“Nothing makes sense,” explains Martin Nweeia, a practicing New England dentist and member of the Smithsonian’s Department of Vertebrate Zoology and the Harvard School of Dental Medicine. For one, narwhals have no teeth. “They eat large fish, yet swallow them whole. If you look in its mouth there’s nothing.  There are absolutely no teeth.”

Image right: The mouth of a narwhal has no teeth. (Photo by Martin Nweeia)

Incredibly, the narwhal’s only visible tooth is outside of its mouth. Its tusk, in fact, is a giant canine tooth—that can grow as long as 9 feet—with a distinct left-hand spiral, covered in a tissue called cementum, normally only found around the base of a tooth lodged in bone.

Nweeia and a team of dentists and zoologists from the Smithsonian’s National Museum of Natural History, Harvard and other research organizations recently took a very close look at the dentition of the narwhal’s mouth. They studied more than 130 skulls in museum collections and 21 skulls of narwhals killed by native hunters in Canada. In a new paper published in The Anatomical Record, the team determined:

• The long spiral tusk of the male narwhal is one of a pair of canine teeth positioned horizontally in the animal’s skull. They determined it was a canine and not an incisor because the tusk originates in the narwhal’s maxillary bone, where canine teeth in mammals originate. This is the first study to confirm the tusk as a canine tooth. In most mammals, canines are vertical in the mouth and are used for holding food or as weapons.

• It is the left tooth of the pair that grows into a long tusk that erupts through the narwhal’s upper lip. The right canine tooth is also a tusk but it remains embedded in the narwhal’s skull unerrupted. Only occasionally do both tusks erupt. Female narwhals have two embedded tusks that erupt only very rarely.

Image left: A rare double-tusked narwhal in the collection of the National Museum of Natural History is examined by Martin Nweeia, left, and Charles Potter, collections manager, Smithsonian Marine Mammal Program. (Photo by Joseph Meehan)

• A second pair of tiny teeth is located in open tooth sockets in the narwhal’s snout alongside the tusks. These teeth are vestigial, meaning they have no function. Close inspection across many specimens reveal extreme variation in location, morphology and histology (tissue structure) of these teeth, all indications they “are following a pattern consistent with evolutionary obsolescence,” the scientists write.

“It is striking when you think that this animal decided to take all of its tooth-producing energy and put it into one thing [a tusk] that sticks out nine feet into the ocean. With the amount of energy that it takes to produce that one tusk it could easily have 30 to 40 teeth in its mouth doing other things,” Nweeia explains. “Evolutionary-wise something is saying don’t do this, instead it is better to grow this extraordinary tusk.” A pretty compelling reason must be behind such a decision.”

Image right: An array of vestigial teeth collected from narwhals. (Photo by Joseph Meehan)

Did the narwhal once have teeth oriented vertically in its mouth as do other mammals? “One might assume this animal once had more teeth positioned vertically in the mouth, but there is no evolutionary evidence to say that would be true,” Nweeia explains. “With whales the evolutionary pieces of the puzzle are scant and I prefer to leave speculation out of the equation.”

There are many kinds of curious expressions of teeth in whales, narwhals being the most extraordinary, Nweeia says. “The strap-toothed whale, for example, has two teeth that wrap over its upper jaw preventing the animal from opening its mouth.”

Image left: The dissection team at the Osteo-Prep Lab of the Smithsonian’s National Museum of Natural History begins dissection on a male narwhal specimen. From left, James Mead, curator emeritus, Museum of Natural History; Ted Cranford, San Diego State University; and Martin Nweeia. (Photo by Chip Clark, Smithsonian Institution)

“The whole thing that is great about the teeth of the narwhal is that nothing makes sense,” Nweeia adds. “The tusks are an extreme example of dental asymmetry. They exhibit uncharacteristic dimorphic or sexual expressions since females do not exhibit erupted tusks as commonly as males. Also, the tusk has a straight axis and a spiraled morphology.  Conventional mechanisms of evolution do not help explain these expressions of teeth.”–John Barrat

Article link: “Vestigial Tooth Anatomy and Tusk Nomenclature for Monodon monoceros,” The Anatomical Record, April 2012. Authored by Martin T. Nweeia, Frederick C. Eichmiller, Peter V. Hauschka, Ethan Tyler, James G. Mead, Charles W. Potter, David P. Angnatsiak, Pierre R. Richard, Jack R. Orr, and Sandie R. Black.

