Image right: The thick fossil carapace of a newly discovered prehistoric turtle.

Cerrejonemys wayuunaiki takes its genus name from Cerrejón, and emys—Greek for turtle. Its species name is the language spoken by the Wayuu people who live on the Guajira Peninsula in northeastern Colombia near the mine. About as thick as a standard dictionary, this turtle’s shell may have warded off attacks by the Titanoboa, thought to have been the world’s biggest snake, and by crocodile-like creatures living in its neighborhood 60 million years ago.

Image left: Carlos Jarmillo with turtle specimens in the Cerrejón coal mine.

“The fossils from Cerrejón provide a snapshot of the first modern rainforest in South America—after the big Cretaceous extinctions and before the Andes rose, modern river basins formed and the Panama land bridge connected North and South America,” explains Carlos Jarmillo, staff scientist at the Smithsonian who studies the plants from Cerrejón.

“We are still trying to understand why six of this turtle’s modern relatives live in the Amazon, Orinoco and Magdalena river basins of South America and one lives in Madagascar,” explains Edwin Cadena, first author of the study and a doctoral candidate  at North Carolina State University. This discovery “closes an important gap in the fossil record and supports the idea that the group originated near the tip of South America before the continent separated from India and Madagascar more than 90 million years ago.”

Image right: An artist’s conception of the giant prehistoric snake Titanoboa. (Illustration by Jason Bourque)

Cadena will characterize two more new turtle species and analyze the histology of fossil turtle bones from the Cerrejón site. “I hope this will give us an even better understanding of turtle diversity in the region and some important clues about the environment where they lived.”

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Illustration: Eurasian mid Mesozoic scorpionflies feeding on gymnosperm ovulate organs, each with tubular access to deeper-seated rewards such as nectar or pollination drops. (Illustration by Mary Parrish)

Conrad Labandeira, paleoentomologist at Smithsonian’s National Museum of Natural History, and team members examined both the specialized features of scorpionfly mouthparts and the unique reproductive features of coexisting gymnosperm plants. The proboscis (elongated tubular mouthparts) of these insects, which was up to 1.3 centimeters long, was either hairy or had ridges, and frequently had pads at the tip to suck up fluids, similar to the structure of modern hoverflies, moths and butterflies. The presumed gymnosperm hosts bore deep funnel-like or tubular channels, also up to 1.3 centimeters long, containing nectar-like pollen drops.

The reproductive anatomy of the plants was typically gymnospermous, but show important modifications for insect attraction, similar to modern flowering plants. However the lineages of these plants and their scorpionfly pollinators became extinct during the mid-Cretaceous period (approximately 105 million years ago) just as flowering plants and their newly evolved pollinators, such as moths and butterflies, came on the scene.

Photos: Lichnomesopsyche gloriae (Mecoptera: Mesopsychidae), from the late Middle Jurassic of northeastern China, showing head and  long, hairy proboscis. (Photos by Wenying Wu)

“This exciting discovery now answers the conclusions that paleobotanists were making recently regarding ‘strange’ structures occurring in the ovulate organs of some Mesozoic gymnospermous plants,” said Labandeira. “One such fructification of an extinct Early Cretaceous cheirolepidiaceous conifer family, Alvinia bohemica, is the best example of an anatomically complicated, jerry-rigged device to achieve insect pollination. There were contemporaneous, matching, elongate insect mouthparts, and other evidence, that indicate presence of a gymnosperm-based pollination mode from the deep past.”  

The evolution of this type of elongated mouthpart among insects occurred at least five separate times during a 13-million-year span during the Middle Jurassic period. The pollinating relationship between modern pollinators and flowering plants was an independent evolutionary occurrence, separate from the scorpionfly and gymnosperm plants.

