Dinosaurs

PhD graduate finds evidence of respiratory illness in dinosaur fossil: Canadian Press

mattimar — Fri, 11 Feb 2022 21:29:46 +0000

PhD graduate finds evidence of respiratory illness in dinosaur fossil: Canadian Press

mattimar Fri, 02/11/2022 - 16:29

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(Artwork by Corbin Rainbolt)

Topic

Our Community

Alumni

Dinosaurs

Ecology & Evolutionary Biology

Faculty of Arts & Science

Even dinosaurs can catch the flu and experience symptoms like coughing, sore throat, sneezing, high fever and headaches, according to a new study led by ��߲ݴ�ý PhD graduate Cary Woodruff.

Woodruff and a team of researchers identified the first evidence of a respiratory illness in a dinosaur fossil they nicknamed after country singer Dolly Parton, according to a Canadian Press report published in The Globe and Mail. “What we had in Dolly was very consistent with respiratory infections that are found in birds,” Woodruff told the Canadian Press. “It was very, very similar to a respiratory disease that birds get from breathing in fungal spores.”

The fossil contained misshapen structures in the dinosaur’s neck bones, which indicates that the infection traveled from the lungs to the bones. The study was recently published in Scientific Reports.

“If you could hop in that time machine and go back to when Dolly was alive with this infection, you would have very clearly, evidently been able to see that this was a very, very sick animal,” said Woodruff, who believes the infection contributed to the animal’s death.

U of T paleontologist David Evans takes the Globe and Mail on a dinosaur dig

perry.king — Mon, 19 Aug 2019 17:03:33 +0000

U of T paleontologist David Evans takes the Globe and Mail on a dinosaur dig

perry.king Mon, 08/19/2019 - 13:03

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(photo courtesy of David Evans)

Topic

Global Lens

Dinosaurs

Ecology & Evolutionary Biology

Faculty of Arts & Science

Research & Innovation

Royal Ontario Museum

When paleontologist David Evans and his team discovered a triceratops skull in the fossil-rich Hell Creek Formation, the Globe and Mail was right along with them.

Evans, an associate professor at the ��߲ݴ�ý’s department of ecology and evolutionary biology, walked a reporter through his team’s Hell Creek expedition – a five-year project seeking Late Cretaceous period fossils in the mountainous region of Montana. The expedition by the Royal Ontario Museum, where Evans oversees dinosaur research, seeks to enrich fossil data, but also to better understand the circumstances that precipitated the dinosaurs’ mass extinction – including drastic climate change and forced migration.

“Everybody agrees the asteroid impact is what ultimately led to the extinction of the dinosaurs,” Evans told the Globe and Mail.

“What I’m trying to find out is what type of animals made it through the extinction – what kind of circumstances precipitated an ecosystem collapse of that nature and how fast it took for those ecosystems to recover, so we can understand the consequences of what we’re doing today.

“What we’re doing to the planet is happening so fast, we can’t study it and make projections in real time. And we certainly can’t appreciate the long-term effects of what we’re doing to the planet. The fossil record holds important lessons in that regard.”

On eggshells: What the world's oldest eggs reveal about dinosaur evolution

noreen.rasbach — Thu, 14 Mar 2019 17:18:27 +0000

On eggshells: What the world's oldest eggs reveal about dinosaur evolution

noreen.rasbach Thu, 03/14/2019 - 13:18

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Massospondylus eggs (illustration by Julius Csotonyi)

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Research & Innovation

U of T Mississauga

A study of the world’s earliest known dinosaur eggs reveals new information about the evolution of dinosaur reproduction.

An international team of researchers, led by Robert Reisz of the department of biology at the ��߲ݴ�ý Mississauga, studied the fossilized remains of eggs and eggshells discovered at sites in Argentina, China and South Africa – widely separated regions of the supercontinent Pangea.

