“If these sea turtles do, in fact, form a tightly knit group, evolutionarily speaking, the [African] specimen provides proof that members of that group survived the mass extinction at the end of the Cretaceous.” — Timothy Myers, SMU
Live Science Senior Writer Laura Geggel covered the research of paleontologist Timothy Scott Myers, a postdoctoral researcher in SMU’s Roy M. Huffington Department of Earth Sciences.
Myers analyzed an ancient sea turtle, discovered in Angola in 2012, with a triangular-shaped head that lived about 64 million years ago and that is closely related to earlier sea turtles that lived before scientists think an asteroid smashed into the earth sparking a massive mass extinction event.
The article “Tough Turtle: Dino-Killing Asteroid Spared Sea Creature,” cites new findings from Myers’ research, which studied the specimen. It was found along sea cliffs near the town of Landana, in the Angolan province of Cabinda in June 2012.
By Laura Geggel
Live Science
Shortly after an asteroid smashed into Earth about 65.5 million years ago, obliterating much of life on Earth,an ancient sea turtle with a triangular-shaped head swam along the relatively arid shores of southern Africa, a new study finds.
The creature, a newly identified species, lived about 64 million years ago during the Paleocene, an epoch within the Paleogene period, the researchers said. The animal is closely related to earlier sea turtles that lived before the asteroid struck, an event known as the Cretaceous–Paleogene (K-Pg) boundary, which marks the mass extinction that killed about 75 percent of all species on Earth, including the nonavian dinosaurs.
“If these sea turtles do, in fact, form a tightly knit group, evolutionarily speaking, then the [African] specimen provides proof that members of that group survived the mass extinction at the end of the Cretaceous,” study lead researcher Timothy Myers, a research assistant professor in the Department of Earth Sciences at Southern Methodist University in Texas, told Live Science in an email.
Paleontologists found the specimen along the sea cliffs near the town of Landana, in the Angolan province of Cabinda in June 2012. Study senior researcher Louis Jacobs, a vertebrate paleontologist at Southern Methodist University, noticed part of the bone protruding from the rock. He and his team soon realized it was a nearly complete turtle skull and most of a hyoid, a U-shaped neck bone that supports the tongue.
SMU scientists and their research have a global reach that is frequently noted, beyond peer publications and media mentions.
By Margaret Allen
SMU News & Communications
It was a good year for SMU faculty and student research efforts. Here is a small sampling of public and published acknowledgements during 2015:
Hot topic merits open access
Taylor & Francis, publisher of the online journal Environmental Education Research, lifted its subscription-only requirement to meet demand for an article on how climate change is taught to middle-schoolers in California.
Co-author of the research was Diego Román, assistant professor in the Department of Teaching and Learning, Annette Caldwell Simmons School of Education and Human Development.
Román’s research revealed that California textbooks are teaching sixth graders that climate change is a controversial debate stemming from differing opinions, rather than a scientific conclusion based on rigorous scientific evidence.
Research makes the cover of Biochemistry
Drugs important in the battle against cancer were tested in a virtual lab by SMU biology professors to see how they would behave in the human cell.
A computer-generated composite image of the simulation made the Dec. 15 cover of the journal Biochemistry.
Scientific articles about discoveries from the simulation were also published in the peer review journals Biochemistry and in Pharmacology Research & Perspectives.
The researchers tested the drugs by simulating their interaction in a computer-generated model of one of the cell’s key molecular pumps — the protein P-glycoprotein, or P-gp. Outcomes of interest were then tested in the Wise-Vogel wet lab.
The ongoing research is the work of biochemists John Wise, associate professor, and Pia Vogel, professor and director of the SMU Center for Drug Discovery, Design and Delivery in Dedman College. Assisting them were a team of SMU graduate and undergraduate students.
The researchers developed the model to overcome the problem of relying on traditional static images for the structure of P-gp. The simulation makes it possible for researchers to dock nearly any drug in the protein and see how it behaves, then test those of interest in an actual lab.
To date, the researchers have run millions of compounds through the pump and have discovered some that are promising for development into pharmaceutical drugs to battle cancer.
Strong interest in research on sexual victimization
Teen girls were less likely to report being sexually victimized after learning to assertively resist unwanted sexual overtures and after practicing resistance in a realistic virtual environment, according to three professors from the SMU Department of Psychology.
