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Alberta is a great place for a dinosaur palaeontologist, with plenty of preserved skeletons and some of the best evidence for dinosaurs in the world.

However, in the Willow Creek Formation of southwestern Alberta, which records the last few million years before the extinction of dinosaurs, only three kinds of dinosaur skeletons have been found: Tyrannosaurus rex, an undetermined hadrosaur (duck-billed dinosaur), and an undetermined leptoceratopsid (small horned dinosaur). Were those the only dinosaurs living here during that time? Unlikely, but how do we know what dinosaurs were present if their skeletons weren’t preserved?

Unlike many geological formations in Alberta, dinosaur eggshells are quite common in the Willow Creek Formation. The ancient soils (a.k.a. paleosols) present in the formation suggest that conditions were arid to semi-arid at the time, which led to excellent preservation of dinosaur eggshell. Like skeletons, eggshells tend to be distinctive between the various kinds of dinosaurs and can be used to identify what dinosaurs were present.

A new scientific article by our Curator of Dinosaur Palaeoecology, François Therrien, in collaboration with Darla K. Zelenitsky, Kohei Tanaka, Philip J. Currie, and Christopher L. DeBuhr, presents an analysis of eggshells discovered in the Willow Creek Formation. The team inspected hundreds of dinosaur eggshells recovered from several sites in southwestern Alberta. They were able to determine that the eggshell fragments were produced by at least seven different types of dinosaurs: two ornithopods (a group of bipedal, herbivorous dinosaurs, including hadrosaurs) and five small theropods, including oviraptorosaurs, troodontids, and dromaeosaurs (colloquially, raptors). Because researchers frequently cannot correlate an eggshell with a specific species unless it is associated with a parent or a baby inside the egg, eggshells are given their own species names, in parallel to the way skeletons are named. These are called ootaxa.

Montanoolithus_04_201409181406_1800

Montanoolithus eggshell, belonging to a small theropod, was discovered in southwestern Alberta. Art by Julius T. Csotonyi.

This research triples the known dinosaur diversity of the Willow Creek Formation, from three species based on skeletons only, to at least nine known from skeletons and eggshells. In addition, it extends the known temporal range of some of the ootaxa to 10 million years and gives a better sense of the ancient ecosystem in southwestern Alberta at the end of the Age of the Dinosaurs.

The article, titled “Latest Cretaceous eggshell assemblage from the Willow Creek Formation (upper Maastrichtian – lower Paleocene) of Alberta, Canada, reveals higher dinosaur diversity than represented by skeletal remains,” was published in the January 2017 issue of the Canadian Journal of Earth Science.

Speaker Series 2016: “Wading Through History: Fossil Hunting Along Rivers Affected by the 2013 Southern Alberta Flood.”

The flooding of several Southern Alberta river systems in 2013 affected hundreds of thousands of Albertans across dozens of communities and caused billions of dollars in damage. A lesser known impact of the floods is that the destructive effect of the water also led to the exposure of many new fossils in the rivers’ banks. The discovery of a complete skeleton of a small dinosaur (known as Leptoceratops) in the flood-ravaged banks of the Oldman River spurred an effort to seek out what other specimens might have been brought to light by the floodwaters. Over the past two years, the Royal Tyrrell Museum of Palaeontology has undertaken a field project to prospect numerous river systems in Southern Alberta to find and collect these newly exposed fossils and protect them from future flooding events.

This presentation showcases the exciting results from the project to date, such as the discovery of several dinosaur trackways from the St. Mary River and a month-long endeavour to recover a Triceratops skull on the Oldman River.

Photo courtesy of Royal Tyrrell Museum and Rich McCrea.

Photo courtesy of Royal Tyrrell Museum and Rich McCrea.