At 195 million years old, they are the earliest known eggs in the fossil record, and they were all laid by stem sauropods – long-necked herbivores that ranged in size from four to eight metres in length and were the most common and widely spread dinosaurs of their time.

Reisz is puzzled by the fact that “reptile and mammal precursors appear as skeletons in the fossil record starting 316 million years ago, yet we know nothing of their eggs and eggshells until 120 million years later. It’s a great mystery that eggs suddenly show up at this point, but not earlier.”

According to Koen Stein, a post-doctoral researcher at Vrije Universiteit Brussel in Belgium and lead author of the project, the eggs represent a significant step in the evolution of dinosaur reproduction. Spherical, and about the size of a goose egg, these dinosaur eggshells were paper-thin and brittle, much thinner than similar-sized eggs of living birds.

“We know that these early eggs had hard shells because during fossilization they cracked and broke, but the shell pieces retained their original curvature,” Reisz said. (A Diane Scott photo of fossilized Massospondylus eggs and embryos is at left.)

Members of the team, including Edina Prondvai and Jean-Marc Baele, analyzed shell thickness, membrane, mineral content and distribution of pores, looking for clues about why these early eggs might have developed hard shells.

The results of the study show that hard-shelled eggs evolved early in dinosaur evolution, with thickening occurring independently in several groups, but a few million years later other reptiles also developed hard-shelled eggs. One possibility is that hard and eventually thicker shells may have evolved to shield fetal dinosaurs and other reptiles from predators.

“The hard shells would protect the embryos from invertebrates that could burrow into the buried egg nests and destroy them,” Reisz said.

Reisz added that the study raises interesting questions for future investigation. “For example, we would like to understand why dinosaurs and their avian descendants never developed viviparity (live birth) and continued to rely on egg laying, while non dinosaurian reptiles and mammals, including ancient aquatic reptiles, succeeded in evolving this more advanced reproductive strategy.”

The study is co-authored by Reisz, Stein, Prondvai (Universiteit Gent), Timothy Huang (Jilin University), Jean-Marc Baele (Université de Mons) and P. Martin Sander (Universität Bonn) and is published in the journal Scientific Reports. It follows up on earlier research by Reisz, published in 2012, that examined nests of Massospondylus embryos in eggs discovered at nesting sites in South Africa, and a 2013 publication on dinosaur embryology in Lufengosaurus from China.

300 teeth? Duck-billed dinosaurs would have been dentist’s dream

lavende4 — Tue, 16 Aug 2016 14:03:50 +0000

300 teeth? Duck-billed dinosaurs would have been dentist’s dream

lavende4 Tue, 08/16/2016 - 10:03

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Artist depiction of hadrosaurs (image copyright Danielle Dufault)

Elaine Smith

Author legacy

Elaine Smith

Topic

Imagine how much dental care you’d need if you had 300 or more teeth packed together on each side of your mouth.

Duck-billed dinosaurs (hadrosaurs), who lived in the Cretaceous period between 90 million and 65 million years ago, sported this unique dental system, which had never been fully understood until it was examined at the microscopic level through recent research conducted by Aaron LeBlanc, a ��߲ݴ�ý Mississauga PhD candidate; his supervisor, Professor Robert Reisz (��߲ݴ�ý Mississauga vice-dean, graduate), and colleagues at the Royal Ontario Museum and the Museum of the Rockies.

Rather than shedding teeth and replacing them with new ones like other reptiles, hadrosaurs’ mouths contain several parallel stacks of six or more teeth apiece, forming a “highly dynamic network” of teeth that was used to grind and shear tough plant material. Although hadrosaur teeth appear to be fused in place, LeBlanc and his colleagues show that the newest teeth were constantly pushed towards the chewing surface by a complex set of ligaments. When viewed under the microscope, the columns of teeth are not physically touching and are held together by the sand and mud that can get in between the teeth following the decay of the soft ligaments after the animals died.

