South Africa and the Cradle of Sauropod-Kind

Artist's reconstruction of Pulanesaura by Gina Viglietti.

Artist’s reconstruction of Pulanesaura by Gina Viglietti.

I am happy to report on a new sauropod dinosaur from the Early Jurassic of South Africa! The dinosaur, Pulanesaura, was discovered in 2004 and has been a long time coming to press. Now, she’s finally here.

When I was maybe four or five years old, I remember reading a dinosaur book with my mother. The book described for children how dinosaurs were discovered and excavated in the field, and then how the bones were reassembled back in the lab. What I don’t remember, but I have been told, was that at some point during the explanation of how dinosaurs were unearthed, I interjected, “And then they have lunch.”

I was five years old in 1978. Fast-forward to the fall of 2004, and my 31-year-old self is standing in the rain at Spion Kop farm in the Free State of South Africa marveling at the large limb bones poking out of a section of the upper Elliot Formation. I don’t recall having lunch at that moment, but I do remember being excited, and being grateful that I was part of a team, headed by Adam Yates, charged with exploring these Early Jurassic rocks. National Geographic had sponsored our grant to pursue promising bones issuing forth from these rocks, and although we did not immediately know we had a new dinosaur, there was a good possibility we did.

Matt w tibia (1)

Myself above two tibia bones (tibiae) from what would become known as Pulanesaura in 2004 … it was a less rainy day that day.

Why South Africa? As it turns out, South Africa has many exposures of Lower Jurassic rocks that record a very significant time in dinosaur evolution. The earliest true dinosaurs appeared in the Triassic period about 235 million years ago (Ma) but remained relatively small to medium-sized animals that were in competition with other vertebrate groups vying for dominance in a harsh world. During the Triassic period, all the continents were amalgamated into a single supercontinent dubbed Pangea. Although to a modern traveler the thought of Pangea sounds amazing (imagine riding a train from North America over to Europe or driving from South America into Antarctica, Africa, or Australia), ecologically this was disastrous. A huge expanse of Pangea was landlocked and nearly devoid of water, making it both hot and uninhabitable. Moreover, sea levels were also drastically lower, creating fewer areas for marine life to thrive. Thus, Pangea took a huge toll on the animals that preceded the dinosaurs. In fact, the largest mass extinction in the past 540 million years occurred just prior to the Triassic period, wiping out a majority of life on the planet.

During the Early Jurassic (starting about 200 Ma), Pangea began to unzip and break up into separate landmasses, and part of the effect of this was to bring water into regions it hadn’t been in millions of years, supporting more plants and, in turn, the animals that fed on them. It is also at this critical juncture that the sauropodomorph dinosaurs began to become larger-bodied and more diverse so that by the end of the Jurassic period (about 145 Ma), many of these herbivores were tipping the scales at 20-30 metric tons! Sauropodomorphs started out as small to medium-sized bipedal herbivores that used their long necks and grasping hands to consume foliage at different heights in their environment. Sauropods became fully quadrupedal giants with elongate necks that acted as efficient food-gathering feeding booms, sweeping across swaths of vegetation while the herbivore stayed put. And this transition from mostly bipedal herbivores eating with their hands and necks to giant quadrupeds that relied solely on long necks to feed occurred right around the Early Jurassic period about 200 Ma. So, if you want to understand the beginnings of this trend towards gigantism in the sauropodomorph dinosaurs, you need to search for fossils in Early Jurassic rocks … and that brings us back to me standing in the rain at Spion Kop on the upper Elliot Formation staring at the large bones coming out of the ground.

Those bones we were unearthing would end up being a sauropod new to science named Pulanesaura that my colleagues and I have published on this week in Nature Scientific Reports. The lead author, Blair McPhee, is a Ph.D. student at the University of Witwatersrand in South Africa who took on this dinosaur for his dissertation. Remember that we discovered Pulanesaura in 2004?  Why didn’t we publish on this animal earlier? For a number of reasons collectively called life. Between 2009 and 2011, we did publish on two other sauropodomorph dinosaurs from Spion Kop, so that took up some time. But more significantly, Adam Yates and I had major life-changing moves to new employers: Adam to the Museum of Central Australia in Alice Springs; me to Stockton University. And so poor Pulanesaura was languishing. Therefore, when Blair approached us about describing Pulanesaura for his Ph.D., we were enthusiastically supportive. I was especially pleased to see Blair at the helm of the description. I am beyond happy that a South African Ph.D. student is the lead author on the description of a native South African dinosaur. His persistence and perseverance on this project is why the world now knows about Pulanesaura.

