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Smithsonian National Museum of Natural History
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Drawing of a fossil preparator's hand excavating a juvenile Compsognathus dinosaur from rock, as the little dinosaur comes to life.

Visitors to FossiLab may see volunteers working on several of these long term projects. Scroll down to read about them all, or click on a project in this list to jump directly to it.

The partially prepared skull of a brontothere Brontothere Skull A field jacket containing Jurassic dinosaur fossils from Zimbabwe Jurassic Dinosaurs from Zimbabwe
Tiny Cretaceous Fossils from Montana excavating Triassic fossils from Arizona Triassic Fossils from Arizona
Microscopic Foraminifera Fossil leaves Fossil Leaves
A seive containing unsorted fossils from Haitian caves. Small Fossils from Haitian Caves A t. rex claw and two plater replicas Making Fossil Replicas
Scientific drawing of a fossil shell Drawing Fossils with Camera Lucida A large fossil in a storage jacket Building Storage Jackets
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Brontothere Skull
 

One of the most impressive views in FossiLab right now is of a set of very large brown teeth emerging from a block of rock that rests on the table in the center of the room. The teeth belonged to a brontothere, a rhinoceros-like relative of horses and tapirs that became extinct about 35 million years ago. We are using an air scribe to remove the rock matrix from the teeth and the surrounding skull.  The skull, shown below on the left, is upside down, so the teeth, which are attached to the upper jaw, are pointing upward.

Thousands of brontothere specimens have been collected in North America and Asia, allowing scientists to document the many ways that brontothere species changed during their 20 million years of evolutionary history. Reconstructions of some of the many species are shown in the historic drawing by Charles R. Knight shown below, right. 

Watch a video that shows our progress removing matrix from the brontothere skull.

 

A volunteer uses an air scribe to chip away the rock matrix covering a brontothere skull.

A volunteer uses an air scribe to chip away the rock matrix covering a brontothere skull found in South Dakota.

Click this photo of a partially prepared brontother skull to watch a video showing how the rock was removed. Drawings of several different species of brontotheres showing the variation in skull and horn size and shape.

Left: The partially prepared brontothere skull. Click to launch a video showing steps in the removal of the rock covering this fossil. Right: Life-like drawings of different species show some of the variation in skull and horn size and shape that evolved in the brontotheres. Click to zoom.

Follow this link to read. Learn why the brontothere is the "oldest" project in FossiLab: Dental Work, Anyone?

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Triassic Fossils from Arizona
 

On recent field expeditions to Petrified Forest National Park in northern Arizona, Museum curator Dr. Anna K. Behrensmeyer collected fossil-rich matrix dating from the Late Triassic Period (about 200 million years ago). The tiny fossils that FossiLab volunteers are excavating from the small blocks of rock are shedding light on the ecosystem that existed there at that time.

More than 350 good-quality specimens have been recovered from the matrix so far. These are mostly small teeth, but we also have discovered the jaw of a small pterosaur (a flying reptile) - likely a new species. Other specimens include archosaurs (ancestors of crocs and birds), early theropod dinosaurs, amphibians, and fish. The search goes on. We hope to find fossil evidence of early mammals.

Because the fossils are so tiny, we use very small tools - visitors may even see us applying tiny bits of glue to broken fossils with a cat whisker!

Excavating tiny fossils with the help of a microscope.

As we search for the tiny fossils and then excavate them from the matrix, a microscope is essential. A camera projects the work onto a TV screen so that visitors can watch.

A fish tooth excavated from the matrix.A curved, pointed theropod dinosaur tooth still embedded in matrix.The serrated tooth from a <em>Revueltosaurus</em> excavated from the matrix.

Three of the many small Triassic teeth from northern Arizona that have been discovered in FossiLab. Left to Right: A fish tooth, a theropod dinosaur tooth still in matrix, a tooth from a Revueltosaurus (a reptile). Click to zoom.

Follow this link to learn more, including why these fossils started their trip to FossiLab on horseback: Tiny Fossils, Big Excitement

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Jurassic Dinosaurs from Zimbabwe
 

Museum curator Dr. Matthew Carrano traveled to Zimbabwe in 2010 to collect fossils from dinosaurs that lived during the Early Jurassic Period, about 200 million years ago. The remains of dozens of Coelophysis (once called Syntarsus), a meat eating theropod, were found jumbled together in a "bonebed" exposed in the wall of a river canyon. Blocks of rock were cut from the canyon wall and shipped to FossiLab, where we are using air scribes, picks and needles to isolate the bones from the matrix. We also are preparing fossils of the larger plant-eating dinosaur Massospondylus that were found near the bonebed.

A field jacket contains a partially prepared block of rock containing many dinosaur bones.

A jumble of bones from the bone bed in a opened field jacket. Click to zoom.

A volunteer uses a pin vise and carbide needle to remove matrix from fossils from the bone bed.

A volunteer uses a pin vise and carbide needle to remove matrix from fossils from the bonebed.

