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Reposted by Christiana Garros

Jay @kakapojay.bsky.social · Jul 2

The final portrait I could find from my time on WWD - Rose the Albertosaurus. All of these were done in early 2024, so about a year and a half ago now!

#sciart #paleoart

A portrait of Albertosaurus as seen on Walking with Dinosaurs 2025.

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Reposted by Christiana Garros

Marcos K. Pinheiro / "Marcos Wyvern" (Marcosaurus) @mmarcosaurus.bsky.social · Jun 20

#WWD2025
How Extreme Weather Can Reveal (And Destroy) Dinosaur Fossils | #WalkingWithDinosaurs Unearthed
With Mark Powers, Henry Sharpe and the whole team including Christiana Garros ( @chrissygarros.bsky.social)
By PBS Terra
www.youtube.com/watch?v=jtpJ...

How Extreme Weather Can Reveal (And Destroy) Dinosaur Fossils | Walking with Dinosaurs Unearthed

YouTube video by PBS Terra

www.youtube.com

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Reposted by Christiana Garros

Marcos K. Pinheiro / "Marcos Wyvern" (Marcosaurus) @mmarcosaurus.bsky.social · Jun 18

#WWD2025
Student-led crew brings Albertosaurus named Rose to the screen #WalkingWithDinosaurs
With Mark Powers, Annie McIntosh, Colton Coppock, Henry Sharpe, Christiana Garros (@chrissygarros.bsky.social) and Jordan Stock mentioned
www.ualberta.ca/en/folio/202...

Student-led crew brings Albertosaurus named Rose to the screen

The second season of BBC’s hit Walking With Dinosaurs features a team of U of A graduate students helping excavate an Albertosaurus and bring it to life on screen.

www.ualberta.ca

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Christiana Garros @chrissygarros.bsky.social · Jun 13

#livefromthefield
Work resumes on "Scorpio" the Lambeosaurus lambei whose quarry was reopened last year. While last year we collected the skull, this year the body blocks are revealing vast swaths of skin underneath! Exciting!

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Christiana Garros @chrissygarros.bsky.social · May 26

Dinosaur park my beloved. Excited to be back there in 2 weeks 🥰
For such a rich formation, big beautiful mural-style pieces like this one are not as common as I would like!

Joschua Knüppe @joschuaknuppe.bsky.social · May 25

Result from the Dinosaur Park Formation #paleostream! This formation was on the wheel from the start and I anticipated and dreaded it at the same time. As one of the most famous dinosaur bearing formations this piece offered several challenges.

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Christiana Garros @chrissygarros.bsky.social · May 19

For those itching to know more about what you might expect to see each episode!
www.bbc.co.uk/mediacentre/...

Walking With Dinosaurs - Everything you need to know about the ground-breaking series

Discover the incredible life stories of more long-lost giants as the landmark series returns

www.bbc.co.uk

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Christiana Garros @chrissygarros.bsky.social · May 4

☺️♥️

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Christiana Garros @chrissygarros.bsky.social · Apr 27

Yep! You are! You're only the second person I've seen who noticed it!

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Christiana Garros @chrissygarros.bsky.social · Apr 21

Overall, I am very happy with this project. I would like to sincerely thank my coauthors and many mentors and friends I've made along the way. I would also like to thank the guest editors of the special issue Mateusz Wosik and @funstonpaleo.bsky.social . I am excited to see the full thing!

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Christiana Garros @chrissygarros.bsky.social · Apr 21

It is worth noting however, that histological markers can vary a lot across the skeleton of an individual, so approach direct comparisons with other individuals and elements with caution. Always consider histological studies in the context of which bones were sampled and where

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Christiana Garros @chrissygarros.bsky.social · Apr 21

What this could mean we have no idea. Sexual dimorphism with different ages of reaching sexual maturity? Different taxa entirely with different growth trajectories? Something else? A Regardless, we found it extremely interesting and definitely something worth exploring

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Christiana Garros @chrissygarros.bsky.social · Apr 21

Stranger however, is that there appear to be two growth trajectories present even among the healthy individuals. One with an earlier growth spurt and plateau (blue, red, orange?), and another with a later one (teal, black, green)

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Christiana Garros @chrissygarros.bsky.social · Apr 21

We were curious how, (if at all), these pathologies impacted growth in these animals, so we measured area within cyclical growth marks. While it appears TMP1992.036.0720 (red) may have experienced reduced growth, the other two (black and teal) seem relatively unaffected

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Christiana Garros @chrissygarros.bsky.social · Apr 21

Unlike the other two specimens, the trauma in this one appeared to have happened earlier in life and was more widely impacting. Severe resorption at the distal end suggests chronic inflammation at the distal joint that may have resulted in lameness and subsequent injuries

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Christiana Garros @chrissygarros.bsky.social · Apr 21

The third specimen however, was a little bit more complicated. TMP1992.036.0720 consisted of a severely deformed MTIV (pictured here) and a slightly deformed MTII

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Christiana Garros @chrissygarros.bsky.social · Apr 21

Speaking of stress, we selected three pathologic specimens we deemed good candidates for histology. Two of these appear to have relatively straightforward conditions. A superficial cortical fracture, and an enthesophyte turned chip fracture in another.