Why Pulanesaura? Well, the name means “rain bringer” in Sesotho, which is fitting since we always seemed to get rained on during the excavation of this dinosaur. And the publication of “Rain Bringer” has finally brought home a trilogy of sauropodomorph dinosaurs and the complex story they tell of what was happening in the Early Jurassic at what is now the Spion Kop farm.

First things first – how do we know Pulanesaura is a sauropod? A number of clues point the way. For one thing, although we did not find a skull, we found teeth. The teeth of sauropods, unlike their sauropodomorph brethren, have a spoon- or spatula-like profile and have wrinkled enamel. The teeth of Pulanesaura certainly fit the bill there.

Next, being large, sauropods braced their vertebral column with extra joints in their backbones (vertebrae) – a portion of this extra joint is called the hyposphene. The body vertebrae we have of Pulanesaura only preserve their tops (the hyposphene is located on the bottom-half of the vertebra) but luckily a full tail (caudal) vertebra is preserved, and that has a hyposphene. We are also fortunate that part of the forelimb was preserved. The ulna bone in sauropods cradles the other forearm bone, the radius, by wrapping around it from behind. In sauropods, a wide, triangular depression is present on the ulna where the radius sits. Although the ulna of Pulanesaura is a bit crushed and scrappy, it was intact enough to show that, yes, indeed, such a depression for the radius was there. These features and more showed us that this dinosaur was certainly a true sauropod.

How do we know Pulanesaura is new to science? Using a method called cladistics, the suite of features for Pulanesaura was compared to other sauropodomorphs and sauropods from South Africa and around the globe. Its unique combination of features show that it is not a member of previously known sauropodomorph or sauropod dinosaurs, but falls along its own branch of the dinosaur family tree near the common ancestor of all sauropod dinosaurs. At the moment, it is very difficult to tell the difference between a true early sauropod and a sauropodomorph very close to the common ancestor of sauropods. Given the data we have for Pulanesaura, we find it most likely to be a very early sauropod. Certainly, future studies and perhaps more material of Pulanesaura will clarify this picture.

How big was Pulanesaura? We certainly don’t have a complete skeleton of this herbivore, but we have enough bones from enough areas of the body to infer that this animal stretched nearly 8 meters (about 26 feet) long and stood about 2 meters (about 6.5 feet) high at the hip. That may seem big, but it’s small for a sauropod.

Why is Pulanesaura significant? The traditional picture of sauropodomorph evolution is that when true sauropods came onto the scene, the other sauropodomorphs were pushed aside, their small body size and “inferior” anatomy undone by the larger herbivores. But Pulanesaurua turns this notion on its head because, living alongside it at Spion Kop were other sauropodomorph dinosaurs with very different anatomies. Adam, Johann, myself, and others have described two of these other sauropodomorphs, both also from Spion Kop. One, Aardonyx, was a 7 meter long sauropodomorph capable of assuming both a bipedal and quadrupedal posture; and another, Arcusaurus, was a small, juvenile sauropodomorph with a hold-over of more primitive features. And one of the things these other sauropodomorphs had going for them was that they could feed at different heights and use their forelimbs to direct foliage to the mouth. In contrast, the anatomy of Pulanesaura shows that it was an obligate quadruped (it could not stand bipedally on its hind legs), which would have restricted its vertical reach for vegetation compared with these other sauropodomorphs. However, the single neck (cervical) vertebra we have for Pulanesaura has joints that were spaced and angled (much like those of other sauropods) such that they would have allowed for a larger range of neck motion than in other contemporaneous sauropodomorphs. In other words, although Pulanesaura could not rear up and extend its neck into the trees, it could stand still and more efficiently crop foliage over a wider range. We suggest Pulanesaura shows us the incipient stages of what sauropods became very good at: they stood in one place and swept their tiny heads across a sea of vegetation. As the Jurassic period wore on, and vegetation became larger and more widespread, the advantages conferred by a body which conserved energy by standing still and sweeping a long neck across swaths of plants would ultimately select for sauropods and not their bipedal cousins.