“Hadrosaur teeth are actually similar to what we have because our teeth are not solidly attached to our jaws. Like us, hadrosaur teeth would have had some fine-scale mobility as they chewed thanks to this ligament system that suspended the teeth in place,” says Reisz.

As they reached the grinding surface, hadrosaur teeth were essentially dead, filled with hard tissue – unlike humans, whose teeth have an inner core filled with blood vessels and nerves.

“Since the teeth were already dead, they could be ground down to little nubbins,” Reisz says.

LeBlanc says this tooth structure – with its tough grinding surface – was “well-adapted to break down tough plant material for digestion,” through both shearing and grinding. This adaptation may have contributed to the hadrosaurs’ longevity and proliferation.

Reisz says that hadrosaurs had “probably the most complex dental system ever made.”

“It’s very elegant – not a single brick of teeth working as a solid unit,” he says. “It’s more like chain mail, providing flexibility as well as strength.”

LeBlanc notes that the duck-billed dinosaur has been known for over 150 years and its dental system has long been recognized as unique, but no one had taken a look inside it at the microscopic level previously. He created thin sections of entire dental assemblies from the upper and lower jaws, that he then ground down, polished and examined under a powerful microscope. Working with their museum colleagues, he and Reisz were also able to explore how hadrosaur teeth form in embryos and hatchlings, providing a more complete picture of this unique model of dental evolution and development.

“The amazing thing is how consistently these dental assemblies conform to our hypothesis of how the system works,” LeBlanc says. “Even in the youngest specimens, the same processes that maintained dental assemblies in the adults were visible.”

The paper, published online in BMC Evolutionary Biology, is part of LeBlanc’s PhD research into the evolution and development of teeth in reptiles and mammals.

This is your chance to see dinosaurs drawn by palaeontology illustrator from famed Reisz Lab

krisha — Wed, 13 Jul 2016 13:41:28 +0000

This is your chance to see dinosaurs drawn by palaeontology illustrator from famed Reisz Lab krisha Wed, 07/13/2016 - 09:41

Blake Eligh

Author legacy

Blake Eligh

Topic

As a child, Diane Scott struggled with reading – until a trip to the Etobicoke Bookmobile revealed that she had been reading the wrong books.

Told to choose anything she wanted, the seven-year-old skipped the standard children’s stories in favour of an illustrated guide to human diseases. The book proved to be the gateway to literacy for Scott. And the combination of science and images helped to set the course for a research career that has spanned nearly four decades.

Since 1979, Scott has worked as a researcher and graphic artist, documenting paleontological discoveries at The Reisz Lab at U of T Mississauga. A retrospective of her illustration work opened in May at Uof T Mississauga in the offices of the Master of Biomedical Communications program.

Exhibit curator and associate professor Dave Mazierski sifted through Scott’s considerable catalogue of work to find examples of her evolving style and unusual specimens.

“Most of the drawings have been published, but if you’re not involved in the research, you probably wouldn’t have seen these images,” Mazierski says, adding that three of Scott's earliest drawings had been taped to a window in the lab. “We wanted more people to see them and be aware that this work is being done here.”

Scott, who has no formal artistic training, earned her bachelor of science degree in 1980 at what was then Erindale College. Beginning as an undergraduate summer student, Scott soon demonstrated her unique talents for detailed technical work and accurate observational drawings.

“In this field, there are people who are artists and there are people who are technical preparators, but there’s only one Diane, who does both,” says renowned biology professor and long-time collaborator Robert Reisz. “I don’t know of anybody else who does what she does.”

As a lab technician, fossil preparator and scientific illustrator, Scott is an anomaly. “I take the project from the beginning—I prep it, figure it out, draw it and reconstruct it,” she says. “I’m not a PhD or a post-doc. It’s very unusual for someone with my background to be allowed to do the things I do.”

Scott and Reisz have worked together for 37 years in what both describe as a true partnership. Scott has dozens of publications and hundreds of citations to her credit. “It’s a scientific conversation between Diane and myself,” Reisz says. “When I have a perspective, I have to prove it to her and she challenges me constantly. I drive the research, but Diane is the one who executes and carries forward the work.”