A scientific paper published in Ichnos: An International Journal for Plant and Animal Traces, called “Vertebrate Ichnopathology: Pathologies Inferred from Dinosaur Tracks and Trackways from the Mesozoic”, focuses in-depth on a rarely published component of palaeontology—ichnopathology. Darren Tanke of the Royal Tyrrell Museum assisted nine other authors from Canada, the United States, and China in the benchmark multidisciplinary paper. Ichnopathology is the study of injuries and deformities displayed in fossilized footprints and trackways (a series of footprints). Just like people, dinosaurs suffered injuries from a variety of foot ailments. This study, focussing on carnivorous dinosaur footprints, is the first to examine the types and extent of injuries in great detail.

Some of the specimens from western Canada that were analyzed include a lengthy trackway of an allosauroid with a hip-injury, a footprint of a young tyrannosaur with a severely dislocated toe, and a trackway of an adult tyrannosaur with a missing inner toe. Other specimens included in study are theropod footprints from the Jurassic and Cretaceous periods of western North America and Asia.

The research described the abnormalities by studying the toe impressions, which include examples of swelling, extreme curvature, dislocation, fracture, and amputation.

A number of occurrences were also found in single trackways with significant deformation implying dislocation, fracture, or absence of a single toe. Preserved footprints and trackways demonstrated injuries were not infrequent and that non-life threatening injuries affected their locomotion. For example, 21% of all tyrannosaur prints known at the time of this study showed examples of ichnopathology.

The publication is not available without subscription; however, we are happy to answer any questions pertaining to this research.

Illustraion by Bob Nicholls (c) 2014.

Illustration by Bob Nicholls (c) 2014.

In the scientific community, art serves as a visual source of influential enlightenment, sparking the curiosity of the general public and researchers alike. The palaeoart entitled “Double Death” by Bob Nicholls depicts an exciting contest between two large theropod dinosaurs, Carcharodontosaurus saharicus, fighting over which one will get to eat a medium-sized sauropod dinosaur.

The concept for this picture originally stemmed in the late 1990s when Nicholls watched two birds jointly holding a piece of food. He then translated this idea into a dramatic piece of fleshed out digital art using dinosaurs. The dynamism in the resulting illustration prompted Dr. Donald Henderson, Curator of Dinosaurs, to ask “Could these two theropod dinosaurs REALLY lift a dinosaur almost as big as themselves and not fall over?”

To answer this question, Dr. Henderson conducted a biomechanical analysis using three-dimensional digital models to assess whether a pair of C. saharicus could successfully lift a medium-sized sauropod and not lose balance.

“I calculated how heavy each of the participants were, the two C. saharicus and the sauropod.  I also had to know where their centre of weight was.”

With the body mass and centre of mass determined for the C. saharicus, it turns out that a single animal weighing six tonnes could lift two and a half tonnes and not fall over. This two and a half tonnes represents about 40% of the body weight; however, the limb bones of animals in general can easily experience forces equal to two to three times total body weight when walking or running, so the additional 40% is well within the capacity of the limbs. It would appear that two C. saharicus could, between them, lift a five-tonne dinosaur without difficulty.

This led to two more questions: “Are the neck muscles strong enough to hold up a tonne or two of weight?” and “Are the jaw muscles strong enough to hold up a tonne or two of flesh?”

Estimating the jaw and neck muscle strengths of extinct dinosaurs begins by looking at the sizes of the attachment areas of the various muscles on the fossilized bones. Estimates of the cross-sectional areas of the muscles of interest are then determined. From looking at the muscles in living backboned animals today, we can see that skeletal muscles all have about the same force generating capacity, and the total force is related to the cross-sectional areas of the muscles. Applying these observations and a known muscle tension factor, we can calculate a probable lifting/holding force for the muscles of interest.

The jaws muscles were found to be able to exert sufficient force to hold 512 kg, but the neck muscles would only have been able to support 424 kg. This leads to the neck muscles being the limiting factor, and that two C. saharicus could only lift an animal weighing about 850 kg. The apparent excess capacity of the jaw muscles suggests that a high bite force was important for puncturing and pulling apart large prey items. The large body size of C. saharicus, in comparison to the smaller holding and lifting abilities of the neck and jaws, would have provided a stable, not-easily-toppled platform for manipulating small, struggling prey items.