It would have been difficult to explain to my five-year-old self that it would be many lunch breaks from the initial discoveries at Spion Kop to their final reveal to the public. But it has been worth the wait. I consider myself to be very fortunate to have the privilege of working with so many enthusiastic and talented people. Moreover, it is important to stress that cooperation with the farmers at Spion Kop was invaluable. Partnerships with farmers are a great benefit to paleontology in South Africa. Farmers know their land well, and they’re always spotting interesting things. It’s such a pleasure to work with people who value their heritage and to help them learn more about it. Because of such mutual respect and interest in South Africa’s prehistory, we now have a much richer picture and appreciation of a pivotal moment in sauropod dinosaur history that would not otherwise be possible.

And my inner five-year-old most certainly approves!

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The BFF Lab Students and Faculty in the Spotlight!

Black Beard the Bearded dragon,

Black Beard the Bearded dragon. Photo (c) Susan Allen/ The Richard Stockton College of New Jersey

I am excited to report that the Best Feet Forward (BFF) Lab has had its first local news story! Susan Allen at the Office of News & Media Relations at Stockton College has written a wonderful article that was distributed to the associated press today.  We thank Susan for this wonderful story, which we reproduce here in this post (see below).  All photos are copyright Susan Allen / The Richard Stockton College of New Jersey.

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Stockton College Researchers Analyze Locomotion of Modern Day Reptiles, Mammals to Understand How Dinosaurs Moved

By Susan Allen, Office of News & Media Relations, Richard Stockton College of New Jersey

Galloway Township, NJ- Caleb Bayewu, a junior Biochemistry major, cradled a bearded dragon in his hands as Cory Barnes, a senior Biology major, attached tiny reflective beads to the bumpy skin on the patient reptile’s forearm.

Caleb Bayewu, a junior Biochemistry major (left), cradled a bearded dragon in his hands as Cory Barnes (right), a senior Biology major, attached tiny reflective beads to the bumpy skin on the patient reptile’s forearm.

Caleb Bayewu, a junior Biochemistry major (left), cradled a bearded dragon in his hands as Cory Barnes (right), a senior Biology major, attached tiny reflective beads to the bumpy skin on the patient reptile’s forearm. Photo (c) Susan Allen / The Richard Stockton College of New Jersey

Black Beard, as the lizard is nicknamed, is one of three juvenile bearded dragons at The Richard Stockton College of New Jersey taking part in an animal locomotion research project aimed at better understanding how dinosaurs once moved across our planet.

After body measurements were recorded, Black Beard was placed on a treadmill surrounded by a system of three infrared cameras and plastic containers that serve as safety nets in case a reptile runner strays off course.

As soon as Bayewu shook a clear jar of jumping crickets, Black Beard sprang into action. Alex Lauffer, a junior Biology major, flipped the conveyor belt switch, the treadmill kicked on and the cameras began transmitting data to Dr. Matthew Bonnan, associate professor of Biology, and Dr. Jason Shulman, assistant professor of Physics.

Caleb Bayewu, a junior Biochemistry major from Maywood in Bergen County, shakes a jar of jumping crickets to motivate a beaded dragon to run on the treadmill. From the left, Alex Hilbmann, a sophomore Biology major from West Deptford in Gloucester County, Alex Hilbmann, a sophomore Biology major from West Deptford in Gloucester County, and Corey Barnes, a senior Biology major from Seaville in Cape May County, stand by.

Caleb Bayewu, a junior Biochemistry major from Maywood in Bergen County, shakes a jar of jumping crickets to motivate a beaded dragon to run on the treadmill. From the left, Alex Hilbmann, a sophomore Biology major from West Deptford in Gloucester County, Alex Hilbmann, a sophomore Biology major from West Deptford in Gloucester County, and Corey Barnes, a senior Biology major from Seaville in Cape May County, stand by.  Photo (c) Susan Allen / The Richard Stockton College of New Jersey

Sophomore Biology majors Kieran Tracey and Alex Hilbmann stood close by, making sure Black Beard stayed on the treadmill.