The finding was reported in Behavior Therapy. The article was one of the psychology journal’s most heavily shared and mentioned articles across social media, blogs and news outlets during 2015, the publisher announced.
The study was the work of Dedman College faculty Lorelei Simpson Rowe, associate professor and Psychology Department graduate program co-director; Ernest Jouriles, professor; and Renee McDonald, SMU associate dean for research and academic affairs.
Consumers assume bigger price equals better quality
Even when competing firms can credibly disclose the positive attributes of their products to buyers, they may not do so.
Instead, they find it more lucrative to “signal” quality through the prices they charge, typically working on the assumption that shoppers think a high price indicates high quality. The resulting high prices hurt buyers, and may create a case for mandatory disclosure of quality through public policy.
That was a finding of the research of Dedman College’s Santanu Roy, professor, Department of Economics. Roy’s article about the research was published in February in one of the blue-ribbon journals, and the oldest, in the field, The Economic Journal.
Published by the U.K.’s Royal Economic Society, The Economic Journal is one of the founding journals of modern economics. The journal issued a media briefing about the paper, “Competition, Disclosure and Signaling,” typically reserved for academic papers of broad public interest.
Chemistry research group edits special issue
Chemistry professors Dieter Cremer and Elfi Kraka, who lead SMU’s Computational and Theoretical Chemistry Group, were guest editors of a special issue of the prestigious Journal of Physical Chemistry. The issue published in March.
The Computational and Theoretical research group, called CATCO for short, is a union of computational and theoretical chemistry scientists at SMU. Their focus is research in computational chemistry, educating and training graduate and undergraduate students, disseminating and explaining results of their research to the broader public, and programming computers for the calculation of molecules and molecular aggregates.
The special issue of Physical Chemistry included 40 contributions from participants of a four-day conference in Dallas in March 2014 that was hosted by CATCO. The 25th Austin Symposium drew 108 participants from 22 different countries who, combined, presented eight plenary talks, 60 lectures and about 40 posters.
CATCO presented its research with contributions from Cremer and Kraka, as well as Marek Freindorf, research assistant professor; Wenli Zou, visiting professor; Robert Kalescky, post-doctoral fellow; and graduate students Alan Humason, Thomas Sexton, Dani Setlawan and Vytor Oliveira.
There have been more than 75 graduate students and research associates working in the CATCO group, which originally was formed at the University of Cologne, Germany, before moving to SMU in 2009.
Vertebrate paleontology recognized with proclamation
Dallas Mayor Mike Rawlings proclaimed Oct. 11-17, 2015 Vertebrate Paleontology week in Dallas on behalf of the Dallas City Council.
The proclamation honored the 75th Annual Meeting of the Society of Vertebrate Paleontology, which was jointly hosted by SMU’s Roy M. Huffington Department of Earth Sciences in Dedman College and the Perot Museum of Science and Nature. The conference drew to Dallas some 1,200 scientists from around the world.
Making research presentations or presenting research posters were: faculty members Bonnie Jacobs, Louis Jacobs, Michael Polcyn, Neil Tabor and Dale Winkler; adjunct research assistant professor Alisa Winkler; research staff member Kurt Ferguson; post-doctoral researchers T. Scott Myers and Lauren Michael; and graduate students Matthew Clemens, John Graf, Gary Johnson and Kate Andrzejewski.
The host committee co-chairs were Anthony Fiorillo, adjunct research professor; and Louis Jacobs, professor. Committee members included Polcyn; Christopher Strganac, graduate student; Diana Vineyard, research associate; and research professor Dale Winkler.
KERA radio reporter Kat Chow filed a report from the conference, explaining to listeners the science of vertebrate paleontology, which exposes the past, present and future of life on earth by studying fossils of animals that had backbones.
SMU earthquake scientists rock scientific journal
Modelled pressure changes caused by injection and production. (Nature Communications/SMU)
Findings by the SMU earthquake team reverberated across the nation with publication of their scientific article in the prestigious British interdisciplinary journal Nature, ranked as one of the world’s most cited scientific journals.
The article reported that the SMU-led seismology team found that high volumes of wastewater injection combined with saltwater extraction from natural gas wells is the most likely cause of unusually frequent earthquakes occurring in the Dallas-Fort Worth area near the small community of Azle.