Scott receives specimens from around the world, and often doesn’t know what she’s got until the preparatory work is completed. She uses a small pneumatic tool to chip away layers of sediment and reveal the fossil underneath. It’s painstaking work – Scott won’t work with anyone else in the room for fear of vibrations. She once spent six months slowly uncovering a clutch of small Massospondylus eggs and embryos trapped in rock. “The eggshell was thin as two pieces of paper and the embryonic bone was so fine that when you wet it, it disappeared,” she remembers. Over the years, she has developed a kind of sixth sense about what may lie beneath layers of sediment. “You almost get a sense of where the bones are,” she says. “It’s a fine line. You have to know when to stop.”

Once the specimen is prepared, Scott uses micromeasurements and her vast knowledge to reconstruct what the animal might have looked like. “You have to figure out where one bone stops and another begins. You have to look for clues to help identify what kind of an animal it is. Sometimes, it’s something new that we haven’t seen before,” she says. ”There’s no easy way of doing it.”

Scott then draws the specimen. In the early days, she used a camera lucida to create precise renderings of what she saw. Part drawing aid, part optical illusion, the camera lucida is a device that reflects the image of an object through a prism, allowing the artist to see the object and the drawing surface at the same time. Peering into the camera, Scott used a fine stippling technique, something she likens to drafting, to ensure clear reproductions. The camera lucida has been replaced by a scanning electron microscope and Photoshop software, but Scott still draws by hand. She uses Coquille board, a paper with a pebbled texture that picks up soft wax and graphite conté pencil to create the stippled effect so necessary for print reproduction. “It’s unforgiving and impossible to erase, but I love it because it’s artistic,” Scott says. With three decades of practice, she doesn’t often make mistakes.

“As an illustrator, I’ve been impressed with how remarkable and beautiful these drawings are,” Mazierski says. “You can see from one to the next how Diane’s technique has evolved. It’s lighter in tone and more precise and more refined.”

“She plays with light and the forms that light and shadow create to make the drawing clear, but she bends the rules where it suits her,” Mazierski continues. “She’s most concerned about the form.”

Scott’s enthusiasm for her work is infectious. She describes the Massospondylus eggs as “the cutest things!” and has a soft spot for a small, beaked hippo-like creature called a Dicynodont. “If this thing existed now, it would be the number one pet,” she says.

“I never had to grow up,” Scott says. “I’m always learning. I’m never bored. I always liked art and I liked science and I get to do both every day.”

Visitors can view the exhibit from Monday to Friday between 8:30 and 4:30 in the Biomedical Communications hallway on the third floor of the Health Sciences Complex at the ��߲ݴ�ý Mississauga until September 30, 2016.

Did dinosaurs have lips? Ask this ��߲ݴ�ý paleontologist

lanthierj — Thu, 19 May 2016 20:08:17 +0000

Did dinosaurs have lips? Ask this ��߲ݴ�ý paleontologist

lanthierj Thu, 05/19/2016 - 16:08

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Artist interpretation shows 190-million-year-old nests, eggs, hatchlings and adults of the prosauropod dinosaur Massospondylus in Golden Gate Highlands National Park, South Africa (image credit: Julius Csotonyi)

Blake Eligh

Author legacy

Blake Eligh

Topic

Subheadline

“In popular culture, we imagine dinosaurs as more ferocious-looking, but that is not the case”

Can a crocodile’s smile reveal whether dinosaurs had lips? What if lips and gums hid most of dinosaur's teeth?

New findings from ��߲ݴ�ý vertebrate palaeontologist Robert Reisz challenge the idea of what therapods might have looked like when dinosaurs roamed the earth.

His research will be presented today at a conference at U of T Mississauga – and it's already making headlines.