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Discovered with a nearly complete skeleton, the feathers retained enough microscopic structure to allow the scientists to confirm the classification of the bird, known by its scientific name Apteribis sp, as a close relative of the American white ibis and scarlet ibis. DNA analysis confirmed this classification.

Image left: Skull (top) and (below) detail of feathers adhering to the cranium of Apteribis sp. from Lanai, Hawaii Islands (Photo courtesy Carla Dove)

Remarkably, the feathers also retained enough pigmentation to allow Dove and Olson to determine the bird had been brown-black to ivory-beige/light brown in color. Before now, any reconstruction of the appearance of a prehistorically extinct Hawaiian bird had been only speculation.

Image right: This scanning electron photomicrograph shows the prongs on the downy barbules of an Apteribis sp. feather. (Photo courtesy Carla Dove)

Apteribis sp. is one of only two species of ibises, both now extinct, known to be flightless. Its skeleton differs so much from its mainland ancestors that the bird’s relationship to other ibises could only be determined through the study of its feathers and DNA analysis, Olson says.

The find is highly unusual because “feathers do not preserve well and often decay before a bird is fossilized,” Dove says. “These weren’t fossil imprints in a rock, but feathers and bones we could actually pick up.”

Exceptional geologic circumstances led to the preservation of the feathers inside a lava cave on the Hawaiian Island of Lanai. The floor of the cave was partially covered in a deep layer of flaky gypsum crystals, which, for hundreds of years absorbed humidity in the cave and created an arid environment ideal for preservation of the feathers. The crystals were shaken off of the walls and ceiling of the lava tube by seismic tremors.

Image right: American white ibis (Photo by Terry Foote at en.wikipedia); below, scarlet ibis (Photo by Hans Hillewaert). Both of these birds are closely related to the extinct Apteribis sp., which did not fly.

From a taxonomic standpoint feathers are significant because the shape of microscopic barbs on specific areas of a feather have distinct features that taxonomists can use to determine what bird group it belongs to, Dove says.

“The barbs are unique only on the downy, fluffy part at the base of the feather, not at the tip,” Dove says. “These microstructures are similar among orders of birds—pigeons, ducks, songbirds, for example.

Using the extensive collections in the Division of Birds at the National Museum of Natural History, Dove compared the microscopic structures of the ancient feathers (which she describes as “short barbules with these long prongs,”) to those of modern day birds.

Her analysis confirmed that Apteribis sp. is most closely related the New World ibises of the genus Eudocimus, the American white ibis (Eudocimus albus) and scarlet ibis (Eudocimus buber). Apteribis sp. was first described from fossils found on the Hawaiian Islands of Molokai and Maui. It is one of dozens of bird species known to have gone extinct following the arrival of humans on the Hawaiian Islands.

“Fossil Feathers from the Hawaiian Flightless Ibis (Apteribis SP.): Plumage Coloration and Systematics of a Prehistorically Extinct Bird,” by Carla Dove and Storrs Olson appeared in the September 2011 issue of the Journal of Paleontology.

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This 53-second video consists of a series of images taken with a Siemens Somotom CT scanner of a mummy at the Department of Anthropology in the Smithsonian’s National Museum of Natural History, Washington, D.C. The individual shown here is a male who died at about 40 years of age; a relatively mature age by ancient Egyptian standards. He is believed to have lived in Lower Egypt sometime between the 25-26th Greco-Roman periods, which is between 600 B.C. and about 150 A.D., or roughly 2,500 to 1,900 years ago.

When this mummy was transferred to the Smithsonian from the Wistar Institute in Philadelphia in the late 1950s, it was partially unwrapped, and very little was known about its history or the individual inside.

Years later, using 2-dimensional and 3-dimensional CT scans, Natural History Museum anthropologists found that the brain and major organs were removed and rolls of linen filled out the abdominal cavity. This mummification method is evidence of superior embalming, indicating a person of higher status.

The CT scanner uses x-rays to produce a series of 2-dimensional image slices which, for this video, were processed and converted into a 3D model. Two different CT filters were used to extract and digitize the physical properties of the mummy—a bone filter to extract images of the mummy’s bones and a second filter that imaged the mummy’s soft tissues, both inside and out.

After the flesh and bone was digitally extracted, the data were imported into a computer program called 3D Studio Max, where virtual cameras were set up, an animation path was assigned and an animated clipping plane was set up to visually “grow” the mummy.

This and other CT scan images of human and animal mummies will be featured on a Website accompanying “Eternal Life in Ancient Egypt,” an exhibition opening at the Smithsonian’s National Museum of Natural History on Nov. 17, 2011. The exhibition will explore ancient Egyptian life, religious beliefs and examines how the burial practices serve as windows into ancient cultures and reveal how archaeologists and physical anthropologists gain these insights through their research.

