERF) Marine Biodiversity Hub director Professor Nic Bax says.

CSIRO's approach uses qualitative modelling, supported by asset and threat mapping, to understand the drivers and pressures on ecological features, and to predict how these features will respond to changes over the next five to 15 years.

"Having selected a suite of indicators, the next challenge is to measure them and test how they are predicted to change when subject to processes such as climate change, industrial development and fishing pressures," Dr Hayes says.

"We were really pleased with the results of the pilot project and have now embarked on a two-year program with DEWHA to develop a list of ecological indicators for the rest of Australia's marine territory."

This new project is in addition to the current CERF program.

The work will be presented at the Nationally Relevant Environmental Monitoring workshop in Canberra October 20 and 21, which is hosted by CSIRO and the Marine Biodiversity Hub.

The Marine Biodiversity Hub is funded through the CERF program, an Australian Government initiative supporting research with a strong public good focus.

Sage-grouse Populations In US Intermountain West May Be Threatened By Energy Development, Study Predicts

A study released October 14th in the current issue of the peer-reviewed journal PLoS ONE sheds new light on oil and gas development potential in the Intermountain West. Maps accompanying the study show the impacts to greater sage-grouse populations in relation to potential energy development. If business as usual continues and more forward-thinking development strategies are not considered, sage-grouse populations will decline an additional 7 to 19 percent, the study's authors predict.

 

Prepared by scientists from The Nature Conservancy, the National Audubon Society, and the University of Montana, the study created a tool to understand the cumulative impacts of energy development on species in the West. Agencies can use the study's findings to determine how best to pursue energy independence while maintaining quality habitat that is critical to imperiled sage-grouse populations as well as a host of other species, including iconic big game of the West.

"This study illustrates how impacts to sensitive species, in this example sage-grouse, can be used to forecast biological trade-offs of newly proposed or ongoing development plans," said study co-author Dr. Kevin Doherty, Senior Ecologist at the National Audubon Society. "A 7-19% impact to sage-grouse in their eastern range from just one of the host of issues causing their declines, highlights the need for scientifically credible conservation planning tools to balance natural resource development with wildlife conservation."

Sage-grouse populations are considered indicators of ecosystem health and have been closely monitored by state game and fish agencies over the past decade. The greater sage-grouse is currently a candidate for Endangered Species listing -- a result that would have far reaching implications for a wide range of industries in the region.

"Sage-grouse are useful in prioritizing conservation because their abundance is indicative of large and intact shrub-dominated grasslands, the most endangered ecosystem in North America," said study co-author, Dr. David Naugle, Associate Professor, University of Montana. "Challenges with sage-grouse are a harsh reminder that the value of small-scale conservation actions may be negated if large-scale cumulative impacts are ignored."

The new study and its detailed maps of the Intermountain West indicates that future oil and gas drilling could impact up to 9.1 million acres of sagebrush shrub lands and 2.7 million acres of grasslands -- key sage-grouse habitat.

Global demand for energy has increased by more than 50 percent in the last half century, and a similar increase is projected between 2007 and 2030. Much of our domestic demand will be served by new exploration in the western US -- making the health of wildlife in the West, such as sage-grouse, an issue of national importance.

"The Conservancy and the Audubon Society have been jointly working with state and federal agencies to proactively identify areas of high biological value that may impact oil and gas operations," said study lead author Holly Copeland, spatial ecologist, with the Nature Conservancy in Wyoming. "Linking wildlife impacts with predictive oil and gas models will provide tools to decision makers charged with meeting the challenge of maintain healthy wildlife populations while responsibly developing domestic energy resources."

This study was supported with funding from the Liz Claiborne Art Ortenberg Foundation (http://www.lcaof.org), The Nature Conservancy, National Audubon Society, and the University of Montana.

Female Choice Benefits Mothers More Than Offspring

The great diversity of male sexual traits, ranging from peacock's elaborate train to formidable genitalia of male seed beetles, is the result of female choice. But why do females choose among males? In a new study published October 22 in Current Biology, researchers from Uppsala University found no support for the theory that the female choice is connected to "good genes".