Read the Globe and Mail story

Read the Vice story

Read the BBC story

Read the Guardian story

“When we see dinosaurs in popular culture, such as in the movie Jurassic Park, we see them depicted with big teeth sticking out of their mouths,” Reisz says. Large dinosaurs, such as Tyrannosaurus rex, bare a ferocious grin, while smaller creatures such as velociraptors are shown with scaly lips covering their teeth.

The U of T Mississauga expert was curious about which version might be most accurate. “We have very little information about dinosaurs’ soft tissue,” he says.

For clues about how therapods might have appeared, he looked to modern-day reptilian predators like crocodiles and monitor lizards. According to Reisz, lipless crocodiles have exposed teeth, much like a Jurassic Park predator, while monitor lizards conceal teeth behind scaly lips that are similar to the movie version of velociraptors.

Lips help to protect teeth, in part by helping to enclose them in a moist environment where they won’t dry out, Reisz says. Crocodiles, which spend their time submerged in water, don’t need lips for protection. “Their teeth are kept hydrated by an aquatic environment,” Reisz says.

Reptiles with lips, such as monitor lizards, typically live on land (much like their movie counterparts) where their teeth require different protection. From this, Reisz concludes that dinosaur teeth would likely have been covered by scaly lips.

“It’s also important to remember that teeth would have been partially covered by gums. If we look at where the enamel stops, we can see that a substantial portion of the teeth would be hidden in the gums. The teeth would have appeared much smaller on a living animal.

“In popular culture, we imagine dinosaurs as more ferocious-looking, but that is not the case.”

(Below: Gorgosaurus using its specialized teeth for feeding on a young Corythosaurus/image credit: Danielle Default)

Reisz presents his findings on May 20 at the annual meeting of the Canadian Society of Vertebrate Palaeontolgy at UTM. The two-day conference, which began on May 19, brings together 60 Canadian researchers working in Canada and around the globe.

“Canada has some very significant locations for understanding vertebrate evolution, ranging from the late Cretaceous in Alberta to the Pleistocene in the Arctic and the early stages of terrestrial vertebrate evolution in the Atlantic region,” says Reisz, who helped to organized the conference.

“There are about 1,000 people worldwide who study vertebrate fossils. It’s important to come together and exchange ideas and unite a community that is so widespread geographically.”

The conference features presentations on the latest research in palaeontology, including a crocodile-like creature from Sudan discovered by U of T researcher David Evans; a talk on the evolution of how birds hear; what a recently discovered ceratops from Montana tells us about horned dinosaurs; and deciphering the social behaviour of oviraptorsaurs found in Mongolia.

Dinosaurs

PhD graduate finds evidence of respiratory illness in dinosaur fossil: Canadian Press

U of T paleontologist David Evans takes the Globe and Mail on a dinosaur dig

Read more about David Evans in the Globe and Mail

On eggshells: What the world's oldest eggs reveal about dinosaur evolution

300 teeth? Duck-billed dinosaurs would have been dentist’s dream

This is your chance to see dinosaurs drawn by palaeontology illustrator from famed Reisz Lab

Did dinosaurs have lips? Ask this ��߲ݴ�ý paleontologist

Read the Globe and Mail story

Read the Vice story

Read the BBC story

Read the Guardian story

See the complete schedule

Dinosaurs

PhD graduate finds evidence of respiratory illness in dinosaur fossil: Canadian Press

U of T paleontologist David Evans takes the Globe and Mail on a dinosaur dig

Read more about David Evans in the Globe and Mail

On eggshells: What the world's oldest eggs reveal about dinosaur evolution

300 teeth? Duck-billed dinosaurs would have been dentist’s dream

This is your chance to see dinosaurs drawn by palaeontology illustrator from famed Reisz Lab

Did dinosaurs have lips? Ask this ���߲ݴ�ý paleontologist

Read the Globe and Mail story

Read the Vice story

Read the BBC story

Read the Guardian story

See the complete schedule

Did dinosaurs have lips? Ask this ��߲ݴ�ý paleontologist