This video was made possible by Meg Rivers in the Exhibition Department and Dr. Dave Hunt in the Anthropology Department at the Natural History Museum and Adam Metallo and Vincent Rossi of the Smithsonian’s Digitization Program Office.

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Now, recent work by paleobiologist Nick Pyenson of the Smithsonian’s National Museum of Natural History, has revealed a second, equally valuable resource for information on cetaceans—the record of dead whales and dolphins stranded and washed ashore on beaches around the world.

Image right: The skeleton of a rorqual whale lies in the sand along the shoreline of northern Namibia. (Photo by Lisa Levin, Scripps Institution of Oceanography)

‘Some 30 years ago scientists got serious about the conservation of cetaceans, and began keeping records of strandings,” Pyenson says. Stranding networks were set up around the world and information—such as species type, sex, age, size, cause of death—have been carefully collected, recorded and archived.

By compiling and comparing long-term data from stranding records and visual sighting records, both taken from nearly every ocean basin in the world, Pyenson verified that stranding records “faithfully reflect the number of species and the relative abundance” found in live surveys.

In fact, Pyenson says, the stranding data in many parts of the world “almost always provides better diversity information about existing cetacean communities than the live surveys. A lot of rare species show up in stranding records that never appear in the live surveys,” Pyenson adds.

Image left: The skull of a bottlenose dolphin rests atop shell accumulations on an island of the Colorado River delta, Baja California, Mexico. (Photo by Nicholas Pyenson)

The stranding record also faithfully reflects the structure of cetacean communities. “There is a strong and significant correlation in relative abundance of species at nearly all taxonomic levels in both the live data and the stranding data.”

Pyenson’s study, which he refers to as “spreadsheet taphonomy,” is the first time the cetacean stranding record has been verified as a viable reflection of the living community, across the globe. The live sighting and stranding data used in his research came from the coastlines of Australia, the Galapagos Islands (Ecuador), Greece and the Greek Archipelago, Ireland, The Netherlands, New Zealand and the United States. Pyenson based his approach on a study published last year, in the journal Paleobiology, which examined the stranding record of California, Oregon and Washington State.

Pyenson’s current paper, which appeared in a recent edition of the Proceedings of The Royal Society B, imply that other scientists seeking taxonomic data on living cetaceans for a specific region “should consult the archived stranding data rather than conduct a survey,” Pyenson says. “The best results come from bodies of water adjacent to long coastlines where data have been collected for more than 10 years.”

“The results of this live-dead comparison show that key aspects of cetacean community diversity is actually preserved in the stranding record, which is important if you want some baseline for understanding their diversity in the fossil record,” Pyenson adds. Strandings have more in common with natural traps, like the Rancho La Brea tar pits, which provide snapshots of diversity in restricted areas, than they do with live surveys. It is possible, Pyenson says, that fossils from certain geologic strata may even hold clues to the structure and abundance of extinct cetacean communities.

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Image right: This aerial image of two kites in the desert of Syria shows the long V-shaped structure into which gazelles were herded by hunters. The animals ended up inside the circular stone enclosure at the end of the V, where they were killed. The name “kites” comes from the appearance of these structures when viewed from the air. Click to enlarge. (Image: Google Maps)

The mass of bones is located near a number of ancient human-built stonewall enclosures known as “kites,” structures into which animals were driven and killed by hunters. Many kites dot the landscape in the Syrian Desert along what is presumed to be the former migration route of the gazelles. Use of these kites was common and widespread in the region from 4,000 to 1,000 B.C. Until now, how kites were used and which animals they were used to capture was open to some speculation, as no animal remains had been found in direct association with the kites.

Image left: A group of Persian gazelles in the Hamburg Zoo, Germany.

The bone deposit consists almost entirely of the lower, non-meaty feet of the gazelles, indicating the animals were systematically skinned and dismembered at the site and the meatier sections were transported elsewhere for distribution. The shallowness and compactness of the bone deposit indicates a single butchery episode, the scientists say.

Use of kites for the mass harvesting of gazelles and other desert ungulates arose well after people in the region began keeping domestic livestock for food, the scientists point out. Gazelle meat was only a supplementary source of protein for the hunters during this time. “This indiscriminate hunting strategy sets it apart from the more targeted and sustainable practices of earlier periods, when wild animals were the major or sole source of animal protein,” the scientists write.

