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Archive for the ‘This week in paleo’ Category.

Werning co-authors paper on growth in Parasaurolophus

Baby Parasaurolophus reconstruction by Tyler Keillor

Artist's restoration of the head of "Joe," the baby Parasaurolophus. Illustration by Tyler Keillor.

Recent Ph.D. grad Sarah Werning, now in a postdoctoral position at the State University of New York at Stony Brook, was a major contributor to a paper released today on ontogeny in Parasaurolophus, a Cretaceous hadrosaurid dinosaur notable for the hollow, bony tube on its skull. The study centers around a remarkable skeleton of a baby Parasaurolophus (nicknamed "Joe") discovered in 2009 by Kevin Terris, a student at The Webb Schools in Claremont, California, in exposures of the 75-million-year-old Kaiparowits Formation, Grand Staircase-Escalante National Monument, Utah. The Webb has been taking students to Grand Staircase-Escalante to prospect for and collect dinosaur bones for several years.

Werning did histologic studies of the six-foot-long specimen and found that the animal was not even one-year old when it died. Sarah reported that "Dinosaurs have yearly growth rings in their bone tissue, like trees. But we didn't see even one ring. That means it grew to a quarter of adult size [25 feet] in less than a year."

Three-dimensional scans of the entire skeleton were made and are freely accessible online. See the paper, along with the 3D scans, in the open-access journal PeerJ. Co-authors on the paper are Andrew Farke of the Raymond M. Alf Museum of Paleontology, Claremont, California, and Webb students Derek Chok, Annisa Herrero, and Brandon Scolieri.

Read more about "Joe" and see photos and video relating to the recovery, preparation, and study of the specimen.

Read more about Sarah's research on her website.

Cycads: Not the “living fossils” that we thought

cycad cones close-upPalm-like cycads have been around since the last dinosaurs munched on them 65.5 million years ago, but those that we see today are really only a few million years old, according to a new study by an international team of scientists.

“Cycads are poster-child living fossils, yet the living species are really young,” reports UCMP Director and Professor of Integrative Biology Charles Marshall, co-author of the study appearing online October 20 (in advance of publication) in Science. “So, while the group as a whole are living fossils, the species themselves are not.”

Cycads are endangered cone-bearing plants that have survived in tropical and subtropical pockets to the present. The UC Botanical Garden hosts a nationally recognized collection of cycads, many of which were rescued from plant smugglers.

Molecular evidence was used to show that the surviving cycad species are actually not relics of the dinosaur era, but the result of an evolutionary explosion among cycads that began about 12 million years ago.

“All the cycad species we examined diverged from their nearest relatives in a really narrow window of geologic time, well after the dinosaurs became extinct” said co-author Charles Marshall, director of the University of California Museum of Paleontology and a UC Berkeley professor of integrative biology. “This was a global event, and then the diversification essentially stopped in the last couple of million years. There is no other group of plants that has this remarkable pattern of diversification.”

cycads

“We can now say that living cycad species are not ancient or leftovers from dinosaur times,” said Nathalie Nagalingum, a research scientist at the Royal Botanic Garden in Sydney, Australia, who led the study while a post-doctoral fellow in Marshall’s laboratory at Harvard University and subsequently UC Berkeley. “They evolved independently of dinosaurs only 12 million years ago. The recent radiation of cycads radically changes our view of these emblematic living fossils.”

Nagalingum, Marshall and colleagues studied all 11 groups of cycad and two-thirds of the world’s 300 species, developing a molecular clock that told them how recently living cycads diverged from one another. If they had truly dated from the dinosaur era, the times of divergence between the living species would have dated back to their heyday in the Jurassic, which began 200 million years ago. Instead, they found the living species originated within the last 12 million years or so.

“It was amazing that all the cycad groups across the globe in Australia, Africa, Southeast Asia and Central America began to diversify at the same time,” Nagalingum said. “This indicated that a global trigger may have been responsible. It seems that the trigger was a change in the climate, that is, when global cooling began and when the world started having more distinct seasons. Cycads are very slow-growing plants so it’s hard to predict whether cycads can survive, now that climate change is occurring at a much faster rate,” she said.

Nagalingum and Marshall's coauthors include Tiago Quental, a former UC Berkeley post-doc now at the Universidade Estadual de São Paulo, Brazil; Hardeep Rai of Utah State University; Damon Little of the New York Botanical Garden; and Sarah Mathews of Harvard University’s Arnold Arboretum.

See the abstract of the study, Recent Synchronous Radiaton of a Living Fossil on the Science website.

125,000 years of geologic change in SF Bay, not much change in the microfauna

San Francisco Bay. Image courtesy of USGS.