The research was the work of Dedman College faculty Matthew Hornbach, associate professor of geophysics; Heather DeShon, associate professor of geophysics; Brian Stump, SMU Albritton Chair in Earth Sciences; Chris Hayward, research staff and director geophysics research program; and Beatrice Magnani, associate professor of geophysics.
The article, “Causal factors for seismicity near Azle, Texas,” published online in late April. Already the article has been downloaded nearly 6,000 times, and heavily shared on both social and conventional media. The article has achieved a ranking of 270, which puts it in the 99th percentile of 144,972 tracked articles of a similar age in all journals, and 98th percentile of 626 tracked articles of a similar age in Nature.
“It has a very high impact factor for an article of its age,” said Robert Gregory, professor and chair, SMU Earth Sciences Department.
The scientific article also was entered into the record for public hearings both at the Texas Railroad Commission and the Texas House Subcommittee on Seismic Activity.
Researchers settle long-debated heritage question of “The Ancient One”
The skull of Kennewick Man and a sculpted bust by StudioEIS based on forensic facial reconstruction by sculptor Amanda Danning. (Credit: Brittany Tatchell)
The research of Dedman College anthropologist and Henderson-Morrison Professor of Prehistory David Meltzer played a role in settling the long-debated and highly controversial heritage of “Kennewick Man.”
Also known as “The Ancient One,” the 8,400-year-old male skeleton discovered in Washington state has been the subject of debate for nearly two decades. Argument over his ancestry has gained him notoriety in high-profile newspaper and magazine articles, as well as making him the subject of intense scholarly study.
Officially the jurisdiction of the U.S. Army Corps of Engineers, Kennewick Man was discovered in 1996 and radiocarbon dated to 8500 years ago.
Because of his cranial shape and size he was declared not Native American but instead ‘Caucasoid,’ implying a very different population had once been in the Americas, one that was unrelated to contemporary Native Americans.
But Native Americans long have claimed Kennewick Man as theirs and had asked for repatriation of his remains for burial according to their customs.
Meltzer, collaborating with his geneticist colleague Eske Willerslev and his team at the Centre for GeoGenetics at the University of Copenhagen, in June reported the results of their analysis of the DNA of Kennewick in the prestigious British journal Nature in the scientific paper “The ancestry and affiliations of Kennewick Man.”
The results were announced at a news conference, settling the question based on first-ever DNA evidence: Kennewick Man is Native American.
The announcement garnered national and international media attention, and propelled a new push to return the skeleton to a coalition of Columbia Basin tribes. Sen. Patty Murray (D-WA) introduced the Bring the Ancient One Home Act of 2015 and Washington Gov. Jay Inslee has offered state assistance for returning the remains to Native Tribes.
Science named the Kennewick work one of its nine runners-up in the highly esteemed magazine’s annual “Breakthrough of the Year” competition.
The research article has been viewed more than 60,000 times. It has achieved a ranking of 665, which puts it in the 99th percentile of 169,466 tracked articles of a similar age in all journals, and in the 94th percentile of 958 tracked articles of a similar age in Nature.
In “Kennewick Man: coming to closure,” an article in the December issue of Antiquity, a journal of Cambridge University Press, Meltzer noted that the DNA merely confirmed what the tribes had known all along: “We are him, he is us,” said one tribal spokesman. Meltzer concludes: “We presented the DNA evidence. The tribal members gave it meaning.”
Prehistoric vacuum cleaner captures singular award
Paleontologists Louis L. Jacobs, SMU, and Anthony Fiorillo, Perot Museum, have identified a new species of marine mammal from bones recovered from Unalaska, an Aleutian island in the North Pacific. (Hillsman Jackson, SMU)
Science writer Laura Geggel with Live Science named a new species of extinct marine mammal identified by two SMU paleontologists among “The 10 Strangest Animal Discoveries of 2015.”
The new species, dubbed a prehistoric hoover by London’s Daily Mail online news site, was identified by SMU paleontologist Louis L. Jacobs, a professor in the Roy M. Huffington Department of Earth Sciences, Dedman College of Humanities and Sciences, and paleontologist and SMU adjunct research professor Anthony Fiorillo, vice president of research and collections and chief curator at the Perot Museum of Nature and Science.
