DALLAS (SMU) – Leaf fossils from Ethiopia’s Mush Valley that date back nearly 22 million years have been found by SMU’s Earth Science professors Bonnie Jacobs and Neil J. Tabor and a dozen other international scientists.
The Mush Valley is the first site in Africa to produce an assemblage of some 2,400 leaves from that time interval, and the first to be studied using multiple lines of evidence, including associated microscopic fossils and chemical constituents, that tell us details about the ancient ecosystem.
Paleobotanical remains that an international team found in Ethiopia’s Mush Valley.
Scientists can use data from the study to answer fundamental questions, like what climate change may look like in the future. Specifically, climate scientists can take information from the study, along with other data, to test models used to estimate future global climate change.
“The past helps us to understand how ecological processes operate under conditions so different from now. It is like the Earth has done experiments for us,” said Jacobs, a world-renowned paleobotanist at SMU (Southern Methodist University).
In addition, using fossils to learn more about what Africa’s prehistoric ecosystems were like can provide context for events in the past, such as when a land bridge developed between Africa and Eurasia 24 million years ago or the environment for primate precursors to the human family.
The fossils found in this study span an interval of 60,000 years during the early Miocene Epoch, which began 23 million years ago. Ellen D. Currano, a paleoecologist at the University of Wyoming, was the lead author of the study. It was published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.
You can read more about the work that Jacobs, Currano and the international colleagues have been doing in the Mush Valley here.
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UT Southwestern Medical Center and SMU found migratory birds maximize how much light they get from their environment, so they can migrate even at night
DALLAS (SMU) – It was a puzzle about birds.
Migratory birds are known to rely on Earth’s magnetic field to help them navigate the globe. And it was suspected that a protein called cryptochrome, which is sensitive to blue light, was making it possible for birds to do this.
Yet many of these animals are also known to migrate at night when there isn’t much light available. So it wasn’t clear how cryptochrome would function under these conditions in birds.
A new study led by UT Southwestern Medical Center in collaboration with SMU (Southern Methodist University), though, may have figured out the answer to that puzzle.
Researchers found that cryptochromes from migratory birds have evolved a mechanism that enhances their ability to respond to light, which can enable them to sense and respond to magnetic fields.
“We were able to show that the protein cryptochrome is extremely efficient at collecting and responding to low levels of light,” said SMU chemist Brian D. Zoltowski, who was one of the lead authors of a new study on the findings. “The result of this research is that we now understand how vertebrate cryptochromes can respond to very low light intensities and function under night time conditions.”
The study was published in the journal PNAS in September.
(From left) UT Southwestern Medical Center research specialist Yogarany Chelliah, Dr. Joseph Takahashi, and SMU’s Dr. Brian Zoltowski. Photo courtesy of Southern Methodist University, Kim Leeson.
Cryptochromes are found in both plants and animals and are responsible for circadian rhythms in various species. In birds, scientists were specifically focused on learning more about an unusual eye protein called CRY4, which is part of a class of cryptochromes.
The lab of Joseph Takahashi, a circadian rhythms expert at UT Southwestern Medical Center, worked with other UT Southwestern scientists to purify and solve the crystal structure of the protein – the first atomic structure of a photoactive cryptochrome molecule from a vertebrate. The lab of Brian Zoltowski, an expert in blue-light photoreceptors, studied the efficiency of the light-driven reactions – identifying a pathway unique to CRY4 proteins that facilitates function under low light conditions.
“Although in plants and insects, cryptochromes are known to be photoactive, which means they react to sunlight. Among vertebrates much less is known, and the majority of vertebrate cryptochromes do not appear to be photoactive,” said Takahashi, chairman of neuroscience at UT Southwestern and an investigator with Howard Hughes Medical Institute. “This photosensitivity and the possibility that CRY4 is affected by the magnetic field make this specific cryptochrome a very interesting molecule.”