“The animal ended up being a little bit smaller than the one Bob had done in his illustration, but the basic idea is fine. I just used basic first-year physics to work that out.”

The research conducted by Dr. Henderson was published in the August issue of The Anatomical Record along with the scientific illustration by Bob Nicholls.

“Our ideas have changed, but we still need the artists to bring these things to life, to make them more than just a collection of bones. These were real animals that lived in a real environment.”

Speaker Series 2015: “Messages from Meteorites: The Growth of Planets & the Delivery of Possible Seeds of Life”

While very little evidence is left of Earth’s early days, the highly cratered surfaces of the Moon and Mars indicate that the Earth must have had a very tumultuous past characterized by abundant meteorite impacts. In her talk, Dr. Riches reviews the importance of meteorites in planet formation and the possible role they played, through the transport of water and organic matter, in the origin of life on Earth.

 

 

The Royal Tyrrell Museum’s Speaker Series talks are free and held every Thursday from January to April 2015 at 11:00 a.m. in the Museum auditorium. Please visit the website for more information about upcoming speakers.

Preparation Lab technicians of the Royal Tyrrell Museum of Palaeontology work with fossils as they are made ready for research and display. Doing so takes great patience and care to ensure that specimens are safely handled and prepared, guaranteeing that they will reveal all they have to offer to the scientists who will soon be studying them and the public who will eventually enjoy them on display. Here is a sneak peek of a typical day in the lab.

 

Field jackets and the fossils inside them are regularly moved around the lab to accommodate changes in work assignments and to make room for priority specimens. As often is the case, the specimens are too heavy to lift by hand and the team will use the three-ton overhead hoist to safely move the specimens around the lab. Here, separate field jackets containing the rib cage portion of a Fort McMurray elasmosaur and an Oldman River Leptoceratops are rearranged to make room for additional fossils to be prepared.

Hadrosaurs Book Cover

Hadrosaurs: The Royal Tyrrell Museum International Hadrosaur Symposium

Hadrosaurs were plant-eating dinosaurs and among the most successful species to have ever lived. Also known as duck-billed dinosaurs, they are one of the best-known groups of dinosaurs due to their abundance in the fossil record, notable diversity, and near global distribution in the Late Cretaceous.

In 2011, a collaboration led by Dr. David Eberth and Dr. David Evans between the Royal Tyrrell Museum of Palaeontology and the Royal Ontario Museum brought together an international slate of over 80 scientists and enthusiasts to share their most recent scientific research on duck-billed dinosaurs. The outcome is the publication of the much-anticipated Hadrosaurs, which is the first book to focus entirely on this seminal species and updates our understanding of these “common” dinosaurs. The book shows that, in many ways, hadrosaurs were not so ordinary. The abundance of hadrosaurs in the fossil record has allowed us to learn more about dinosaur palaeobiology and palaeoecology than we have from any other group. The book also names three new kinds of duck-billed dinosaurs (Plesiohadros djadokhtaensis, Adelolophus hutchisoni, and Gongpoquansaurus mazongshanensis).

Dr. David Eberth, Princess Bonebed

Dr. David Eberth, Royal Tyrrell Museum, Princess Bonebed dig site.

Contributing authors propose that the success of duck-billed dinosaurs was likely driven by a combination of factors that included, most importantly, anatomically-unique and functionally-complex jaws and dentitions that processed plants more efficiently than those of any “reptile” before or since. Other unique hadrosaur innovations are explored, such as their communication abilities (involving their crests and a variety of sounds), their herding and group behaviours (including parental care), and their tolerance of many environments (ranging from the Arctic to the Equator), which likely contributed to their resilience.

Written for dinosaur enthusiasts, scientists, and all lovers of dinosaurs, Hadrosaurs is the most up-to-date literature on plant-eating dinosaurs. Secure your copy by emailing the Royal Tyrrell Museum Gift Shop at shop@tyrrellmuseumshop.com.

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