Kieran Tracey, a sophomore Biology major from Sea Isle City in Cape May County, guides a beaded dragon to the treadmill as Caleb Bayewu, a junior Biochemistry major from Maywood in Bergen County, holds a jar of crickets. Photo (c) Susan Allen/ The Richard Stockton College of New Jersey

Kieran Tracey, a sophomore Biology major from Sea Isle City in Cape May County, guides a beaded dragon to the treadmill as Caleb Bayewu, a junior Biochemistry major from Maywood in Bergen County, holds a jar of crickets. Photo (c) Susan Allen/ The Richard Stockton College of New Jersey

While Black Beard ran in place, the cameras captured the motion of each reflective bead sending real experimental data at the overwhelming rate of 120 frames-per-second to a computer program that can read and display the data as moving dots.

From behind their monitor, Bonnan, of Hammonton, and Shulman, of Egg Harbor Township, watched each step on their screen.

Dr. Matthew Bonnan, associate professor of Biology, and Dr. Jason Shulman, assistant professor of Physics, are working together with students to model dinosaur movement by studying modern day reptiles and mammals. “Given that the earliest mammals and dinosaurs had a forelimb posture not unlike lizards, they are acting as a model to test hypotheses about the transition from sprawling to upright forelimb postures,” said Bonnan. Shulman has been instrumental in analyzing the data, which is captured at 120 frames-per-second by a system of infrared cameras. “He is a big part of why we're able to do this. Without him, interpreting the data would be difficult at best,” said Bonnan. (c) Photo: Susan Allen/ The Richard Stockton College of New Jersey

Dr. Matthew Bonnan, associate professor of Biology, and Dr. Jason Shulman, assistant professor of Physics, are working together with students to model dinosaur movement by studying modern day reptiles and mammals. “Given that the earliest mammals and dinosaurs had a forelimb posture not unlike lizards, they are acting as a model to test hypotheses about the transition from sprawling to upright forelimb postures,” said Bonnan. Shulman has been instrumental in analyzing the data, which is captured at 120 frames-per-second by a system of infrared cameras. “He is a big part of why we’re able to do this. Without him, interpreting the data would be difficult at best,” said Bonnan. Photo (c) Susan Allen/ The Richard Stockton College of New Jersey

Stepping Back in Time

“Without a time machine, we can’t put dinosaurs on a treadmill,” said Bonnan, who has been fascinated with dinosaurs since he was 5 years old. Instead, bearded dragons, ferrets, rats and a Savannah monitor are “standing in for their ancestors” at the Best Foot Forward (BFF) Laboratory on the main Galloway, NJ campus.

Bridget Kuhlman, a senior Biology major, of Little Egg Harbor in Ocean County, left, and Kelsey Gamble, a senior Anthropology and Biology major, of Williamstown in Gloucester County, were in the Best Foot Forward Laboratory to gather data on ferret movement patterns. Kuhlman, said, “It’s a dream come true being able to work with ferrets. It’s getting me ready for vet school,” she said. She works as an EMT and personally owns five ferrets. Photo (c) Susan Allen/ The Richard Stockton College of New Jersey

Bridget Kuhlman (left), a senior Biology major, of Little Egg Harbor in Ocean County, left, and Kelsey Gamble (right), a senior Anthropology and Biology major, of Williamstown in Gloucester County, were in the Best Foot Forward Laboratory to gather data on ferret movement patterns. Kuhlman, said, “It’s a dream come true being able to work with ferrets. It’s getting me ready for vet school,” she said. She works as an EMT and personally owns five ferrets. Photo (c) Susan Allen/ The Richard Stockton College of New Jersey

“Given that the earliest mammals and dinosaurs had a forelimb posture not unlike lizards, they are acting as a model to test hypotheses about the transition from sprawling to upright forelimb postures,” said Bonnan.