Researchers took a sample of the CRY4 from a pigeon and grew crystals of the protein. They then exposed the crystals to x-rays, making it possible for them to map out the location of all the atoms in the protein.
And while pigeons are not night-migratory songbirds, the sequences of their CRY4 proteins are very similar, the study noted.
“These structures allow us to visualize at the atomic scale how these proteins function and understand how they may use blue-light to sense magnetic fields,” said Zoltowski, associate professor of chemistry at SMU’s Dedman College of Humanities & Sciences. “The new structures also provide the first atomic level detail of how these proteins work, opening the door for more detailed studies on cryptochromes in migratory organisms.”
In the study, researchers discovered unusual changes to key regions of the protein structure that can enhance their ability to collect light from their environment.
“Cryptochromes work by absorbing a photon of light, which causes an electron to move through a sequence of amino acids. These amino acids typically consist of a chain of 3 or 4 sites that act as a wire that electrons can flow through,” explained Zoltowski. “But in pigeons, it was identified that this chain may be extended to contain 5 sites.”
This mutation of the electron chain in pigeons makes cryptochrome less dependent on a bird’s environment having a lot of light for the protein to be activated.
“Birds have evolved a mechanism to enhance the efficiency. So even when there is very little light around, they have enough signal generated to migrate,” Zoltowski said.
Other co-authors of the study include UT Southwestern’s Yogarany Chelliah, Anushka Wickramaratne, Wei Xu, Ryan E. Hibbs and Carla B. Green; SMU’s Nischal Karki; Henrik Mouritsen from the University of Oldenburg; and Peter J. Hore and Lauren Jarocha from the University of Oxford.
About SMU
SMU is the nationally ranked global research university in the dynamic city of Dallas. SMU’s alumni, faculty and nearly 12,000 students in seven degree-granting schools demonstrate an entrepreneurial spirit as they lead change in their professions, communities and the world.
Study sheds light on how the way our ancestors fed themselves changed our ecosystem
DALLAS (SMU) – Humans started making an impact on the global ecosystem through intensive farming much earlier than previously estimated, according to a new study published in the journal Science.
Evidence of the earliest domesticated plants and animals dates back to around 10,000 years ago. But findings from a team of more than 250 scientists, including two from SMU (Southern Methodist University), show that by 3,000 years ago our ancestors had dramatically changed the world to grow food.
“Our study shows in detail the progression from the origins of agriculture to its spread around the world,” said SMU anthropologist Mark D. McCoy. “It turns out that earth science models are probably too conservative, and intensive reshaping of the environment for food production was common by thousands of years before the onset of the kind of industrial scale farming we see today.
“That is important because over the time periods discussed, humans became the major force shaping ecosystems around the world,” McCoy said.
The new global assessment by the ArchaeoGLOBE Project also shows that scientists have previously underestimated the impact of early human land use.
Crowdsourcing the Map
Led by archeologist Lucas Stephens, a researcher affiliated with the Max Planck Institute for the Science of Human History, ArchaeoGLOBE used a crowdsourcing approach, inviting experts in ancient land use to contribute to a questionnaire on 146 regions (covering all continents except Antarctica) at ten historical time intervals to assess and integrate archaeological knowledge at a global scale. The result was a complete, though uneven, meta-analysis of global land use over time.
Significantly, the study also reveals that hunting and gathering was more varied and complex than originally thought, helping archeologists to recognize that foragers “may have initiated dramatic and sometimes irreversible environmental change.” Intensive forms of agriculture reported around the world included activities like clearing land, creating fields that were fixed on the landscape, raising large herds of animals, and putting increasing amounts of effort into growing food.
SMU anthropologist and ArchaeoGLOBE team member K. Ann Horsburgh notes the rise in agriculture and livestock is primarily due to growing populations needing to be fed.
“Food production such as agriculture and pastoralism, when compared with foraging in the same environment, is linked to a faster population growth and can sustain higher population densities,” said Horsburgh.