Jacobs and Fiorillo co-authored a study about the identification of new fossils from the oddball creature Desmostylia, discovered in the same waters where the popular “Deadliest Catch” TV show is filmed. The hippo-like creature ate like a vacuum cleaner and is a new genus and species of the only order of marine mammals ever to go extinct — surviving a mere 23 million years.
Desmostylians, every single species combined, lived in an interval between 33 million and 10 million years ago. Their strange columnar teeth and odd style of eating don’t occur in any other animal, Jacobs said.
As noted by the CERN Courier — the news magazine of the CERN Laboratory in Geneva, which hosts the Large Hadron Collider, the world’s largest science experiment — more than 250 scientists from 30 countries presented more than 200 talks on a multitude of subjects relevant to experimental and theoretical research. SMU physicists presented at the conference.
The SMU organizing committee was led by Fred Olness, professor and chair of the SMU Department of Physics in Dedman College, who also gave opening and closing remarks at the conference. The committee consisted of other SMU faculty, including Jodi Cooley, associate professor; Simon Dalley, senior lecturer; Robert Kehoe, professor; Pavel Nadolsky, associate professor, who also presented progress on experiments at CERN’s Large Hadron Collider; Randy Scalise, senior lecturer; and Stephen Sekula, associate professor.
Sekula also organized a series of short talks for the public about physics and the big questions that face us as we try to understand our universe.
Every toothed pterosaur identified from North America’s Cretaceous has been discovered in North Texas. New species marks only the third.
A new species of toothy pterosaur is a native of Texas whose closest relative is from England.
The new 94-million-year-old species, named Cimoliopterus dunni, is strikingly similar to England’s Cimoliopterus cuvieri.
Identification of the new flying reptile links prehistoric Texas to England, says paleontologist Timothy S. Myers, Southern Methodist University, Dallas, who identified the fossil as a new species.
Pterosaur relatives from two continents suggests the prehistoric creatures moved between North America and England earlier in the Cretaceous — despite progressive widening of the North Atlantic Ocean during that time.
The Texas and English Cimoliopterus cousins are different species, so some evolutionary divergence occurred.
That indicates the populations were isolated from one another at 94 million years ago, Myers said.
The similarity between the two species, however, implies minimal divergence time, so gene flow between North American and European populations would have been possible at some point shortly before that date.
“The Atlantic opened the supercontinent Pangea like a zipper, separating continents and leaving animal populations isolated, so gene flow ceased and we start to see evolutionary divergence,” said Myers, a research assistant professor in the Roy M. Huffington Department of Earth Sciences at SMU. “Animals start to look different and you see different species on one continent versus another. Pterosaurs are a little trickier because unlike land animals they can fly and disperse across bodies of water. The later ones are pretty good flyers.”
Based on fossils discovered so far, it’s known that toothed pterosaurs are generally abundant during the Cretaceous in Asia, Europe and South America. But they are rare in North America.
The new Texas native, Cimoliopterus dunni, is only the third pterosaur species with teeth from the Cretaceous of North America. All three of the toothy Cretaceous-era pterosaurs discovered so far from North America are Texans. Nevertheless, Cimoliopterus dunni is most closely related to England’s Cimoliopterus cuvieri, said Myers.
The Cretaceous spanned about 80 million years from 145 million years ago to 66 million years ago.
Each of the Texas pterosaurs was discovered near Dallas.
Pterosaurs can cross marine barriers between emergent landmasses, effectively ‘island hopping’ Besides the new 94-million-year-old Cimoliopterus dunni, Myers in 2010 identified the 96-million-year-old Aetodactylus halli, a close cousin to Cimoliopterus. The third Texas pterosaur, 105-million-year-old Coloborhynchus wadleighi, was identified in 1994 by then-SMU student Yuong-Nam Lee. It too has an English connection: The first Coloborhynchus species ever described is from England.
“Given the small sample size, it’s odd that we have two that are so closely related to the English species,” Myers said. “It’s hard to draw any statistically significant conclusions from that, but it definitely indicates this is not a one-off, and that there was some relatively strong, significant connection. Two means a lot more than one in this case.”
Myers isn’t suggesting a land bridge. But scientists have suggested the sea level of the North Atlantic fluctuated over time.
“Pterosaurs don’t necessarily need land bridges to disperse because they can cross marine barriers between emergent landmasses, effectively ‘island hopping’ from one continental mass to another,” Myers said.
