Casey Holliday

Where the decolonizers (colonizers??? ;) ) spell Paleo incorrectly and the women spell paleo correctly. Yay women! Sorry Marc, wish I was there and we could hang.

Calling Midwest Anatomists and Paleontologists!
Deadlines Extended! Sept 1st for Talks and Posters! Sept 12th for registration. Look forward to seeing you here! @anatomyorg.bsky.social @paleosoc.bsky.social @societyofvertpaleo.bsky.social

www.anatomy.org/.../Meetings...

Congratulations to Emma Cooney on graduating with a MS out of the lab. Stay tuned for some wicked cranial
morphology.

Happy to meet new people and share our work on imaging and informatics at @bionexuskc.bsky.social in Kansas City.

Good times with good people at AAA this week!

AAA fellows

Congratulations to our 2025 Class of Fellows! They were recognized at the Fellows reception tonight and received their AAA Fellows pin!🫀🧠

#Anatomy25 #anatomy #education #research #science #aaa #portlandoregon #scientificmeeting #annualmeeting

Is a bone a viable weapon when combating a Rancor? Estimating the bite force of an intergalactic mega-predator Stephan Lautenschlager1,2 & Thomas Clements3 1School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK. 2The Lapworth Museum of Geology, Birmingham, UK. 3…

This project has started a long time ago, but in a galaxy not too far away… Happy to share this new study with @taphonomist.bsky.social looking at the functional morphology and biomechanics of the Rancor. Warning! Nerdy sci fi, palaeo & biomechanics thread following! jgeekstudies.org/2025/03/08/i...

A 6 panel figure from this paper. On the left are photos of a cormorant, lorikeet, kingfisher, and songbird scratching their heads with one foot. On the right are two different phylogenetic trees of avian orders with head scratching pattern (underwing or overwing) mapped on top.

New paper out today!

Here we examine how a simple behaviour, head scratching, has evolved in birds. There are some relatively complex changes going on that vary across clades, as demonstrated by @gallinaciega.bsky.social analyses.
www.frontiersin.org/journals/eth...
#birds #ornithology #evolution 🪶

If you’re hanging out at the 5th Palaelontolgical Virtual Congress, and you like crocs (or even not!) visit my talk here and join the comments! www.palaeovc.org/6/great-tran...

Cool photos!!!
Video of one of them fyi: www.instagram.com/reel/DHUdTyu...

Hey welcome to Bluesky @alec-wilken.bsky.social

Hey welcome to Bluesky @alec-wilken.bsky.social

This means that the temporal muscles of birds are more fore-aft oriented compared to the more vertical muscles of their dinosaur ancestors. This shows a change in feeding behaviors, from bitey, stiff skulls of early dinosaurs to dexterous, flexible-headed birds. Art by Corrine Cranor.

Meanwhile, we also project these vectors as ternary plots to get a general sense of orientation change. In general, you might see how many temporal muscle dots start at the top of the plot in Allosaurus and then plinko their way down along the RC (rostrocaudal) axis along the line to birds.

Meet our vector bouquets: orientations and magnitudes of jaw muscles projected as colored vectors and here plotted from a common origin on a single taxon, Dromaeosaurus, to show a phylogenetic change in muscle orientation.

The supplementary info hosts a number of plates documenting the muscle attachment sites we used to model jaw muscles. The centroids of each of these surfaces were used to estimate orientation vectors while the we also used them to model volumes which were used in estimating muscle forces.

Dinosaur Jaw Muscle Evolution - A 3D model collection by Holliday Lab (@holliday) This collection shares 3D models of skulls and jaw muscle resultant vectors demonstrating phylogenetic changes in muscle orientation along the lines to modern birds. While temporal muscles shifted to ...

Accompanying our recent paper documenting evolutionary changes in jaw muscles along the line to birds, is a collection of models on Sketchfab illustrating 3D resultant vectors of jaw muscles along with skulls and a few different ways of visualizing data like these. (www.pnas.org/doi/10.1073/...

Big ups to the group, particularly Alec Wilken and Kaleb Sellers for cooking up some simple yet elegant comparative approaches for exploring musculoskeletal biomechanics. Thanks to museum collections and colleagues for making specimens and their data available. Funding is thanks to #NSF.

Some birds use their protractor muscles to actively power cranial kinesis, but inferring this function in fossils is challenging. We compared 3D resultants of protractor muscles to orientations predicted palatal movement and found the muscles weren’t optimized for powering kinesis until Neognaths.

Compared to even their Cretaceous ancestors, living birds have fewer struts and linkages in their skulls, resulting in a higher potential for cranial kinesis, the ability of birds to move multiple joints in their skulls. Think about how a parrot can use its upper beak as an extra limb.

We reviewed palatal morphologies across a variety of Mesozoic birds. Many changes the palate occurred, namely the breakdown of linkages between the quadrate, epipterygoid and braincase. Much of this change maybe be hidden in the developmental biology of the palatoquadrate cartilage.

We figured out how to calculate 3D resultant vectors of jaw muscles in a modeled sample of living and extinct dinosaurs and found that a number of muscles change orientations and proportions as the brain got big and changed head shape during the origin of birds.

🧪

How big brains and flexible skulls led to the evolution of modern birds 3D modeling shows how larger brains triggered changes in jaw muscles and joint mechanics that powered a flexible feeding system for modern birds.

biologicalsciences.uchicago.edu/news/bird-sk...

Happy to share this new paper! We explored the relationships of head shape and feeding mechanics in dinosaurs. A cascade of changes from big brains, to reoriented muscles, to a breakdown of linkages resulted in avian powered kinesis, but not until neognathes.

www.pnas.org/doi/10.1073/...

Movers and shakers in the lab: Chris, Aryan, Corrine, John, Cerise and whiteboard.

My Obituary of Elisabeth Vrba—out today in Nature in read-only format:

rdcu.be/ediyO

Catch my talk at #5thPVC! Thanks for the invite! Psst… it’s on croc heads.

Awesome, for funky socks Monday I will cease washing my intended socks now. Now to get those steps in!