Horsburgh, Assistant Professor of Anthropology, and McCoy, Associate Professor of Anthropology, provided information on land use in Africa and the remote islands of the Pacific, respectively. McCoy also brought his expertise in geospatial technology to study how people in the past inhabited and shaped the world around them, while Horsburgh brought her knowledge of ancient DNA to retrace the spread of domesticated animals.
Mapping Ancient Migrations
The map could provide new light on how the spread of farming and herding were linked to major migrations in human prehistory.
“This is first time that regional expertise on ancient land use has been synthesized on this scale,” Horsburgh said. “That matters because we know that although the shift from foraging to farming tends to be a ‘one-way’ transition, it did not progress the same way around the world. The details of how it did progress has shaped everything from our diets to the languages we speak today.”
Horsburgh went on to say, “What remains the topic of intense study is how much of the transition is food producers spreading and displacing foragers, and how much is it foragers adopting or marrying into food producing groups, or some other scenario. Most of this was done in the absence of written records, so it is up to anthropology to sort things out.”
“The natural next step for this revised model of the spread of different types, and intensities, of land use is to compare them with human genetics and linguistics and integrate these findings into the big story of humanity,” said Horsburgh.
SMU is the nationally ranked global research university in the dynamic city of Dallas. SMU’s alumni, faculty and nearly 12,000 students in seven degree-granting schools demonstrate an entrepreneurial spirit as they lead change in their professions, communities and the world.
DALLAS (SMU) – There’s a new Texas dinosaur on the books.
SMU postdoctoral fellow Kate Andrzejewski, with University paleontologists Dale Winkler and Louis Jacobs, have identified Convolosaurus marri from fossils collected at Proctor Lake, southwest of Fort Worth.
Remnants of several dinosaurs were first found at the Comanche County lake site in 1985, and most of the fossils had been stored for years in the Shuler Museum of Paleontology at SMU. But it wasn’t until Andrzejewski, Winkler and Jacobs examined the fossils more recently that the new dinosaur was identified.
“Convolosaurus is an amazing discovery,” said Andrzejewski, whose findings were published in March in the journal PLOS ONE. “Not only because it represents a new dinosaur, but its discovery also provides unique insight into dinosaur behavior during the early Cretaceous.”
Convolosaurus marri is on view at the Perot Museum of Nature and Science in the T. Boone Pickens Life Then and Now Hall as “Proctor Lake Ornithopod.” The newly identified dinosaur was named in honor of Ray H. Marr, an SMU alumnus who is president of Marr Oil & Gas LTD and a strong supporter of SMU students.
C. marri belongs to a family of herbivorous dinosaurs called ornithopods, which are known for their bird-like stance on two legs. C. marri is believed to have been an agile and fairly small creature.
“Later members of that group became much larger and would graze on all four legs earning them the nickname ‘the cows of the Cretaceous,’” Andrzejewski said.
Andrzejewski and Dale A. Winkler, senior research fellow for ISEM at SMU, and Louis L. Jacobs, professor emeritus of Earth Sciences at SMU, were able to look at fossils from 29 different individuals that were ultimately identified as C. marri. Because of the size distribution of the fossils, it is likely the dinosaurs were a mix of recently-hatched dinosaurs and older juveniles.
“This indicates individuals grouped together after hatching and may have flocked together for protection from predators, which is where this dinosaur got its name,” Andrezejewski said. “Convolosaurus means ‘flocking lizard.’”
The collection of C. marri fossils discovered together also indicate that these dinosaurs kept occupying the same spot over time.
“However, almost all of the fossils found at this site represent Convolosaurus, with only one tooth belonging to a small carnivorous dinosaur and one skeleton of a small reptile, which is part of the same family as a crocodile.”