Nevertheless, identification of the new toothy Texas pterosaur deepens a mystery surrounding the flying reptiles: There still is no evidence of close ties between North American and South American pterosaur populations, he said.
“There are toothed pteranodontoids in South America — lots of individuals and lots of different species — but no close relatives to the toothed pteranodontoids in North America,” he said. “That might indicate there was some barrier to dispersal from the south. It’s unusual we don’t see a connection between these pterosaur populations. Maybe we will when we find more of this material.”
A long-lived group, whether toothy and small, or toothless and big
As a group, pterosaurs, which lived alongside dinosaurs, were long-lived. They survived about 162 million years, from the Late Triassic, 228 million years ago, through the Cretaceous, 66 million years ago.
Pterosaurs were among the earliest vertebrates to steadily flap their wings to power their flying.
Early forms were toothy and had wingspans similar to a flying fox, while later they were toothless and as large as fighter jets.
Pterosaurs nested on land but their bones are often recovered from shallow marine rocks. Some species have slender, pointed teeth, suitable for a diet of fish.
“This group is very abundant around the world in the middle Cretaceous — except in North America. The only evidence we have of the toothed members comes from Texas,” Myers said. “In general we see a broad trend in pterosaurs away from teeth, so at the end of the Cretaceous all known species are toothless.”
Pterosaur hunted fish offshore from North America’s Interior Seaway Cimoliopterus dunni likely hunted fish just off shore in the shallow Western Interior Seaway.
The prehistoric Seaway covered the central United States and Canada, extending from the Gulf of Mexico to the Arctic Ocean.
Myers identified the new pterosaur from a partial upper jaw — specifically the tip of the blunt snout, or rostrum. The rostrum has sockets for 13 pair of teeth. Atop the snout is a thin, prominent crest that starts near the front and extends back. The crest is fully fused to the jaw, a good indicator the pterosaur was not a juvenile, Myers said.
“The crest is really striking,” he said. “It’s almost preserved in its entirety.”
Prolific amateur collector Brent Dunn discovered the upper jaw in January 2013 while walking the spillway of Lake Lewisville north of Dallas. The fossil, coated in reddish mud, had weathered out of the ground. The marine shale layer in which it was found is part of the Eagle Ford Group, a rock unit unique to Texas.
The fossil was found alongside ammonites and crustaceans, called index fossils, because they date the shale layer. Ammonites also indicate an open marine environment, with no fresh water influence.
Although Cimoliopterus dunni would have been large, it was mid-sized as pterosaurs go, with a wingspan of about 6 feet.
“It wouldn’t have been small and cute,” Myers said. “You would have thought twice about approaching it.”
It’s fortunate to have the beautifully preserved fossil because the potential for preserving pterosaur bones is low, Myers said. Their bones were light and hollow, filled with vacuities to help them fly, so they tend to crush easily and break into pieces. “So their normal cylindrical bone is pancaked flat,” he said.
Dunn, a long-time member of the Dallas Paleontological Society, donated it to SMU’s Shuler Museum of Paleontology. He died in 2013. Myers named the fossil for Dunn. — Margaret Allen, SMU
The Guardian reporter David Hambling covered the research of SMU paleontologist Timothy S. Myers in the London newspaper’s daily Weatherwatch column.
Myers’ recent research has focused on the climate of the Jurassic, testing the notion that the era’s ancient climate was similar to modern. His most recent study found that climate was more variable than previously understood in the area now covered by the Morrison Formation, a massive and prolific fossil bearing formation that runs throughout a large portion of the western United States.
Prior to this study, a previous one set out to discover whether the modern relationship between lush environments and a proliferation of animal life held true 150 million years ago during the Late Jurassic when dinosaurs roamed the Earth.
Paleosol matrix was collected in the field by SMU paleontologist Timothy S. Myers for chemical analysis. (Myers, SMU)
Myers’ uses geochemical analysis of ancient soil, called paleosols, to unearth climate data from the Jurassic.
His findings suggest that scientists must use different approaches to quantify paleoclimate, he said.
“It’s not enough to just look at soil types and draw conclusions about the paleoclimate,” Myers said. “It’s not even enough to look at rainfall in this quantitative fashion. There are numerous factors to consider.”
