Picturing Science: Museum Scientists and Imaging Technologies

American Museum of Natural History

Scientists at the American Museum of Natural History see a great deal more than most of us do, thanks to a range of sophisticated imaging techniques. Tools such as remote sensors, scanning electron microscopes, CT scanners, and high-powered telescopes allow researchers to detect evolving supernovas, long-buried ancient villages, microscopic hairs on wasp antennae, and much more. All of the images displayed here were taken as part of ongoing research at the Museum. Come see for yourself.

Lorenzo Prendini (Curator, Division of Invertebrate Zoology) identified differences among scorpion species when exposed to ultraviolet light.

Above: Heads

These vividly colored images of scorpions take advantage of chemicals in the hard outer cuticle, which fluoresce when exposed to ultraviolet (UV) light. Museum arachnologist Lorenzo Prendini used UV fluorescence imaging to identify differences among the species shown. The fluorescence of each species depends on the texture of its surface. Some structures, like eyes and hairlike setae, do not fluoresce at all. The variation reflects the habitats and evolution of the 10 species imaged.

Below: Abdomens, underside.

Egyptian Knife
Alex de Voogt (Assistant Curator, Division of Anthropology) saw Arabic letters on an encased blade with the use of a CT scanner.

Museum anthropologist Alex de Voogt wanted to examine the two blades of an Egyptian knife collected in the 1930s. Unfortunately, the sheath covering one of the blades presented problems. Its leather parts had shrunk, making it too tight to remove, and its lead strips were impenetrable to conventional x-rays. However, a more powerful solution was available: computed tomography, which can digitally remove the sheath.

The payoff: a decorative pattern of Arabic letters is now visible on the blade.

Armadillo Lizard
Edward Stanley (Graduate, Ph.D.-Degree, Richard Gilder Graduate School) revealed hidden patterns of armor in lizards with the use of a CT scanner.

The Latin name for the armadillo lizard—Ouroborus— means “tail-biter,” and it’s no wonder. When this lizard is frightened, it rolls into a ball and hangs onto its tail, like the mythical dragon of the same name. By doing this, the lizard protects its soft belly, exposing only its back—which turns out to be heavily armored.

Edward Stanley, a doctoral graduate in comparative biology of the Museum's Richard Gilder Graduate School, uses CT scanning to view the lizard’s “osteoderms”—its bony plates of armor. The data help link the patterns of armor in related lizard species with their evolutionary history.

A Shark Braincase
John G. Maisey (Curator, Division of Paleontology) observed the calcified cartilage in a shark's skeleton with a CT scanner.

Broadnose sevengill shark
Notorynchus cepedianus

Sharks do not have bones like we do. Instead, they have a skeleton of cartilage hardened by calcium. Employing a CT scanner, Museum paleontologist John Maisey can observe how calcified tissue builds up to form the braincase of a modern shark. Tiny, dense tiles of calcium minerals line the cartilage in order to stiffen it. These tiles are shown in gold in the large image, generated using 3-D density modeling software. Maisey uses this information to compare braincases of modern and ancient sharks.

Cichlid, Ponyfish and Mackerel
John S. Sparks (Curator, Division of Vertebrate Zoology) observed the anatomical differences between fishes through clearing and staining.

At times, art and science converge, as you can see in these glorious images. They’re photos of whole fish, with skin and innards intact. Museum ichthyologist John Sparks treated the fish with a calibrated series of chemical dyes. Red dye tints bones, blue dye clings to cartilage, and enzymes “clear” tissues rendering them transparent.

Next comes the pure science: Sparks uses the image of the fish, along with DNA analysis and other techniques, to study the differences among species. In these images, he is able to observe the cichlid’s unique hearing structures and the ponyfish’s bioluminescent chin. An added treat: a just-consumed fish lies in the mackerel’s stomach.

Tibetan Figures
Judith Levinson and Karl Knauer (Conservators) determined the condition of cultural objects through x-ray imaging.

When you look at artifacts like these Tibetan figures, you probably cannot guess their condition or how they were made. But this is important information for Museum conservators Judith Levinson and Karl Knauer, who are responsible for their care. To investigate, they used x-rays.

In the bronze figure, they found that the hollow body is made from sheet metal, while the hands and feet are solid-cast. As to the wood figure, the x-ray revealed previous repairs – note the nails and screw. It also revealed small objects, called consecration items, placed in a cavity within the body.

Bacteria in Leeches
Mark Siddall and Susan Perkins (Microbiologists) discovered symbiotic bacteria in blood-feeding leeches.

Tiny bacteria make their home within leeches, providing their hosts with essential nutrients. Museum microbiologists Mark Siddall and Susan Perkins use a genetic technique called FISH to uncover this relationship.

They begin by adding DNA to the leech tissue—DNA that is special in two ways. It matches bacterial DNA, so it attaches to the bacteria in the leech tissue. And it has a fluorescent DNA molecule added to it. When the leech tissue is subjected to green light, it causes the bacteria inside to glow orange. Other images show similarly treated juvenile leech tissue glowing, proving that parent leeches pass their bacteria to their offspring.

Views of a Galaxy
Michael M. Shara (Astrophysicist) surveyed a galaxy similar to ours with the Hubble Space Telescope. This dazzling picture actually pieces together 100 images of the galaxy Messier 101, which is 10 million light years away. Our own Milky Way galaxy would look very much like this if seen from a similar distance. The images were captured by a camera on the Hubble Space Telescope as it orbits Earth. As part of their observations, Museum astrophysicist Michael Shara and his team are pinpointing the brightest, hottest stars in this galaxy, called “Wolf-Rayet” stars. They hope to confirm that these highly luminous bodies give rise to supernovas, as predicted by stellar evolution theory.
True Bugs
Randall T. Schuh (Entomologist) found distinctive details of bugs using SEM (scanning electron microscopy).

Many insects are called bugs—but scientifically, only those in the suborder Heteroptera are true bugs. There are about 40,000 species of these bugs, and classifying them is a huge task. Museum entomologist Randall Schuh has made this easier by using high-resolution digital imaging. In addition, the SEM allowed him to view distinguishing features of the bug, like the genitalia seen at right in images of greater and greater magnification.

Denton S. Ebel (Meteoriticist) understood the formation of meteorites with electron microprobe.

Meteorites—rocks that fall to Earth from space—date back to the time when our solar system was forming, about 4.5 billion years ago. By studying meteorites, we can get hints about how our planets began.

To do this, Museum meteoriticist Denton Ebel uses an electron microprobe to excite the atoms on the surfaces of meteorite samples. This produces data that reveal a sample’s mineral composition. Shown at right are four such samples: three “chondrules”—glassy spheres found in many meteorites—and one calcium-aluminum-rich inclusion, a type of rock that is the oldest material to have formed in our solar system.

Extinct Primate's Skull
John Flynn (Paleontologist) observed aspects of an extinct primate’s skull with a CT scanner.

The two-inch (five-centimeter) long fossil skull of the 20-million-year-old Chilecebus (“Chilean monkey”) is the only one of its kind ever discovered. When Museum paleontologist John Flynn, with research associates Xijun Ni and Andre Wyss, investigated its internal structure, cutting open the skull wasn’t an option. Instead they used a high-resolution CT scanner to peer inside. One finding was the shape of the head’s semicircular canals, highlighted here in blue. These structures help control balance, and they affect how animals walk. Another discovery—the extremely small brain size—proves that the monkeys living today in Central and South America evolved large brains after their ancestors migrated from Africa.

Credits: Story

Picturing Science: Museum Scientists and Imaging Technologies was made possible by the generosity of the Arthur Ross Foundation.

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The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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