The great diversity of male sexual traits, ranging from peacock's elaborate train to formidable genitalia of male seed beetles, is the result of female choice. But why do females choose among males? Remarkably, there is no consensus among biologists over the key question why females choose among males. At the heart of this debate lie two distinct possibilities -- that female choosiness is beneficial to the females themselves or that female choice traits are favoured because of 'good genes' that males contribute to female's offspring.

Across animal kingdom, females often resist male advances and only a small fraction of mating attempts result in copulations. Mating is costly, and one straightforward explanation for female resistance is that non-resistant females will suffer a reduction in their fitness. However, by resisting mating attempts, females are selecting for most 'persistent' males. Could it be that offspring of such 'persistent' males have higher fitness? If yes, female resistance can be viewed as a way of selecting for males that provide their offspring with 'good genes'.

We manipulated female choosiness by altering female ability to reject unwanted males in Adzuki beetle. Female beetles are constantly harassed by ardent males and thwart male mating attempts by vigorously kicking the unwanted suitors with their hind legs. We fitted females with prongs that reduced male ability to impose copulations. Alternatively, we reduced females' ability to resist copulations by shortening their hind legs. Females with increased ability to reject male mating attempts had much higher fitness than females whose resistance was reduced. What about the 'good genes'?

- We found no support for the idea that increased female resistance to mating results in sons that are more successful in competition with other males, or in more fertile daughters. Hence, female resistance is mostly beneficial to the female herself, while inadvertent selection for male 'persistence' plays a minor role, says Alexei Maklakov, who led the study.

GIANT SNAKE PICTURES: Alien Species Invading U.S.?

October 14, 2009--The world's heaviest snake, the green anaconda is one of nine huge alien snake species that may wreak havoc if they take hold in the United States, according to a U.S. Geological Survey (USGS) report released this week. (Read full story: "Alien Giant Snakes Threaten to Invade Up to 1/3 of U.S.")

The giant snake (pictured in the Peruvian Amazon) can reach lengths of 23 feet (7 meters) and weigh in at 550 pounds (227 kilograms). The olive-green reptiles would flourish in the Florida Peninsula and in southern Texas, regions that have climates similar to the anaconda's native South American habitat, the study authors say.

USGS scientists rated the nine snakes based on the risk of the reptiles becoming established in the U.S., which is most likely to happen in areas where pet snakes are commonly released into the wild. The green anaconda is among four species considered medium risks--the species is not popular as a pet, and fewer than 500 of the animals arrive in the U.S. each year from South America, according to the report. Though green anacondas have been found in the wild in Florida, there is no evidence they are breeding.

The five in the following gallery are the true giants, but the USGS scientists also studied four "look alike" species: the southern African python, DeSchauensee's anaconda, the Beni anaconda, and the yellow anaconda.

Kenneth Krysko, senior herpetologist at the Florida Museum of Natural History in Gainesville, called the report "extremely thorough." But it came as "no real surprise that giant constrictors can potentially be a threat to not only the wildlife here but to the humans," added Krysko, who was not involved in the report.

Green anacondas have not been known to attack humans, but their tastes vary widely, including fish, turtles, dogs, and tapirs. The snakes ambush prey from the water and constrict them with an immediately deadly, bone-crushing force. (Watch an anaconda hunt the world's largest rodent.)

Ancient Earth's Magnetic Field Was Structured Like Today's Two-pole Model

Princeton University scientists have shown that, in ancient times, the Earth's magnetic field was structured like the two-pole model of today, suggesting that the methods geoscientists use to reconstruct the geography of early land masses on the globe are accurate. The findings may lead to a better understanding of historical continental movement, which relates to changes in climate.

By taking a closer look at the 1.1 billion-year-old volcanic rocks on the north shore of Lake Superior, the researchers have found that Earth's ancient magnetic field was a geocentric axial dipole -- essentially a large bar magnet centered in the core and aligned with the Earth's spin axis.

Some earlier studies of these rocks had led other teams to conclude that the magnetic field of the ancient Earth had a far more complex structure -- some proposing the influence of four or even eight poles -- implying that present models of the supercontinents that relied on paleomagnetic data and an axial dipole assumption were wrong.

The report, which will appear in the October issue of Nature Geoscience, says that previous efforts to interpret the ancient geomagnetic field in rocks from North America were confused by the rapid migration of the continent toward the equator in the distant past.