Myers analyzed 22 paleosol samples from northern New Mexico, 15 from northern Wyoming and seven from southern Montana.
The samples from Montana were younger than those from New Mexico, but roughly contemporary with the samples from Wyoming.
Study found this Wyoming area surprisingly was more arid than its counterpart in New Mexico. (Credit: Myers, SMU)
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“We found that, indeed, New Mexico was relatively arid,” Myers said. “But the surprising part was that the Wyoming locality was more arid and had less rainfall than New Mexico, even though it was at a higher latitude, and above the mid-latitude arid belt. And the Montana locality, which is not far from the Wyoming locality, had the highest rainfall of all three. And there’s a very abrupt transition between the two.”
Co-authors of the study were Neil J. Tabor, SMU earth sciences professor and an expert in ancient soil, and Nicholas Rosenau, a stable isotope geochemist, Dolan Integration Group.
By David Hambling
The Guardian
We need to understand the conditions of earlier eras to make sense of climate change data. But past conditions were complex; the Jurassic world was, after all, not an unbroken vista of volcanoes and steamy jungle.
Timothy Myers, a palaeontologist at the Southern Methodist University in Dallas, collected 44 samples of ancient soils, or paleosols, from parts of the Morrison formation in the US south-west.
Researchers may assume that soil type gives a good indication of the prevailing climate. The reasoning, here, was that New Mexico, as today, would have been more arid than Wyoming and Montana further to the north.
Yet when Myers did the first detailed quantitative study, he found that mean average rainfall was 76cm (30in) for New Mexico and 114cm (45in) for north Montana, while being just 51cm (20in) in northern Wyoming.
There were big differences even between adjacent sites. “The apparently sudden shift from dry to relatively wet environments over such a short distance was perplexing,” said Myers. Normally this sort of pattern would only occur on opposite sides of a topographic feature, such as a mountain range.
Myers suggested that precipitation could have been highly seasonal at the Wyoming site, and this could have distorted the estimate for the total rainfall.
SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.
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First detailed chemical analysis of ancient soil from the Morrison Formation — a massive source of significant dinosaur discoveries for more than 100 years— reveals there was an unexpected abrupt change from arid to wet environments during the Jurassic.
The climate 150 million years ago of a large swath of the western United States was more complex than previously known, according to new research from Southern Methodist University, Dallas.
It’s been held that the climate during the Jurassic was fairly dry in New Mexico, then gradually transitioned to a wetter climate northward to Montana.
But based on new evidence, the theory of a gradual transition from a dry climate to a wetter one during the Jurassic doesn’t tell the whole story, says SMU paleontologist Timothy S. Myers, lead author on the study.
Geochemical analysis of ancient soils, called paleosols, revealed an unexpected and mysterious abrupt transition from dry to wet even though some of the samples came from two nearby locales, Myers said.
Myers discovered the abrupt transition through geochemical analysis of more than 40 ancient soil samples.
Paleosol matrix was collected in the field by SMU paleontologist Timothy S. Myers for chemical analysis of the ancient soil by grinding it to a powder, which was then fused into a glass disc for elemental analysis. (Myers, SMU)
He collected the samples from the Morrison Formation, a vast rock unit that has been a major source of significant dinosaur discoveries for more than 100 years.
The Morrison extends from New Mexico to Montana, sprawling across 13 states and Canada, formed from sediments deposited during the Jurassic.
Myers’ study is the first in the Morrison to significantly draw on quantitative data — the geochemistry of the rocks.
The abrupt transition, Myers says, isn’t readily explained.
“I don’t have a good explanation,” he said. “Normally when you see these dramatic differences in climate in areas that are close to one another it’s the result of a stark variation in topography. But in this case, there weren’t any big topographic features like a mountain range that divided these two localities in the Jurassic.”
Surprisingly, paleosols from the sample areas did not reveal marked differences until they were analyzed using geochemical weathering indices.
Paleosol samples from the Jurassic in Wyoming indicate this area of the massive Morrison Formation surprisingly was more arid than its counterpart in New Mexico. (Credit: Myers, SMU)
“It’s sobering to think that by just looking at the paleosols superficially at these localities, they don’t appear incredibly different. We see the same types of ancient soils in both places,” Myers said. “So these are some fairly major climate differences that aren’t reflected in the basic ancient soil types. Yet this is what a lot of scientists, myself included, depend on for a first pass idea of paleoclimate in an area — certain types of soils form in drier environments, others in wetter, others in cooler, that sort of thing.”