The fossil record offers scientists a motionless slice of history. Bonnan and his team have turned to optical tracking technology to tell more of the story.

“Our ultimate goal is to realistically model and place constraints on how fossil vertebrates, such as dinosaurs and early mammals, moved their forelimbs,” Bonnan explained.

The team is quantitatively illustrating the motion of modern day reptiles and mammals and using bone shape as a common denominator to make comparisons between their laboratory stand-ins and dinosaurs.

Bonnan’s lifelong desire has been to “reconstruct long-dead animals and breathe life into old bones.”

Step-by-step, his vision is coming to life with the support of colleagues, student researchers and staff within the School of Natural Sciences and Mathematics.

Blending Physics and Biology

To model motion, math and physics come into play. Bonnan’s friend and colleague, Dr. Jason Shulman, joined the team lending his numerical analysis expertise. “Jason Shulman is a big part of why we’re able to do this. Without him, interpreting the data would be difficult at best,” said Bonnan.

Early in the Physics curriculum, students learn to calculate angles and speed, which means that undergraduates are prepared to take part in real research outside of textbook exercises Shulman said.

Sometimes Physics majors wonder why they need to study Biology and vice versa. The animal locomotion research is an example of how the sciences work together. “It’s important for students to understand concepts outside of their field—that’s an important lesson I hope we convey.

The interdisciplinary collaboration is perfect for Physics students,” said Shulman.

Campus-wide Support

The bearded dragons were donated to Bonnan by student Kiersten Stukowski, of Gloucester in Camden County. Scientists rarely have the opportunity to work on a long-term project with the same specimens as they mature explained Bonnan.

Justine Ciraolo, director of Academic Laboratories and Field Facilities, connected Bonnan with her sister, who is loaning her ferrets to the team.

One of our ferrets, "Mocha."

One of our ferrets, “Mocha.” Photo (c) Susan Allen/ The Richard Stockton College of New Jersey

When the reptiles and mammals aren’t in the lab, they are cared for by John Rokita, principal animal health lab technician, who has been instrumental in acquiring specimens for Bonnan.

“None of this would have been possible without the support of the School of Natural Sciences and Mathematics and Stockton’s Institutional Animal Care and Usage Committee. It is rare for undergraduates to get this experience. On every level this is teamwork and everyone has been incredibly helpful,” said Bonnan.

The Student Researchers

Alex Hilbmann, a sophomore Biology major, of West Deptford in Gloucester County, says he’s learned all about lizards while building a foundation to better understand the kinematics (or science of motion) during his independent study. “It wasn’t always easy to get them to run,” he admitted. Hilbmann plans to go on to medical school after Stockton.

Caleb Bayewu, a junior Biochemistry major who’s from Maywood in Bergen County, started out working with rats on the treadmill, but “they didn’t always want to move.” Since he joined the team, he’s witnessed the differences in movement among different species.

Corey Barnes, a senior Biology major, of Seaville in Cape May County, took Comparative Anatomy with Dr. Bonnan, which he says opened up his interest along the evolutionary tree. The research has really illustrated “how different their walking habits are.” Barnes is a veterinary technician at Beach Buddies Animal Hospital in Marmora and hopes to attend veterinary school.

Alex Lauffer, a junior Biology major, of Point Pleasant in Ocean County, has always had an interest in dinosaurs and reptiles. The research project was “right up my alley,” he said. The aspiring veterinary assistant has three snakes, one tarantula, one dog and a pond of koi fish. However, it was in the BFF Lab that he held his first bearded dragon. They are surprisingly calm, he said.

Kieran Tracey, a sophomore Biology major, of Sea Isle City in Cape May County, said, “I’m having a lot of fun working with lizards and watching them run,” and added that the experience is giving him important exposure to research in preparation for medical school. He looks forward to “analyzing how [the data] relates to dinosaurs.”

Bridget Kuhlman, a senior Biology major, of Little Egg Harbor in Ocean County, said, “It’s a dream come true being able to work with ferrets. It’s getting me ready for vet school,” she said. She works as an EMT and personally owns five ferrets.