San Francisco Bay has had a dynamic and complex history over the past million years as sea level rose and fell at least four times with alternating warming periods and glaciations. About 13,000 years ago, the first group of humans arriving in the area would have walked through a valley with a river flowing nearly 48 km out toward the ocean.  The current bay formed only about 6,000 years ago.

In a recent paper published by Quaternary Research, Amy Lesen, former PhD student in UCMP and currently Chair of Biology at Dillard University in New Orleans, and Professor of the Graduate School Jere Lipps, compare the foraminifera present in the San Francisco Bay today with what was present 125,000 years ago. According to their results, not much has changed in the species that are present. However, the human introduction of a Japanese invasive species, Trochamminia hadai, in 1983 dominated the native foram species and produced more change in the microfaunal assemblage within the last 30 years than within the time it has taken to form the bay. This work sponsored by the UCMP serves as an example of how human actions can have a more severe impact within a small amount of time than the natural changes that take over several millennia.

SEM images of foraminifera a. Ammonia beccarii and b. Buliminella elegantissima. Images courtesy of Quaternary Research.

Congratulations to Mark Terry

Mark TerryMark Terry, a long time Teacher Advisor to UCMP, is the recipient of the 2011 Evolution Education Award, an annual award sponsored by AIBS and BSCS.

Mark is a high school Biology teacher at The Northwest School in Seattle. I first met Mark in 2000 when he sent an email inquiring about a conference that we were hosting — The National Conference on the Teaching of Evolution. The conference served to bring together members from professional societies to examine what their roles might be in supporting the teaching of evolution. Mark felt that he could gain much from such a meeting of the minds, but we probably gained more from Mark than the other way around. It became clear to us that there were a core number of teachers who were doing an excellent job of teaching evolution and that bringing them together to develop a resource for others would be an excellent contribution to the science education community. This served to initiate conversations that eventually led to a successful NSF proposal and the development of the Understanding Evolution (UE) website.

Mark officially became part of the UCMP community by serving as a Teacher Advisor to the UE project in 2002. As such, he attended meetings with other advisors, advised on the basic content of the site, contributed successful activities, and reviewed materials as they became available. Though there was a small honorarium involved, Mark gave of himself way beyond what was asked of him. Knowing how effective he was in this advisory role, it was not long before he was invited to also serve as an advisor to two of our other related projects: The Paleontology Portal and Understanding Science.

So what makes him special? First, it is that passion for teaching. I visited his school and watching him “in action” was extraordinary. He has the confidence that comes with depth of knowledge and experience, the flexibility that comes from years in the classroom, and a wonderful ability to urge his students to find out the answers on their own in a way that inspires their own confidence that they will be successful in doing so … eventually! With an avid interest in history, Mark also integrates the history of science into his teaching so that his students can see how science itself evolves with new data and new evidence, thus giving them a better understanding of how science works. And his classroom is full of skulls and other skeletal parts that support a comparative anatomy approach to studying ancestry and detailed observations through the biological illustration that he encourages.

Second, it is his passion for science. Mark literally gobbles up the paleo and evo literature, so he is on top of current research and brings his excitement of new discoveries into the classroom. That same excitement is extended into the field as he takes his students on paleo field trips to John Day Fossil Beds National Monument each year and he also serves as a field assistant to his daughter, Becca Terry, a graduate from his school and now a Ph.D. in paleontology. In fact, I have lost track of the number of Mark’s students who have gone on to receive degrees in paleo, evolutionary biology, and related fields.

But Mark contributes to the evolution education community beyond his own teaching and his work with the UE project, so there is a third component that deserves recognition. Because of his depth of knowledge, he is often asked to give talks to other teachers on the importance of teaching evolution and effective strategies for doing so. The science research community also benefits from Mark’s expertise, in particular through his work as past Chair of the Education Committee for the Society of Vertebrate Paleontology (SVP). In that role, he and I initiated what have now become an annual teacher workshop and a Round Table evolution discussion for SVP members that are incorporated into their meeting each year. This provides an opportunity to bring resources to teachers wherever the meeting is being held (e.g., 2010 Pittsburgh, 2009 Bristol, England, 2008 Cleveland, 2007 Austin) and to update the members on new resources, new strategies, and (regretfully) new challenges. Being right down the street from the Discovery Institute, Mark stays on top of activities and framing used by anti-evolutionists and keeps SVP members aware of these efforts.

Mark works in a small private school in Seattle, but his impact in evolution education is far greater and his impact on his students means that his legacy also continues through them. It has been such a joy and privilege to work with Mark. I learn from him and I am inspired by him. He is most deserving of the recognition that comes with this award.

The Opportunistic T. rex

Looks like the tyrant lizard wasn't so scary after all.