Furthermore, none of the bones from Convolosaurus contain any indications that they were eaten or even scavenged upon,” Andrzejewski noted. “This suggests that this dinosaur found a safe haven and perhaps used it to raise their young and thrive in a world filled with challenges – from droughts to terrifying carnivorous dinosaurs.”
It has long been suspected that there was a “nesting site” at the place where the remnants of C. marri were found, although no eggshells have yet been found.
“The discovery of Convolosaurus certainly tells an interesting and incredible story of life during the early Cretaceous of Texas,” said Andrzejewski.
A fossil mosasaur skull and partial skeleton excavated from Angola’s costal cliffs for display in “Sea Monsters Unearthed.”
When the South Atlantic ocean basin was still young, a new deep-water connection between the Southern and Northern Hemispheres allowed giant marine reptiles to move into Angola's coastal waters. Mosasaurs and sea turtles, drawn by the region's plentiful food, were among the first reptiles to prowl these waters.
“Fossils tell us about the life that once lived on Earth, and how the environments that came before us evolve over time,” said Louis Jacobs, professor emeritus of paleontology at SMU and collaborating curator for the exhibition. “Our planet has been running natural experiments on what shapes environments, and thereby life, for millions of years. If it weren’t for the fossil record, we wouldn’t understand what drives the story of life on our planet.” (Credit: Hillsman S. Jackson, Southern Methodist University)
Sea Monsters Unearthed: Life in Angola’s Ancient Seas opens Nov. 9 at National Museum of Natural History
DALLAS (SMU October 15, 2018) – Once the exhibit opens, “Sea Monsters Unearthed: Life in Angola’s Ancient Seas” will allow visitors to visually dive into the cool waters off the coast of West Africa as they existed millions of years ago when the continents of Africa and South America were drifting apart. It’s a unique opportunity to examine fossils of ancient marine reptiles and learn about the forces that continue to mold life both in out of the ocean.
But the back story is just as fascinating: SMU Emeritus Professor of Paleontology Louis Jacobs and his SMU colleague Michael Polcyn forged a partnership with collaborators in Angola, Portugal and the Netherlands to explore and excavate Angola’s rich fossil history, while laying the groundwork for returning the fossils to the West African nation. Back in Dallas Jacobs and Polcyn, director of the University’s Digital Earth Sciences Lab, and research associate Diana Vineyard went to work over a period of 13 years with a small army of SMU students to prepare the fossils excavated by Projecto PaleoAngola.
The result is a dynamic exhibit opening Nov. 9 in the Smithsonian’s National Museum of Natural History featuring large vertebrate marine reptiles from the Cretaceous Period — mosasaurs, marine turtles and plesiosaurs. This exhibit will mark the first time Angolan fossils of colossal Cretaceous marine reptiles will be on public display.
“It turns out that Angola is the best place on the surface of the earth to see the rocks that reflect and show the opening of the South Atlantic and the split between South America and Africa,” Jacobs said. But the war of independence in Angola that began in 1961 and ended (after civil war) in 2002 effectively prevented scientists from working this rich fossil zone for nearly 40 years after continental drift and plate tectonics became accepted scientific theory.
When Jacobs and the team arrived to begin digging on the coast of Angola in 2005, they were first on the scene to record this fascinating record of sea life that existed as the South Atlantic Ocean grew between two drifting continents.
SMU students did the important, time-consuming lab work
Over the past 13 years, the fossils were shipped back to Dallas, where over 100 undergraduate students have worked in basement laboratories to painstakingly clean and preserve the fossils. Some were paleontology students, most were not – but they seem to share an appreciation for their unique role in sharing new knowledge.
“Getting fossils out of rocks is a time consuming, labor-intensive operation,” Jacobs said. “But every time a student removes a grain of sand off a fossil, they have the excitement of seeing ancient life that no one else in the world has ever seen. On top of that, these fossils are going on exhibit at the Smithsonian and then back to their own homeland. That gives our students an opportunity that they simply could not get anywhere else. And what’s not to like about that?”