Bridget Kuhlman (left) and Kelsey Gamble (right) attach tracking beads to the ferret nick-named, "Mocha" as Drs. Bonnan and Shulman look on.

Bridget Kuhlman (left) and Kelsey Gamble (right) attach tracking beads to the ferret nick-named, “Mocha” as Drs. Bonnan and Shulman look on. Photo (c) Susan Allen/ The Richard Stockton College of New Jersey

Kelsey Gamble, a senior Anthropology and Biology major, of Williamstown in Gloucester County, said, “Working with live animals is an interesting experience. It’s a lot different than my anthropology work,” she said. “We are looking at the forelimbs and how they move.” The search for patterns and constructing relationships between form and function blend her Biology and Anthropology interests.

Kelsey Gamble, a senior Anthropology and Biology major, of Williamstown in Gloucester County, said, “Working with live animals is an interesting experience. It’s a lot different than my anthropology work,” she said. “We are looking at the forelimbs and how they move.” The search for patterns and constructing relationships between form and function blend her Biology and Anthropology interests. Pictured, she holds a ferret that is taking part in the animal locomotion research project at Stockton College. Photo (c)

Kelsey Gamble, a senior Anthropology and Biology major, of Williamstown in Gloucester County, said, “Working with live animals is an interesting experience. It’s a lot different than my anthropology work,” she said. “We are looking at the forelimbs and how they move.” The search for patterns and constructing relationships between form and function blend her Biology and Anthropology interests. Pictured, she holds a ferret that is taking part in the animal locomotion research project at Stockton College. Photo (c) Susan Allen/ The Richard Stockton College of New Jersey

Contact:         Susan Allen
                        Office of News & Media Relations
                        Galloway Township, NJ 08205
                        Susan.Allen@stockton.edu
                        (609) 652-4790

The NAMS Research Symposium Winners

Just a short post to make you aware that the winners of the 2014 NAMS Research Symposium are now posted on-line.

A big series of “thank you”s is necessary.  On behalf of Tara Luke and myself, we thank each and every one of our faculty and students for such an amazing turn-out at the NAMS Research Symposium this spring!  Thanks go out to all of the NAMS staff for their help with our student research. I also want to thank the judges for their time and input:  Adam Aguiar, David Burleigh, Justine Ciraolo, Nate Hartman, Marie Jelinski, and Chrissy Schairer.  We also want to again extend our thanks to David Dimmerman and his staff for coordinating the poster printing.  Finally, we thank Dean Weiss, Provost Kesselman, and President Saatkamp for their continuing support of our student research.

The Richard Stockton College of New Jersey NAMS Research Symposium Abstracts Now On-line

The 2013 NAMS Research Symposium was very well attended, with over 40 posters and many more students and faculty.

The 2013 NAMS Research Symposium was very well attended, with over 40 posters and many more students and faculty.

This is a short post to announce that the NAMS Research Symposium abstracts are now on-line in HTML format as well as available in PDF format: NAMS Symposium 2014 -Abstract Book-.  We have 55 posters this year!

Find out more by going to the NAMS Symposium Research page.  We hope you can join us this Friday, April 25.

Combining physics and vertebrate paleontology

Often, students in biology and paleontology wonder why it is that we “force” them to take physics.  I ought to know — I was one of those students!  It wasn’t until later in graduate school that I began to appreciate the application of physics to matters of dinosaur movement.  I believe part of this reticence among many future biologists and paleontologists to embrace and understand physics is that they feel (as I once did) that it was mostly the arena of engineers and cosmologists.

Yet, the questions we are often so interested in about living organisms and those in the fossil record relate to physics.  How did they move?  Were they moving in water?  How could their heart pump blood to their head?  How did a giant sauropod move, let alone stand, without breaking its bones?  So, if you are interested in dinosaurs and other magnificent animals of the past in the context of how they went about their daily lives, then you are interested in physics.

When I first began teaching vertebrate paleontology back in 2003, my goal then as now was to communicate to biology and paleontology students how modern vertebrate skeletons and body form are related to their function.  Too often, in my opinion, we tend to emphasize taxonomy and relationships over how, as scientists, we reconstruct paleobiology.  To be clear, taxonomy and the study of evolutionary relationships (systematics) are hugely important — they provide the context in which we test evolutionary hypotheses.  However, I wanted to strike a balance in my courses of teaching how the vertebrates were related in combination with how they lived their lives and responded to the physical world.