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Photo: This fossil of Anchitherium clarencei, found in the Panama Canal earthworks, is now in the collection of the University of Florida. (Photo courtesy Aldo Rincon)

The discovery significantly extends the southern tip of the known range of this prehistoric animal, and adds to previous fossil evidence discovered in strata from roughly the same period in Florida, Nebraska and South Dakota. It is by far the most complete fossil of a horse collected at the canal site in excavations spanning the last century; characteristics such as the shape of the horse’s teeth indicate it was primarily a forest-dwelling browser. This evidence supports MacFadden’s belief that the habitat of Panama was once a mosaic of relatively dense forest and open woodlands.

The ongoing excavation of the Panama Canal waterway to make the canal wide enough for supersized cargo ships has been a dream come true for Carlos Jaramillo, senior scientist at the Smithsonian Tropical Research Institute in Panama, and his colleagues. Jaramillo, working with the University of Florida and the Panama Canal Authority, organized a team of researchers and students who rush in to map and collect newly exposed fossils in the canal earthworks following large dynamite blasts set off by canal excavators. It was during one of these collecting excursions that Aldo Rincon, a paleontology intern at the Tropical Research Institute, unearthed the fossil teeth of Anchitherium clarencei.

Photo: Following blasting to expand the Panama Canal, geologists and paleontologists organized by the Smithsonian Tropical Research Institute rush in to map, describe and recover any fossils they can find that might reveal more about the prehistoric ecology of Panama.

The Panama Canal excavation site “is one of very few places in the tropics where we have access to fresh outcrops before they are washed away by torrential rains or overgrown by vegetation,” Jaramillo says.

“We expect the fossils that we have been salvaging to resolve some major scientific mysteries, such as: What geological forces combined to create the Panama land bridge? Was the flora and fauna in Panama before the land bridge closed similar to that in North America, or did it include other elements?”

So far, 10 million cubic meters of earth have been removed from the Canal. The pace of operations is about to accelerate as the Canal Authority awards the final bids for the construction of a third set of locks. More information on the Panama Canal Geology Project is available at striweb.si.edu/jaramillo/current_research/index.html.

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Photo: This electron microscope image shows a pollen grain from the Asteraceae family of flowering plants.

The Smithsonian Tropical Research Institute in Panama was recently given a collection of more than 25,000 different pollen grains and spores, each mounted on a microscope slide and labeled according to the plant that produced it. “The collection is worldwide in coverage with an emphasis on plants of the Americas,” explains collection donor Alan Graham, professor emeritus at Kent State University and curator at the Missouri Botanical Garden.

Graham began the collection in 1954, gathering pollen from plants in the field and from dried specimens in large herbarium collections. A card catalog accompanying the collection is cross-referenced to the slides and contains information on each plant species represented.

Photo: Carlos Jaramillo uses a microscope to study pollen from the Graham collection. (Photo by Marcos Guerra)

Covered by a tough wall, or ‘exine,’ many pollen grains are incredibly resilient, so much so that they show up as fossils in sedimentary rock tens of millions of years old. “It is not unusual to find rich assemblages of fossil pollen and spores in sediments where no other plant fossils—leaves, stems, seeds—exist,” Graham says. Graham, a paleobotanist, uses fossil pollen to reconstruct the vegetative and ecological history of the Americas, with an emphasis on the last 100 million years. “To quickly identify the prehistoric pollen I retrieve from rocks, it was necessary to create this reference collection of known pollen types,” he explains. Some fossil pollen in the collection is 40 to 45 million years old.

A critical bit of information included in the plant descriptions in Graham’s card catalog are the ecological conditions under which each plant grows and its geologic range. This data is essential to understanding the history of the vegetation and environments of the New World, “giving us a picture of how the earth got to this one brief instant of time we are living in right now, and where it may be headed,” Graham says.

Carlos Jaramillo with labeled boxes that hold some 25,000 samples of pollen grains that were mounted on microscope slides by Alan Graham. (Photo by Marcos Guerra)

“This is one of the largest pollen collections in the world, unique in its coverage of North America and Latin America,” says Carlos Jaramillo, a stratigrapher at the Smithsonian Tropical Research Institute. “Soon, we plan to have all of the components of this collection in digital format, to share on the Web with everyone around the world.”

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