Image right: This rock art image from the Jamma Plateau shows a gazelle inside a kite with a hunter blocking its escape.

Rock art discovered near some kites depict these stone traps being used to hunt Persian gazelles. Such graphics found near the Tell Kuran deposit “indicates that the capture of these animals played an important social role that was imbued with religious overtones,” the scientists write. “The hunting and processing of these animals (and possibly other game, such as onager) required the coordination of numerous people responsible for building and maintaining kites, driving and killing animals, and transporting them back to habitations sites like Tell Kuran for butchery.”

“Unlike earlier hunting practices that targeting individual animals, we propose that mass-kill strategies using kites resulted in the decimation of whole breeding populations of gazelle, preventing a rebound of their numbers,” Zeder says.  “More importantly, these practices would have disrupted the overall migratory pattern of these animals leading to the fragmentation of their large migratory populations” the scientists write. In essence, the use of the kites some 5,000 years ago marked the beginning of the end for the Persian gazelle. Modern firearms and habitat loss in the 20^th century represents a final coup de grâce for these animals.

The article “Role of mass-kill hunting strategies in the extirpation of Persian gazelles (Gazella subgutturosa) in the northern Levant,” is available online at www.pnas.org. –John Barrat

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Paleontologists at Yale University and the Smithsonian Institution have discovered that Xenicibis, a member of the ibis family that lived about ten thousand years ago and was found only in Jamaica, most likely used its specialized wings like a flail, swinging its upper arm and striking its enemies with its thick hand bones.

Image right: Skeletal reconstruction of Xenicibis xympithecus based on a specimen at the Smithsonian’s National Museum of Natural History and fossils from the Red Hills Fissure cave deposits, Saint Andrews Parish, Jamaica. (Illustration by Nicholas Longrich, Yale University)

“No animal has ever evolved anything quite like this,” said Nicholas Longrich of Yale, who led the research. “We don’t know of any other species that uses its body like a flail. It’s the most specialized weaponry of any bird I’ve ever seen.”  Storrs Olson, ornithologist at the Smithsonian’s National Museum of Natural History, and Longrich are co-authors of a paper on this research published in the Proceedings of the Royal Society B.

As part of the new study, the researchers analyzed a number of recently discovered partial skeletons of Xenicibis and found that the wings were drastically different from anything they’d seen before. “When I first saw it, I assumed it was some sort of deformity,” Longrich said. “No one could believe it was actually that bizarre.”

Image left: The prehistoric Xenicibis used its wings like two clubs hinged at the wrist joint in order to swing at and attack one another. (Illustration by Nicholas Longrich, Yale University)

The bird, which was the size of a large chicken, is anatomically similar to other members of the ibis family except for its wings, which include thick, curved hand bones unlike those of any other known bird. Xenicibis also had a much larger breastbone and longer wings than most flightless birds. “That was our first clue that the wings were still being used for something,” Longrich said.

While other birds are known to punch or hammer one another with their wings, Xenicibis is the only known animal to have used its hands, hinged at the wrist joint, like two baseball bats to swing at and strike its opponents. Although modern day ibises do not strike one another in this fashion, they are very territorial, with mates often fighting other pairs over nesting and feeding rights.

It’s also possible that the birds used their club-like wings to defend themselves against other species that might have preyed on the birds’ eggs or young. Xenicibis is unusual in that it became flightless even in the midst of a number of predators, including the Jamaican yellow boa, a small extinct monkey and over a dozen birds of prey.

The team found that two of the wing bones in the collection showed evidence of combat, including a fractured hand bone and a centimeter-thick upper arm bone that was broken in half. The damage is proof of the extreme force the birds were able to wield with their specialized wings, Longrich said. –Suzanne Taylor Muzzin, Yale University Office of Public Affairs and Communications

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Image right: Neandertal teeth from Shanidar Cave.

“Neandertals are often portrayed as very backwards or primitive,” said Amanda Henry, lead researcher and a post-doctoral researcher at GW. “Now we are beginning to understand that they had some quite advanced technologies and behaviors.”

Henry made this discovery together with Alison Brooks, professor of anthropology and international affairs at GW, and Dolores Piperno, a senior scientist and curator of archaeobotany and South American archaeology at the Smithsonian National Museum of Natural History, Washington D.C., and the Smithsonian Tropical Research Institute, Panama.

Image left: Neandertal teeth from Spy cave.

