Graduate Student Links Dino Eggshells and Ancient Climates

Thursday, December 08 4:34 pm

Shaena Montanari, a graduate student in the Museum’s Richard Gilder Graduate School, has carried out fieldwork in Mongolia’s Gobi Desert. Photo courtesy of Shaena Montanari. Click to enlarge.

Fourth-year Richard Gilder Graduate School (RGGS) doctoral student Shaena Montanari uses her geology training and subtle clues left by dinosaurs to reconstruct the environment of Mongolia’s Gobi Desert as it was 70 million years ago. Based on an innovative approach that takes cues from the geochemistry of dinosaur eggshells, Montanari’s latest findings—that late in the Mesozoic “age of the dinosaurs” the Gobi desert was a much wetter and warmer place than today—were presented this week at a poster session of the American Geophysical Union’s Fall Meeting in San Francisco.

Montanari is a member of the inaugural 2008 RGGS class in comparative biology. In 2006, the American Museum of Natural History became the first museum in the Western Hemisphere with the authority to grant the Ph.D. degree. Montanari, who received her undergraduate degree in geological sciences from the University of North Carolina, is planning to graduate from RGGS next year. Read more »

Museum’s REU Symposium Spotlights Student Summer Biology Research

Monday, August 16 9:02 am

Nearly 80% of interns from the first 10 years of the Museum’s REU program in biology have gone on to graduate school. Of those, 31% are now working in academia, and 25% hold non-faculty research positions. © AMNH/D. Finnin

The gene flow patterns of Amazonian birds, the diversity of bat teeth, mislabeled species at the local market: these were just a few of the topics presented at the 22nd Annual Research Experiences for Undergraduates (REU) biological sciences symposium held in the Museum’s Linder Theater earlier this month.

The symposium marked the conclusion of the 2010 REU program, a National Science Foundation-funded internship that offers college students the opportunity to work side by side with Museum scientists on research projects in the biological or physical sciences. Nearly 80% of interns from the first 10 years of the REU program in biology have gone on to graduate school and, within this group, 31% are now working in academia and 25% hold non-faculty research positions.

“This program is very important, not only because these undergraduates are generating cutting-edge research, but also for me, because it’s how I got started as a professor,” said Museum Curator Mark Siddall of the Division of Invertebrate Zoology, who has overseen the REU biology program since 2001, during opening remarks at the symposium.

This summer’s eight REU projects in biology spanned species, continents, and methodologies.

Isabella Akker, a student at Stanford University who worked with Joel Cracraft, curator-in-charge of the Museum’s Department of Ornithology, spent the summer sequencing and analyzing the DNA of the Blue-Crowned Manakin—a species of bird found in the Amazonian rainforest—that had been sampled from different geographic locations in South America.

Another REU intern, Berenice Villegas of Columbia University, looked into a phenomenon closer to home. Villegas worked with George Amato, director of the Sackler Institute of Comparative Genomics, to conduct a study that examined the mislabeling of endangered species—including turtle, alligator, and fish meat—sold illegally in New York City markets. Using a tool known as DNA barcoding—or analyzing a fragment of a gene to identify a particular species—Villegas found many cases of mislabeling as well as instances of threatened or near-threatened species for sale.

Villegas, an environmental biology major, said that conducting research with Museum scientists was an invaluable experience. “It was one of the best summers I’ve ever had,” she said of participating in the REU program.

Museum scientists were equally enthusiastic about working with young researchers. John Flynn, dean of the Richard Gilder Graduate School at the American Museum of Natural History, emphasized the value of the REU program in unscheduled remarks at the symposium’s conclusion.

“I was incredibly struck by the tenor of conversation and questioning—a testament to your excellent work as an integral part of creating a new generation of scientists,” said Flynn.

For more information about Research Experiences for Undergraduates at the Museum, please visit the Fellowships and Opportunities section on the Richard Gilder Graduate Schoolwebsite.

Dinosaur Demoted: New Fossil Material Re-Defines Azendohsaurus

Wednesday, May 19 10:35 am

A reconstruction of the skull of the new species of Azendohsaurus. Credit: Sterling Nesbitt

Azendohsaurus just shed its dinosaur affiliation, according to a team of researchers that includes the Museum’s John Flynn. But in doing so, it “ends up being a much more fantastic animal than if it simply represented a generic early dinosaur,” says André Wyss, one of the authors of the new paper published in Palaeontology.