UCMP's Mark Goodwin and Jack Horner, curator of paleontology at the Museum of the Rockies, have been working in the late Cretaceous Hell Creek Formation of Eastern Montana for decades, an area famous for its impressive fossil assemblages including fish, mammals, and dinosaurs like Tyrannosaurus rex.

Based on a census of predator and prey found at several of the time intervals represented in the Hell Creek Formation, Goodwin and Horner concluded that T. rex was far too abundant to be a lion-like top predator. Top predators are usually one-third or one-fourth as abundant as their prey due to their larger energetic requirements. Opportunistic carnivores like hyenas, however, can number twice that of top predators. With the results of their census and no evidence that T. rex was an extra picky or capable hunter, the scientists suggest it likely subsisted on both live and dead animals, exploiting a variety of food sources like the hyena.

Check out the press release to find out more!

National Fossil Day at UCMP

Yesterday was the first ever National Fossil Day and UCMP pulled out all the stops!

Come check out the new online exhibit, Fossils in our parklands: Examples of UCMP service and stewardship, featuring fossils in UCMP's collection from national and state parks in California, Nevada, Oregon, and Montana. The museum played a pivotal role in the creation of some of the featured parks and we're happy to highlight our shared histories.

Additionally, the 2011 UCMP Fossil Treasures Calendar is now available for purchase! Click here to take a peek at the stunning photos included in the calendar and to find out how to purchase it online. If you're in the area, you can drop by in person for a discounted price. Remember, proceeds help fund graduate student research in the field of paleontology.

Finally, have a look behind the scenes at our in-house celebration...

(Event photos courtesy of Nathalie Nagalingum.)

Global warming and declining mammal diversity: new research in Nature

Pleistocene survivor, the deer mouse.  Photo by Glenn and Martha Vargas © California Academy of Sciences

Pleistocene survivor, the deer mouse. Photo by Glenn and Martha Vargas © California Academy of Sciences

Popular images of Ice Age California tend to feature enormous, extinct mammals like mammoths and saber-toothed cats.  By contrast, new research published in Nature examines populations of small mammals that survived through the end of the Ice Age and how they were affected by the climate change.

The research team of Jessica Blois (formerly at Stanford, now at University of Wisconsin, Madison), Elizabeth Hadly (formerly of UCMP, now at Stanford) and Jenny McGuire (UCMP) studied fossilized woodrat nests collected from Samwell Cave in Northern California.  Woodrats carry scat and regurgitated pellets produced by carnivores back to their nests.  These collections are filled with undigested small mammal bones, making fossilized woodrat nests treasure troves for paleontologists.

Comparing fossil data to modern small mammal populations in the same region revealed a big decrease in diversity during a period of global warming at the end of the Pleistocene Epoch.  There was a decrease in both species richness (number of different species) and evenness (relative dominance of species within a community).  A few species disappeared from the area entirely.  Some species remain in the area but as a much smaller proportion of the overall small mammal community.  And the main species to increase in relative abundance was the deer mouse — an animal that can tolerate a wide variety of habitats and climates.

Research of historic periods of global warming improves our understanding of how modern, man-made global warming will affect life on Earth.  Read more about this research:

Ardi is Breakthrough of the Year

Credit: Jay Matternes © 2005

Credit: Jay Matternes © 2005

Ardipithecus ramidus has been named Science magazine's Breakthrough of the Year. At 4.4 million years old, Ardi is the oldest hominid skeleton. This fall, a series of 11 papers about Ardi and her paleoenvironment were published in Science. UCMP Faculty Curator and Human Evolution Research Center (HERC) director Tim White was one of the lead scientists on the project, which involved an international team of researchers, including UCMP Faculty Curator Leslea Hlusko. To learn more about Ardi, Breakthrough of the Year, read this article in today's issue of Science, watch this video, also on Science's website, and read this article on BBC news. For more links and more info on the discovery of Ardi, visit the UCMP's previous blog post.

Paleo Video: A modern day dinosaur extinction

During the Cretaceous, dome-headed pachycephalosaurs roamed through what is now the Hell Creek Formation, covering parts of Montana, Wyoming, and North and South Dakota. But UCMP Curator Mark Goodwin and Museum of the Rockies Curator Jack Horner argue that there were fewer pachycephalosaur species than we thought. Mark and Jack suggest that two species, Dracorex hogwartsia and Stygimoloch spinifer, are actually juveniles and teenagers of the species Pachycephalosaurus wyomingensis. Learn about this modern day dinosaur extinction — read Mark and Jack's paper, published this week in the open access journal PLoS ONE, read the UC Berkeley News press release on the study, and watch this video!