The researchers "neatly lay to rest the long-standing controversy over the nature of Earth's magnetic field 1.1 billion years ago," writes geoscientist Joseph Meert of the University of Florida in an essay that accompanies the report.

"In this paper, we show that Earth's magnetic field has been more stable in the past than originally believed," said Adam Maloof, an assistant professor of geosciences at Princeton and one of the paper's authors.

The Earth's magnetic field wraps around the globe, shielding life from harmful cosmic rays. It is emanated by the Earth's iron core and is shaped by a multitude of factors, including the spinning of the Earth and circulatory motion influenced by the Earth's rotation and temperature differences between the inner core's outer layers and the lower mantle.

The researchers obtained magnetic measurements from a thick stack of lava flows in the Lake Superior region. The lavas erupted when geologic forces attempted to tear apart central North America forming the Keweenawan Rift. The researchers used the tiny magnetic minerals within the volcanic rocks to record the orientation of the geomagnetic field at the time the rocks erupted onto the Earth's surface. By knowing how those grains pointed to the magnetic field of that time, the scientists could deduce the latitude where they were located when the lava flows erupted and cooled. The grains pointed to where "paleo-north" was for each rock.

Studying layers of the basaltic lava flows, they used the information to track how the Earth's magnetic poles have "flipped" over the eons, with the North Magnetic Pole becoming the South Magnetic Pole and vice versa. The team studied three of these reversals that occurred over a few million years.

The scientists plan to use the data to better understand how continents moved in the distant past, massing to form supercontinents. "We needed to be able to have a working model of how the geomagnetic field behaved in the past if we are going to talk about where plates have moved, how fast they've moved and how ancient supercontinents were configured," said Nicholas Swanson-Hysell, a graduate student at Princeton and the first author on the paper.

Knowing the proper location of continents is key to understanding the climate of any era, Maloof said, because the shape and location of continents affect ocean currents, global average temperatures and wind patterns. And by understanding in detail what Earth's climate was like in ancient times, he noted, scientists can better comprehend the climate of today and make more accurate projections for the future.

According to scientific reconstructions, a supercontinent known as Rodinia existed between 1 billion and 800 million years ago. The extreme cooling of the global climate about 700 million years ago and the rapid evolution of primitive life during subsequent periods are often thought to have been triggered by the breaking up of Rodinia.

Rodinia predated a more recently created supercontinent called Pangaea, which came together about 300 million years ago. Scientists have pieced Rodinia together by comparing rocks with similar geological features that are now widely dispersed.

Knowing that they have confirmed the structure of the Earth's magnetic field at that time gives Maloof and Swanson-Hysell the confidence to learn more about the supercontinent and that epoch.

"For the past 30 years, scientists have feared that the geometry of Earth's field was complex and varied," Maloof said. "Such a complex field made it very hard for people to reconstruct the ancient geography of the planet because they could not rely on a predictable field. We show that these fears were unfounded -- at least for 1.1 billion years ago -- and that the evidence for a complex ancient field was an artifact of the way rocks had been sampled."

Other researchers on the paper included: Benjamin Weiss of the Massachusetts Institute of Technology; and David Evans of Yale University.

The research was funded by the National Science Foundation, Sigma Xi, Agouron Institute and Princeton University.

UN wildlife body to mull bluefin tuna trade ban

GENEVA (AFP) – A proposal to place Atlantic and Mediterranean bluefin tuna, a popular sushi staple, on world's most endangered species list has been made to CITES, the UN wildlife trade organisation said Wednesday.

The proposal tabled by Monaco, which could result in a ban in the international trade of the fish, will be considered during the meeting of the convention's 175 state members in Qatar next year, according to official documents seen by AFP.

However, it is unlikely to enjoy the full support of European Union countries, which in September voted down plans for the ban.

"All the countries around the Mediterranean came out against" any ban on trade in the fish, a European Union source said in September.

The EU has however, tabled a proposal to limit the trade of porbeagle sharks, or Lamna nasus, by calling for them to be added to Appendix II -- a list of species that could become extinct if trade in the species is not tightly controlled.