That didn’t hold true for the current study.
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With the geochemical analysis, Myers estimated the mean average precipitation during the Jurassic for northern Montana was approximately 45 inches, 20 inches for northern Wyoming and 30 inches for New Mexico.
“This changes how we view the distribution of the types of environments in the Morrison,” Myers said. “Too many times we talk about the Morrison as though it was this monolithic unit sprinkled with patchy, but similar, variations. But it’s incredibly large. It spans almost 10 degrees of latitude. So it’s going to encompass a lot of different environments. Regions with broadly similar climates can have internal differences, even over short distances. That’s the take-home.”
Co-authors of the study were Neil J. Tabor, SMU earth sciences professor and an expert in ancient soil, and Nicholas Rosenau, a stable isotope geochemist, Dolan Integration Group.
The popular artistic representations we see today of dinosaurs in a landscape setting are based on bits of evidence from plant and animal fossils found in various places, Tabor said. While that’s based on the best information to date, it’s probably inaccurate, he said. Myers’ findings provide new insights to many studies that have been done prior to his. This will drive paleontologists and geologists to seek out more quantitative data about the ancient environment.
“The geology of the Morrison has been studied exhaustively from an observational standpoint for 100 years,” Tabor said. “I have no doubt there will be many more fossil discoveries in the Morrison, even though over the past century we’ve gained a pretty clear understanding of the plants and animals at that time. But now we can ask deeper questions about the landscape and how organisms in the ancient world interacted with their environment.”
Surprising results: Northern locale more arid than southern locale
The Morrison Formation has produced some of our most familiar dinosaurs, as well as new species never seen before. Discoveries began in the late 1800s and ultimately precipitated the Bone Wars — the fossil equivalent of California’s Gold Rush.
After Myers studied dinosaur fossils from the Morrison, he became curious about the climate. Embarking on the geochemical analysis, Myers, like scientists before him, hypothesized the climate would be similar to modern zonal circulation patterns, which are driven by the distribution of the continents. Under that hypothesis, New Mexico would be relatively arid, and Wyoming and Montana both would be wetter at the time dinosaurs roamed the landscape.
Myers analyzed 22 paleosol samples from northern New Mexico, 15 from northern Wyoming and seven from southern Montana. The samples from Montana were younger than those from New Mexico, but roughly contemporary with the samples from Wyoming.
“We found that, indeed, New Mexico was relatively arid,” Myers said. “But the surprising part was that the Wyoming locality was more arid and had less rainfall than New Mexico, even though it was at a higher latitude, and above the mid-latitude arid belt. And the Montana locality, which is not far from the Wyoming locality, had the highest rainfall of all three. And there’s a very abrupt transition between the two.”
During the Jurassic, the Morrison was between 30 degrees north and 45 degrees north, which is about five degrees south of where it sits now. Its sediments were deposited from 155 to 148 million years ago. Some areas show evidence of a marine environment, but most were continental. The mean average precipitation determined for the Jurassic doesn’t match our modern distribution, Myers said.
Study underscores that understanding climate requires multiple approaches
Previously scientists speculated on the climate based on qualitative measures, such as types of soils or rocks, or types of sedimentary structures, and inferred climate from that.
“I tried to find quantitative information, but no one had done it,” Myers said. “There are entire volumes about Morrison paleoclimate, but not a single paper with quantitative estimates. Given the volume of important fossils that have come out of the Morrison, and how significant this formation is, it just struck me as important that it be done.”
Myers classified the fossil soils according to the Mack paleosol classification, and established the elemental composition of each one to determine how much weathering the paleosols had undergone.
“There are some elements, such as aluminum, that are not easily weathered out of soils,” Myers said. “There are others that are easily flushed out. We looked at the ratio of the elements, such as aluminum versus elements easily weathered. From that, we used the ratios to determine how weathered or not the soil was.”
These findings suggest that scientists must use different approaches to quantify paleoclimate, he said.
“It’s not enough to just look at soil types and draw conclusions about the paleoclimate,” Myers said. “It’s not even enough to look at rainfall in this quantitative fashion. There are numerous factors to consider.”
SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see www.smu.edu.
SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7650.
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