A careful new analysis of a 230-million-year-old Azendohsaurus fossil found more than a decade ago in Madagascar, A. madagaskarensis, aligns this animal with a different and very early branch on the archosauromorph reptile evolutionary tree (the group that includes living birds and crocodiles). This means that the plant-eating adaptations of Azendohsaurus, similar to those found in some early dinosaurs, developed independently, and that herbivores were much more common among archosauromorphs than had been previously thought.

“As we found and analyzed more material, it made us realize that this was a much more primitive animal and that the dinosaur-like features were really the product of convergent evolution,” says John Flynn, a paleontologist at the Museum.  “Even though this extraordinary ancient reptile looks similar to some plant-eating dinosaurs in various features of the skull and dentition, it is in fact only distantly related to dinosaurs.”

For more information, see the official press release, the current research article, and the initial article in Science.

John Flynn Elected as AAAS Fellow

Friday, December 18 3:06 pm

John Flynn, Frick Curator of Fossil Mammals and Professor and Dean of the Richard Gilder Graduate School, joins five other American Museum of Natural History colleagues as a Fellow of the American Association for the Advancement of Science (AAAS).

On December 17, it was announced that Dr. Flynn was elected by his peers for “distinguished contributions in vertebrate paleontology, especially carnivore evolution and faunal succession in South America, and for development of the graduate school at the Museum.”

“This honor emphasizes the value of Museum-based research and encyclopedic collections,” says Dr. Flynn. “My research is highly inter-disciplinary, integrating field and laboratory work, spanning many facets of geology and biology.” Dr. Flynn’s research helps resolve interesting questions like the history of the Andes and the pattern body and brain size changes during the evolution of carnivores.

Museum AAAS Fellows elected in pervious years are anthropologist Robert Carneiro, ornithologist Joel Cracraft, paleontologist Michael Novacek, entomologist Jerome Rozen, and physical anthropologist Ian Tattersall.

After Darwin at AMNH: John Flynn

Friday, November 20 3:51 pm

Fossil Hunting Among Volcanoes With Paleontologist John Flynn

This year, scientists at the American Museum of Natural History are celebrating the 200th anniversary of Charles Darwin’s birth and the 1859 publication of On the Origin of Species with a collection of vignettes describing expeditions and ideas with links to Darwin’s seminal work.

It was during a siesta in the woods that Charles Darwin, exploring the Chilean coast more than three years into his voyage on the H.M.S. Beagle, was shaken by one of the strongest earthquakes known to the local inhabitants. On that February day in 1835, Darwin not only witnessed “the most awful spectacle I ever beheld… [with] not one house left habitable,” as he wrote to his sister Caroline, but he also had an epiphany:

The most remarkable effect of this earthquake was the permanent elevation of the land… [which revealed] mussel-shells still adhering to the rocks, ten feet above high-water mark.… At Valparaiso… similar shells are found at the height of 1,300 feet: it is hardly possible to doubt that this great elevation has been effected by successive small uprisings.

Chilecebus, a reconstruction of which is shown above, is one of the fossils that John Flynn and colleagues have uncovered in the Chilean Andes (Illustration by Velizar Simeonovski, courtesy of John J. Flynn)

While sailing across the Atlantic and past Tierra del Fuego, Darwin had been reading Charles Lyell’s Principles of Geology, in which Lyell laid out the case that massive geological change is based on the slow accumulation of minute changes over time. It was through this lens that Darwin observed the volatile, shifting landscapes that partly informed his theory of evolution.

We now know that the active geology of Chile—the earthquakes, volcanoes, and formation of the Andes Mountains themselves—is caused by the squeezing of the Pacific Ocean plate under South America and back into the Earth’s interior. Paleontologist John Flynn and colleagues André Wyss, Reynaldo Charrier, and Darin Croft have traversed this geology over the last 20 years to learn more about both the history of the Andes and the unusual extinct fauna that lived on this former island continent. Mountain uplift drives fossil beds to the surface, weathering exposes fossil teeth and bone, and volcanic debris dates their time frames.

“We were first drawn to Chile because amateur naturalists found whale bones at 6,000 feet in the 1980s,” says Flynn. “Since then, we’ve uncovered a remarkable mammalian menagerie that explains some of the diversity seen today and also helps us understand more of the uplift history of this 5,000-mile-long mountain chain that forms a spine along then entire western edge of South America.” Read more »