The Smithsonian exhibit, made possible by the Sant Ocean Hall Endowment fund, will immerse visitors in a marine environment from the Cretaceous Period, which began about 145 million years ago and ended about 66 million years ago. It features lively animations and vivid paleoart murals of life beneath the waves courtesy of natural history artist (and longtime Jacobs collaborator) Karen Carr. The exhibit brings to life 11 authentic fossils from Angola’s ancient seas, full-size fossil reconstructions of a mosasaur and a marine turtle, as well as 3-D scanned replicas of mosasaur skulls. Photomurals and video vignettes will take visitors to field sites along Angola’s modern rugged coast, where Projecto PaleoAngola scientists unearthed the fossil remains from this lost world.
“Because of our planet’s ever-shifting geology, Angola’s coastal cliffs contain the fossil remains of marine creatures from the prehistoric South Atlantic,” said Kirk Johnson, the Sant Director of the National Museum of Natural History. “We are honored by the generosity of the Angolan people for sharing a window into this part of the Earth’s unfolding story with our visitors.”
About SMU
SMU is the nationally ranked global research university in the dynamic city of Dallas. SMU’s alumni, faculty and nearly 12,000 students in seven degree-granting schools demonstrate an entrepreneurial spirit as they lead change in their professions, communities and the world. For more information, visit SMU on its website and on Facebook and Twitter.
About the National Museum of Natural History
The National Museum of Natural History is connecting people everywhere with Earth’s unfolding story. The museum is one of the most visited natural history museums in the world with approximately 7 million annual visitors from the U.S. and around the world. Opened in 1910, the museum is dedicated to maintaining and preserving the world’s most extensive collection of natural history specimens and human artifacts. It is open daily from 10 a.m. to 5:30 p.m. (closed Dec. 25). Admission is free. For more information, visit the museum on its website and on Facebook and Twitter.
In the words of smu students and graduates who sorted, cleaned and preserved fossils for Projecto Paleoangola
Pictured (L to R): Yasmin Jackson, Tania Doblado Speck, Harrison Schumann and Evan Snyder
Evan Snyder (SMU 2019)
“This experience allowed me to work on a project far bigger than myself. Exhibits just like this one excited me as a young child and led to my study of science. I’d love to think that my work will have the same impact on kids today. Working on this project also taught me how to work on challenging and stressful tasks with the right balance of confidence and care to meet deadlines with quality work.”
Yasmin Jackson (SMU 2019)
“I was able to go to the Smithsonian for the first time through this project. I really liked being able to see all of the different exhibits that are currently in the museum and imagine what our exhibit will be like in the midst of all of it.”
Harrison Schuman (SMU 2019)
“Dr. Jacobs is an inspiring individual to be around. Despite being a world-class expert in paleontology, he made himself very approachable and was always personally invested in all of the students working on the project. This kind of attitude encourages students like me to pursue careers in science.”
Alexandra Lippas (SMU 2011)
“It is because of Dr. Jacobs that I was able to be a part of this project. He encouraged students from other branches of science to work on this study. I think it demonstrates that different perspectives can lead to great discovery.”
Connor Flynn (SMU 2014)
“My time in the lab will be a source of stories for years to come and a point of pride for a lifetime. Its lessons in patience, care and passion for the labor will never be forgotten. Dr. Jacobs’ words ‘There’s nothing so broken you can’t fix it,’ carried me through more lab accidents than i care to admit — both at SMU and beyond.”
Jennifer Welch (SMU 2019)
“Dr. Jacobs is so incredibly smart, I could point out any part of the vertebrae and he would tell me what it’s for, why it was there, how that impacted the life of the animal and the stories that told about the land where the animal lived.”
Stephen Tyler Armstrong (SMU 2012)
“As an engineering major, this project exposed me to areas of research and career paths I would otherwise not encountered. It was really interesting to work so closely with those conducting the research to learn about a subject outside of my realm.”