Today in my vertebrate paleontology course at Richard Stockton College, I hope a new group of students has begun to appreciate this intersection among biology, paleontology, and physics.  In the lab, students used a small wind tunnel and “smoke” from a fog machine to test how three different fossil fishes may have moved through the water.  I have found it is one thing to talk about Bernoulli’s Principle or discuss friction and pressure drag.  It is a whole other kettle of fish (pun intended) to see for one’s self how body shape actually changes the fluid around it.

Each group of students was assigned a fossil fish to research and model out of clay in lab.  Then, after hypothesizing how they thought their particular fish would behave relative to the water current (or in this case, the air current with “smoke”), they put their models in the wind tunnel, turned on the smoke, and put their hypotheses to the test.  They will later present their findings to the class.  My hope in all of this is that these students appreciate that our hypotheses about past life rely heavily on our models of the present flesh, bone, and physical laws.

Student group modeling and studying the effect of body shape on fluid movement in the early chondrichthyan, _Cladoselache_.

Student group modeling and studying the effect of body shape on fluid movement in the early chondrichthyan, _Cladoselache_.  Our wind tunnel can be seen in the background, upper left.

The _Cladoselache_ model sculpted by students based on data from fossils.

The _Cladoselache_ model sculpted by students based on data from fossils.

The student group studying the heterostracan (jawless fish) _Drepanaspis_.

The student group studying the heterostracan (jawless fish) _Drepanaspis_.

_Drepanaspis_ model.

_Drepanaspis_ model.

The student group studying the osteostracan (jawless fish), _Hemicyclaspis_.

The student group studying the osteostracan (jawless fish), _Hemicyclaspis_.

The _Hemicyclaspis_ model.

The _Hemicyclaspis_ model.

The _Hemicyclaspis_ model in our wind tunnel, sitting on a box of clay to prop it into the (faintly visible) stream of "smoke."

The _Hemicyclaspis_ model in our wind tunnel, sitting on a box of clay to prop it into the (faintly visible) stream of “smoke.”

I want to dedicate this short post to the following people at Richard Stockton College.  First, having a wind tunnel and smoke machine would not have happened at all were it not for the help of our shop staff in the Natural Sciences — Bill Harron, Mike Farrell, and Mike Santoro.  They worked on this small scale wind tunnel with my input, and helped give our students a wonderful lab experience.

Second, Christine Shairer was invaluable for her help with getting me the materials my students and I needed to do this small-scale experiment.

Finally, third, Dr. Jason Shulman in physics who is a colleague, research collaborator, and one of the few physicists willing to put up with a paleontologist who is constantly asking what I can only assume are ignorant and humorously simple questions.  If only I had had such an enthusiastic professor when I was questioning why I had to learn physics all those years ago!

Dinosaur hand and forelimb posture might have been more diverse than previously hypothesized

Turn a doorknob and you are taking advantage of what anatomists call pronation and supination: the ability to rotate your hand palm-side down (pronation) or palm-side up (supination).  This ability stems from your bone geometry: the radius bone in your forearm is curved can pivot around your ulna, rotating your hand in the process.  Drop to the floor and crawl, and your hand is pronated by crossing the radius over the ulna just as it is for mammals which walk on all-fours like elephants, dogs, and cats.

Pronation and supination of the hand by rotating the radius bone over the ulna in humans. (c) 2013 M.F. Bonnan.

Pronation and supination of the hand by rotating the radius bone over the ulna in humans. (c) 2013 M.F. Bonnan.

In our paper published this week in PLOS ONE, my former student, Collin VanBuren (now a Ph.D. fellow at the University of Cambridge, UK) and myself suggest that most dinosaurs could not actively pronate their hands (that is, turn doorknobs) because their radius could not cross their ulna. Our conclusions were reached after analyzing the bones of nearly 300 specimens representing living birds, reptiles, mammals, and dinosaurs like Tyrannosaurus, Apatosaurus, and Triceratops.

