It is an image commonly promoted by museums and dinosaur aficionados. Sue's remains, in fact, exhibit holes in her jaw that some believed were battle scars, the result of conflict with another dinosaur, possibly another T. rex.
But a new study, published today (Sept. 29, 2009) in the online journal Public Library of Science One, provides evidence that Sue, perhaps the most famous dinosaur in the world, was felled in more mundane fashion by a lowly parasite that still afflicts modern birds. The study, conducted by an international team of researchers led by Ewan D.S. Wolff of the University of Wisconsin-Madison and Steven W. Salisbury of the University of Queensland, Australia, pins the demise of Sue and other tyrannosaurs with similar scars on an avian parasitic infection called trichomonosis, caused by a single-celled parasite that causes similar pathologies on the mandibles of modern birds, raptors in particular.
It is possible the infection in her throat and mouth may have been so acute that the 42-foot-long, 7-ton dinosaur starved to death, says Wolff, a vertebrate paleontologist and a third-year student at the UW-Madison School of Veterinary Medicine. Co-authors of the study include famed paleontologist John R. Horner of the Museum of the Rockies, which funded the study, and David J. Varricchio of Montana State University.
The focus of the new study was a survey of lesions on the jaws of Sue and nine other tyrannosaur specimens. The lesions had previously been attributed to bite wounds or, possibly, a bacterial infection.
"What drew my attention to trichomonosis as a potential candidate for these mysterious lesions on the jaws of tyrannosaurs is the manifestation of the effects of the disease in [bird] raptors," explains Wolff. "When we started looking at trichomonosis in greater depth, there was a story that matched some lines of evidence for transmission of the disease in tyrannosaurs."
In birds, trichomonosis is caused by a protozoan parasite called Trichomonas gallinae. It can be transmitted from birds such as pigeons, which commonly carry the parasite but often suffer few ill effects, to raptors such as falcons and hawks, where it causes serious lesions in the mandibles. The pattern of lesions, says Wolff, closely matches the holes in the jaws of tyrannosaurs and occurs in the same anatomical location.
The scars of combat among tyrannosaurs and other dinosaurs, Wolff notes, are not uncommon, but differ notably from the lesions that are the focus of the current study. The holes caused by trichomonosis tend to be neat and have relatively smooth edges, while bite marks are often messy, and they scar and puncture bone in ways that are not readily comparable.
Tyrannosaurs, notes Wolff, are known to have been gregarious, intermingling, fighting amongst themselves, and sometimes eating one another. Transmission of the parasite may have been through salivary contact or cannibalism, he says, noting that there is no known evidence of trichomonosis in other dinosaurs.
"This leads us to suspect that tyrannosaurs might have been the source of the disease and its transmission in its environment," Wolff says.
For the disease to manifest itself in the jaws of Sue and other tyrannosaurs, it would have had to be at an advanced stage as the parasite typically sets up housekeeping as a film in the back of the throat.
"The lesions we observe on Sue suggest a very advanced stage of the disease and may even have been the cause of her demise," says Wolff. "It is a distinct possibility as it would have made feeding incredibly difficult. You have to have a viable pharynx. Without that, you won't make it for very long, no matter how powerful you are."
Ewan D. S. Wolff | EurekAlert!
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Life Sciences
19.07.2018 | Earth Sciences
19.07.2018 | Social Sciences