Follow this link to read about the field work in Zimbabwe: Fossil Hunting under the Watchful Eyes of Lions

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Washing and Picking Tiny Vertebrate Fossils from the Late Cretaceous
 

Tiny bones, teeth, and other small animal fossils can provide rich and exciting information about biodiversity (the variety of species living in a place) in ancient ecosystems. During the summer of 2012, curator Dr. Matthew Carrano’s field team traveled to several sites in Montana in search of fossil evidence of the small animals that lived alongside dinosaurs during the Late Cretaceous, 75 million years ago. They and colleagues from Macalester College brought hundreds of pounds of fossil-rich clay matrix back to FossiLab, where visitors often can see us washing the fossils out of the clay. We use a machine constructed from a bicycle wheel and a motor to loosen and rinse away the clay, then examine what's left behind with microscopes in search of the many different kinds of tiny fossils.

Collecting fossil-rich rock matrix in Montana. Click to zoom.

Clockwise from Top Left: Back in FossiLab, the matrix is placed in sieves and suspended in water. Our fossil washing machine, affectionately called "Duncan," slowly and repeatedly dunks the sieves in the buckets of water. The clay matrix dissolves and passes through the holes in the sieves, leaving the tiny fossils behind. Once the sieves are dry, we pick through the mix looking for small bones and teeth among the white shell fragments and other debris. Click photos on left to zoom.

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Foraminifera

Museum Curator Dr. Brian Huber studies fossil foraminifera to answer questions about ancient changes in climate.

Foraminifera are tiny ocean-dwelling single-celled organisms that construct shells. Different species, identified by their unique shapes and by other shell features, inhabit a wide range of ocean environments, from the intertidal zone to the deep sea.  Benthic species live in sediments on the sea floor, while planktonic species live in the upper 300 feet or so of the ocean.  The shells of dead foraminifera accumulate on the sea floor, where there may be tens of thousands of shells per cubic centimeter (about a fifth of a teaspoon).

The fossil record of foraminifera is ancient, going back more than 550 million years. They are valuable indicators of past climate change because their shells are sensitive to changes in environmental conditions. We measure oxygen isotope ratios in fossil shells recovered from ancient sea beds to determine the geologic history of seawater temperature change near the ocean surface and on the ocean floor.

Several FossiLab projects involve picking or sorting 90 million year old foraminifera cored from rock in Tanzania that formed as ocean sediments accumulated during the Cretaceous.

Visit the Fossil Preparation Page to see how FossiLab volunteers use small paint brushes to pick up and move the minute shells.

A magnified image of a 90 million year old fossil shell from Tanzania.

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jumbled shells of many different foraminifera show a variety of species

Fossil foraminifera found in 120 million year old sediments collected from the deep sea floor, and a living species (inset). Click to zoom.

a volunteer uses a microscope to search through sediment for the fossils of tiny foraminifera

Above: A FossiLab volunteer uses a microscope to see the fossils of tiny Cretaceous foraminifera isolated from Tanzanian rock. Left: This high magnification image of a single shell was made with an electron microscope.

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Fossil Leaves
 

Dr. Scott Wing, Curator of Fossil Plants, has collected and studied thousands of fossil plants from Wyoming and South America for his research into the ecological responses to periods of climate change that occurred between about 70 and 40 million years ago. One period of rapid global warming, called the Paleocene-Eocene Thermal Maximum (PETM), provides the closest analog in earth history to current human-induced global warming. 

The leaves sent to FossiLab are still partly covered by rock matrix that must be removed to reveal as much of the fossils as possible. Leaf preparation is complicated by the fact that a block of rock may contain multiple overlapping leaves, only some of which are of scientific interest. To guide our work, the scientists draw hash marks on the rock to tell us which leaves they need to see and which areas of rock (and, at times, other leaf fossils) must be removed. We use a microscope during preparation to help us see the delicate fossils and avoid damaging them with our tools. The block of rock shown below on the left has been marked for preparation. The fossil shown below on the right is completely uncovered and ready for study.

using an air scribe and microscope to prepare leaf fossils

Using an air scribe to remove matrix covering a fossil leaf.

Left: A partly-covered leaf fossil marked for preparation. Right: A fossil that has been completely uncovered. Both leaves were found in Wyoming. Click to zoom.

Read Dr. Wing's Summer 2011 Field Dispatches to Smithsonian Magazine.

Access a classroom activity based on Dr. Wing's work to learn how the PETM fossils help us understand global warming in the past.

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Small Fossils from Haitian Caves
 

In the 1920s, scientists from the Smithsonian collected fossils dating from the Pleistocene from several caves in Haiti. Descriptions of larger fossils, including the bones of extinct ground sloths and birds were published in scientific journals, but huge numbers of bulk-collected small bones, including those of birds, bats and other mammals, reptiles and amphibians, were left unsorted and undescribed.

A circular sieve contains a jumble of small bones and debris.

Volunteers are now cleaning and picking through this material in FossiLab. The top photo on the right shows unsorted bones that have been washed in a sieve. Sorting is done first by bone type (femur, skull, vertebra, etc.) then by animal type (bird, frog, bat, etc.). The many labeled trays of tiny bones, including those shown in the bottom photo, will be stored in our collections, available for study by researchers interested in island ecosystems, evolution and extinction.