"Unsustainable target fisheries for Lamna nasus in parts of its range have been driven by international trade demand for its high value meat," said the European Union in its submission.

"The meat and fins are of high quality and high value in international trade," it added, targeting North and Southwest Atlantic and Mediterranean stocks.

Demand for sharks' fins, a Chinese delicacy, has hurt stocks of such sharks.

CITES spokesman Juan Carlos Vasquez said the UN agency is expecting to receive a separate proposal on other shark species before the midnight Wednesday deadline for submissions to be sent for consideration during next year's meeting.

Other proposals submitted included those from Tanzania and Zambia which call for the African elephant to be downgraded from the list of most endangered species to Appendix II, thereby lifting a ban on ivory trade.

A proposal to limit trade of some coral species is also expected to be filed, added Vasquez.

In 2007, the 175-member Convention on International Trade in Endangered Species placed 26 species of corals on its Appendix II, protecting them from the unregulated trade which has decimated coral stocks around the world.

But days later, the member nations back-tracked and removed restrictions they had imposed.

 Smithsonian researchers working in Colombia's Cerrejón coal mine have unearthed the first megafossil evidence of a neotropical rainforest. Titanoboa, the world's biggest snake, lived in this forest 58 million years ago at temperatures 3-5 C warmer than in rainforests today, indicating that rainforests flourished during warm periods.
"Modern neotropical rainforests, with their palms and spectacular flowering-plant diversity, seem to have come into existence in the Paleocene epoch, shortly after the extinction of the dinosaurs 65 million years ago," said Carlos Jaramillo, staff scientist at the Smithsonian Tropical Research Institute. "Pollen evidence tells us that forests before the mass extinction were quite different from our fossil rainforest at Cerrejón. We find new plant families, large, smooth-margined leaves and a three-tiered structure of forest floor, understory shrubs and high canopy."
Historically, good rock exposures and concentrated efforts by paleontologists to understand the evolution of neotropical rainforests—one of the most awe-inspiring assemblages of plant and animal life on the planet—have been lacking. "The Cerrejón mining operation is the first clear window we have to see back in time to the Paleocene, when the neotropical rainforest was first developing," said Scott Wing, a paleontologist from the Smithsonian's National Museum of Natural History.
Some of the more than 2,000 fossil leaves, including the compound leaves and pods of plants in the bean family and leaves of the hibiscus family are among the oldest, reliable evidence of these groups. This was the first time that the plant families Araceae, Arecaceae, Fabaceae, Lauraceae, Malvaceae and Menispermaceae, which are still among the most common neotropical rainforest families, all occurred together.
Many newcomers to modern rainforests remark that the leaves all look the same, a reasonable observation given that most have smooth margins and long "drip-tips" thought to prevent water from accumulating on the leaf surface.
S. Joseph Wright, senior scientist at STRI, has noted that all of the areas in the world today with average yearly temperatures greater than 28 C are too dry to support tropical rainforests. If tropical temperatures increase by 3 C by the end of this century as predicted in the 2007 report of the Intergovernmental Panel on Climate Change, "We're going to have a novel climate where it is very hot and very wet. How tropical forest species will respond to this novel climate, we don't know," said Wright.
Based on leaf shape and the size of the cold-blooded Titanoboa, Cerrejón rainforest existed at temperatures up to 30-32 C and rainfall averages exceeded 2500 mm per year.
But Titanoboa's rainforest was not as diverse as modern rainforests. Comparison of the diversity of this fossil flora to modern Amazon forest diversity and to the diversity of pollen from other Paleocene rainforests revealed that there are fewer species at Cerrejón than one would expect. Insect-feeding damage on leaves indicated that they could have been eaten by herbivores with a very general diet rather than insects specific to certain host plants.
"We were very surprised by the low plant diversity of this rainforest. Either we are looking at a new type of plant community that still hadn't had time to diversify, or this forest was still recovering from the events that caused the mass extinction 65 million years ago," said Wing. "Our next steps are to collect and analyze more sites of the same age from elsewhere in Colombia to see if the patterns at Cerrejón hold, and study additional sites that bracket the Cretaceous mass extinction, in order to really understand how the phenomenal interactions that typify modern rainforests came to be."