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Christiana Garros @chrissygarros.bsky.social · Apr 21

By taking full cross-sections and sampling across the entire metatarsus, we were able to map where along the metatarsus different bone types occur, which parts grow and finish growing first, and where the stresses concentrate (as shown by Haversian bone)

Figure 1 from the paper. Featuring an illustration of a troodontid foot with lines indicating where the sections were taken. On the right, there are illustrations of the histologic thin sections taken across the foot showing where different bone types deposit

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Christiana Garros @chrissygarros.bsky.social · Apr 21

Fortunately, metatarsals are among the most commonly found and recognized isolated troodontid elements from the Dinosaur Park Formation, and this combined with the generosity of the lovely folks at the Royal Tyrrell, allowed us to section 11 specimens!

A box containing 11 troodontid metatarsals after they have been sectioned. Specimens are in several pieces with some being embedded in resin

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Christiana Garros @chrissygarros.bsky.social · Apr 21

So we set forth to sample as many metatarsals as we could in hopes of not only exploring the growth of troodontids from the DPF (which had never been done prior) but also to diagnose pathologies we found and see how they related to the animal's life stage or impacted growth.

A block of resin containing the distal portion of a troodontid left metatarsal II, a slide with a thin section of the same metatarsal II, and another block of resin containing a small piece of the shaft that was removed when the section was made.

Four histology thin section slides of the midshaft region of troodontid right metatarsal IVs

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Christiana Garros @chrissygarros.bsky.social · Apr 21

My lovely colleagues Mark Powers and @a-dyer-wolf.bsky.social introduced me to the world of histology, and how it can be used not just to help diagnose pathologies like the one above, but also explore the life history of these animals (the first section we made shown here)

A transverse histologic section of the shaft of a troodontid left metatarsal II

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Christiana Garros @chrissygarros.bsky.social · Apr 21

At the 2022 SVP meeting, I presented the preliminary findings of my metatarsal pathology survey, among which was an unusually high occurrence of pathologies in troodontids. This paired with their weird anatomy, was hard to ignore, so I decided this taxon warranted a closer look

Me standing next to my poster that I presented at the 2022 SVP annual meeting in Toronto

5 pie charts showing pathology prevalence from a survey of theropod metatarsals. Each chart is a taxon (Caenagnathidae, Dromaeosauridae, Ornithomimidae, Troodontidae, and Tyrannosauridae). Tyrannosaurs had 50% pathologic specimens, troodontids had about 1/3

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Christiana Garros @chrissygarros.bsky.social · Apr 21

In particular, I became fascinated with the troodontids and their unusual modified arctometarsus (pictured on the right), which features an enlarged MTIV and reduced, laterally compressed MTII for bearing the raptorial digit.

Illustrations of the foot of an ornithomimid, tyrannosaur, and troodontid. The metatarsals are highlighted. Yellow for MTIV, green for MTIII, and teal for MTII. Icons from phylopic of the taxa are present above the foot illustrations

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Christiana Garros @chrissygarros.bsky.social · Apr 21

In 2019, I begun my histology and pathology journey at the Royal Tyrrell Museum surveying theropod metatarsals for signs of injury and disease. I was interested in theropod feet because of their similarity to those of birds, and metatarsals because of their varied morphologies

Me sitting at a table at the Royal Tyrrell Museum collections with my laptop and several theropod metatarsal specimens on the table

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Christiana Garros @chrissygarros.bsky.social · Apr 21

Paper here, thread following
onlinelibrary.wiley.com/doi/10.1111/...

Osteohistological analysis of metatarsals reveals new information on pathology and life history of troodontids from the Campanian Dinosaur Park Formation, Alberta, Canada

A histological survey of troodontid metatarsals from the Dinosaur Park Formation (DPF) was conducted, revealing correlates for stresses in the troodontid arctometatarsus and providing the first histo....

onlinelibrary.wiley.com

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Christiana Garros @chrissygarros.bsky.social · Apr 21

Published yesterday in @journalofanatomy.bsky.social with open access, we demonstrate how tiny slices of isolated bones (in this case, troodontid metatarsals) can provide a wealth of information on the growth, lifestyle, and injuries of these animals. (🧵) (Troodontid art by Henry Sharpe )

A troodontid with a pathologic metatarsal Iifts its foot towards its face to investigate. The pathologic bone is highlighted and features a red line to indicate where a thin section was taken. The thin section appears as aarge imags behind the troodontid, the troodontid's tail passing through the central medullary cavity.

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