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Humdreds of tiny bones have been sorted into boxes.

Click to zoom.

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Making Fossil Replicas
 

From the upper FossiLab window you can look down on a table where we are making replicas of the right foot bones from a Tyrannosaurus rex. These bones were collected by Museum staff in Montana in 2002 (read about the field work here) and were prepared for study by FossiLab volunteers. Now we are making several sets of plaster replicas, called casts.

First, we coat the fossils with silicon rubber to form a mold. The rubber follows every contour, nook and cranny of the bones, allowing the casts to replicate all the surface detail of the fossils. If the shape of a fossil is "simple," the mold is made in two halves. If it is more complex, the mold may be divided into three or more sections. Each section of silicon mold is reinforced with a plaster "mother mold" which helps maintain the proper shape shape. When the mold is completed, the fossil is removed and the inside of the mold is lined with fiberglass-reinforced plaster to form the cast.

We make casts for several reasons:

NMNH scientists frequently go on collecting expeditions to countries that require the return of any fossils found once they have been prepared and initial studies have been completed. Before we return the fossils, we make and retain exact replicas so that scientists here can continue to study them, and visitors can view them.

We make replicas of fossils in our collections that we wish to display but that are too fragile to withstand the vibrations and heat and humidity fluctuations they would experience on exhibit.  Displaying a replica of the rarest and most delicate fossils allows us to show visitors what they look like without endangering the fossils themselves.

Another reason to make casts is that we sometimes exchange replicas with other museums. Trading allows us to assemble more complete collections, making it easier for scientists to compare fossils that are housed in different museums. It also makes it possible for rare fossils to be displayed in many museums at the same time.

A volunteer prepares to fit together two halves of a cast of a T. rex foot bone.

A FossiLab volunteer works with two halves of a T. rex metatarsal bone cast.

T. rex claw and two casts.

A Tyrannosaurus rex claw and two plaster replicas. Click to zoom.

Several steps in the molding and casting of a fossil whale jaw bone are shown below.
The fossil lower jaw of a Pleistocene Grey whale is set in clay to mark the seam line in ghe mold.The fossil is coated in blue-green silicon rubber.

Left: The fossil lower jaw of a Pleistocene Grey whale found off the coast of Georgia is set in clay to mark the seam line in the mold. Right: The fossil is coated in blue-green silicon rubber to form the first half of the mold.

The two halves of the mold are lined with plaster and fiberglass cloth.The completed cast.

Left: The two halves of the mold are lined with plaster and fiberglass cloth. Right: The completed cast.

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Drawing Fossils with Camera Lucida
 

Scientists include high quality photographs of fossils in the research papers they publish about their discoveries. This allows others to study them and decide if they agree with the scientist's interpretations. Sometimes, if critical features of a fossil are hard to see in photos, a scientific illustrator will be asked to create precise drawings of the fossil. The drawings make the photos easier to interpret by highlighting the important features.

Artists volunteering in FossiLab use a microscope with a camera lucida attachment to make scientific illustrations of small fossils for Museum scientists. With this setup, the artist simultaneously sees a magnified image of the fossil and an image of his or her drawing. The effect is that the artist can "trace" the outlines of the fossil and any critical features, creating drawings that retain very accurate proportions.

Visit the Paleo Art website to learn more about scientific illustration techniques.

A volunteer uses a microscope with a mirror attachment to make precise drawings of small fossils.

A volunteer artist draws a small fossil while looking through a microscope. An arrow points to the round mirror of the camera lucida attachment, which reflects an image of the artist's hand, paper, and pencil into one of the microscope's eyepieces.

a small fossil seashell and two drawings of it made with camera lucida Diagram showing how the mirrored camera lucida attachment helps the artist

Above Left. A small fossil shell (shown in a box in the upper left corner) and two large drawings of it made using a microscope with camera lucida attachment. Above Right. A sketch shows how the mirror in the camera lucida attachment allows an artist to see both a magnified image of the the fossil and his or her drawing. Click images to zoom. Art by James Morrison.

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Building Storage Jackets
 

Once excavated from the rock that has supported them for millions of years, the fragile, brittle fossils are susceptible to damage from vibration, gravity and improper handling. To protect them, we build form-fitted storage jackets with a soft inner layer of foam or felt and an outer layer of hard, fiberglass-reinforced plaster. Visitors to the lab can nearly always see storage jackets at some stage of construction. The work takes place in the large sandbox in the center of the room where sand supports the fossils during the early stages of jacket construction.

Visit another Department of Paleobiology website to read more and watch a video about building storage jackets.

A volunteer opens a storage jacket containing a partial baleen whale skull from Aurora, North Carolina.

A stegosaurus plate resting in a opened storage jacket Storage shelving with jacketed and unjacketed fossils

Left: Building a jacket with plaster-soaked fiberglass cloth. Center: A Stegosaurus plate in an open storage jacket. The bolts that hold the two half jackets together are in the lower half jacket. Right: A view of our collections storage area showing many storage jackets as well as some fossils that have not yet been jacketed. Click to zoom.

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