The discovery of starch granules in the calculus on Neandertal teeth provides direct evidence that they made sophisticated, thoughtful food choices and ate more nutrient-rich plants, for example date palms, legumes and grains such as barley. Until now, anthropologists have hypothesized that Neandertals were outlived by early modern humans due in part to the former’s primitive, deficient diet, with some scientists arguing Neandertals’ diets were specialized for meat-eating. As such, during major climate swings Neandertals could be outcompeted by early humans who incorporated diverse plant foods available in the local environment into their diets.

Henry, Brooks and Piperno’s discovery suggests otherwise. The researchers discovered starch granules in dental calculus, which forms when plaque buildup hardens, on the fossilized teeth of Neandertal skeletons excavated from Shanidar Cave in Iraq and Spy Cave in Belgium. Starch granules are abundant in most human plant foods, but were not known to survive on fossil teeth this old until this study. The researchers’ findings indicate that Neandertals’ diets were more similar to those of early humans than originally thought. The researchers also determined from alterations they observed in the starch granules that Neandertals prepared and cooked starch-rich foods to make them taste better and easier to digest.

Image right: Microscope views of vegetable starch grains taken from Neandertal teeth.

“Neandertals and early humans did not visit the dentist,” Brooks says. “Therefore, the calculus or tartar remained on their teeth, preserving tiny clues to the previously unknown plant portion of their diets.”

The article, “Microfossils in calculus demonstrate consumption of plants and cooked foods in Neandertal diets,” will appear in a forthcoming issue of the Proceedings of the National Academy of Sciences and will be published online Dec. 27. PNAS is a weekly journal that publishes research that spans the biological, physical, and social sciences.–Emily Cain, George Washington University

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Image right and below: Removing Lexington’s skeleton from a crate at the International Museum of the Horse. Below: Lexington on exhibition in Lexington. (Photos courtesy Bill Cooke)

“More than any human, Lexington established this town as the site of thoroughbred breeding,” says Bill Cooke, director of the International Museum of the Horse, a Smithsonian Affiliate museum. “With the 2010 World Equestrian Games being held here for the first time outside Europe, it gave us another reason to pursue this loan.”

When Cooke first contacted the Smithsonian requesting the loan of Lexington’s skeleton, the horse was on exhibit in the National Museum of Natural History’s Osteology Hall as a fine example of Equus caballus. “We couldn’t remove a specimen that occupied such a prominent place in the exhibition,” says Linda Gordon, collection manager in the Division of Mammals at the museum.

In 1999, Lexington traveled across the street to the Smithsonian’s National Museum of American History where he provided context to the story of the first mass-produced stopwatch that split time into fractions of seconds. When that museum closed for renovations in 2006, Lexington was finally available for loan. “His place in the Osteology Hall has been filled with a zebra skeleton, so Lexington’s skeleton was cleared for loan requests,” Gordon says. “This was my first big loan to an Affiliate museum, so the staff of Smithsonian Affiliations was very helpful in nudging me and keeping me on track.”

What appeared to be a simple loan became more challenging as Gordon lined up a conservator, a bracket-making specialist, and a packing and shipping company. “At first, we thought the armature running through Lexington’s spine was damaging the skull,” Gordon explains. “Our experts examined the bones closely and realized that the damage had occurred during the horse’s lifetime. He had had a massive facial infection that resulted in his going blind.”

Once it was determined that Lexington’s skeleton would not be damaged by further display, Gordon’s team cleaned the bones, made minor repairs, and prepared them for travel. “Although the skeleton was mounted a long time ago, they did a really good job. The skull is perfectly balanced on the best point for the armature. It’s a lost art — no one does this today,” Gorgon says.

Image left: “Portrait of Lexington” by Thomas J. Scott, 1888, oil on canvas mounted on fiberboard, Smithsonian American Art Museum Gift of Mr. and Mrs. David K. Anderson, Martha Jackson Memorial Collection

Other museums in Lexington, Ky., also are participating in a celebration of the horse. The Headley-Whitney Museum, also a Smithsonian Affiliate, has borrowed a portrait of Lexington, painted by Pennsylvania artist Thomas J. Scott, from the Smithsonian American Art Museum. “Lexington was painted from life from the Civil War period on,” said Eleanor Harvey, chief curator at the American Art Museum. “Our painting is unusual in that it shows him in his prime, when he was the horse of the 19th century. It is a beautifully unified studio portrait.” Harvey said that while the loan process is the same for all museums, “we go the extra mile if we can do a loan to a Smithsonian Affiliate. We are happy to loan our gems if it helps people discover the jewels in their own backyards.”–Cara Seitchek

Follow this link to learn more about Smithsonian Affiliations.

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