Difference in radius bone geometry are correlated to some degree with forelimb posture.

Difference in radius bone geometry are correlated to some degree with forelimb posture.

Statistical analysis of radius geometry shows that dinosaurs most often have a straight radius bone with a non-circular head (the part that allows movement at the elbow), a shape similar to those of lizards, crocodiles, and birds.  These animals cannot actively pronate their hands, and in lizards and crocodiles this radius geometry is correlated with a non-erect forelimb posture.  In contrast, most land mammals show a curved radius geometry that enables the forelimb to be held erect and the hand to be pronated.  Mammals like ourselves have a well-rounded radial head that allows the radius to actively swivel around the ulna.  Tellingly, the only mammals in our sample that resembled reptiles, birds, and dinosaurs were the primitive, sprawling egg-laying duck-billed platypus and spiny echidna.

Our findings are significant in that they show dinosaur forelimb posture was not mammal-like and, possibly most importantly, more diverse than previously appreciated.  For example, radius shape suggests the forelimb posture and range of pronation in horned dinosaurs like Triceratops was more like those of a crocodile than a rhino.  In another example, the radius geometry of the giant, long-necked sauropods such as Apatosaurus don’t comfortably group with living reptiles, birds, or mammals, suggesting that their forelimb postures were achieved in anatomically novel ways.  Ultimately, our data strongly suggest that we must re-evaluate our conceptions of how dinosaurs could and could not use their forelimbs.

We can also breathe a sigh of relief: most predatory dinosaurs could not open our doors.

I  must give a big shout out and expression of gratitude to Collin — his dedication to this project, through several starts and stops, is what finally saw it through.  That we landed this research in a venue like PLOS ONE is that much more of a testament to his perseverance to get this science out there.  It means a lot to me that we got this out and into open-access: this represents the accumulation of some of my inferences and hypotheses on dinosaur forelimb posture since my graduate school days.  I also want to acknowledge the influence and inspiration of some fellow dinosaur forelimb fanatics, namely Ray Wilhite, Phil Senter and Heinrich Mallison.  All are colleagues and friends, and all have also in their own unique ways put dinosaur forepaws front and center — I encourage you to check out their research!

Read our paper, which is open access: http://dx.plos.org/10.1371/journal.pone.0074842

The Visit to Brown University

Radha Varadharajan at Brown with Beth Brainerd.

Radha Varadharajan at Brown with Beth Brainerd.

After spending five valuable days at Brown University, Dr. Matthew Bonnan and I learned a great deal about C-arm fluoroscopes and with XROMM technology. The early stages involved getting accustomed to the protocols of working with the fluoroscopes. This step was pivotal for the machines emit an innocuous but not neglible amount of radiation to capture the motions of our rats: Pink, Floyd, Evan, Rudy, Harry, and Taylor.  Personally, the pinnacle of the visit to Brown can be identified as the days the rats walked across the beam. With much guidance from both me and Dr. Bonnan, our furry test subjects were cajoled across the plank or dowel. Although Dr. Bonnan was the primary coaxer of our scampering participants, I was also able to give a hand in guiding them.

Within a few days into the visit, I was amazed with the advanced technologies at Brown. Comprehending the process of how the fluoroscopes operated was especially intriguing. Because I was able to accompany Dr. Bonnan on this trip to Brown University, not only did I understand the innovational technology that is XROMM, but I was also able to contribute in the smallest way possible in understanding the evolution of forelimb posture.

Here is Radha coaxing Pink the Rat through the X-ray beams.

Here is Radha coaxing Pink the Rat through the X-ray beams.

I would like to conclude this post by expressing my utmost gratitude to numerous individuals that allowed for my collaboration. My involvement in this educational visit would not have been feasible without the generous contribution of Dr. Robert Fine; Dr. Fine’s munificent gesture solely funded my trip. I would also like to thank Dr. Elizabeth Brainerd and Dr. Angela Horner for their guidance. Finally, I would like acknowledge Dr. Bonnan for his unceasing support.  Without his patience, I would not have been able to discover the numerous benefits of researching in such a compelling field.