Tim Demko

A dinosaur that is new to science has features of both subfamilies of the tyrannosaur group, complicating our understanding of how they evolved

Um novo dinossauro iguanodonte da Formação Weald Clay (Cretáceo Inferior) de Smokejacks Brickworks, sul da Inglaterra www.tandfonline.com/doi/full/10....

The Rhynie chert Lagerstätte – An Early Devonian hot-spring ecosystem frozen in time link.springer.com/article/10.1...

Aww, crap ... it's #MolluskMonday and I haven't posted anything yet 😅 So, howzabout everyone's favorite poly/enby sequential hermaphroditic snail, the slipper shell Crepidula? 🧪⚒️🐚

Di, Z., Wang, H., Wang, T. et al. An Early Jurassic soft eggshell provides insights into the evolutionary history of dinosaur eggs. Nat Commun (2026). doi.org/10.1038/s414...

Young et al have an interesting paper out, demonstrating that the Laurentide Ice Sheet started to advance between 2000 and 1000 years ago, possibly heralding the inception of the next glacial cycle. However, due to rising CO₂, the advance stopped in the 1960s. www.science.org/doi/full/10....

Countdown until people realize that the new NSF Office of Metascience will be used to bludgeon the sciences, thereby revealing the fascist undertones of much of metascience

A newly identified fossil amphibian, measuring 737 millimetres in length and dating back around 237 million years, may have been fully adapted to life in the sea, according to a study in Nature Ecology & Evolution. go.nature.com/4iiWdep #Paleosky #evosky 🧪

New, comprehensive study on the skeletal anatomy of Dialipina salgueroensis. Pretty compelling anatomy here supporting a position outside the osteichthyan crown group, which implies relatively late survivorship of this otherwise Silurian clade cdnsciencepub.com/doi/abs/10.1...

When I saw those reviewer comments and said "wow, this guy is clueless; I wish he never even read my paper," this isn't what I meant.

Evolutionary 'game-changer': weird armoured amphibian lived in ancient seas www.nature.com/articles/d41...

Cactuses make a surprisingly large amount of carbonate when they die. Makes the desert strangely coral reef like.

During the last Ice Age, a vast ice shelf helped hold back the Greenland and neighbouring ice sheets. When it collapsed, rapid retreat followed. Sound familiar? 👀

A beautiful stem for this late #FossilFriday. This relative of today's horsetails was growing a little over 300 million years ago in what is now Kansas 🌿⛏️ #paleobotany #botany

The old Theia is dead, a new Moon struggles to be born. Now is the time of monsters. . . er, new models for the formation of our Moon. Adeene Denton (@spacewhalerider.com) and colleagues showed a way to smooth the process of Moon formation. 🔭🧪 eos.org/articles/was...

Sharing one of my favourite phenomena for #FossilFriday: when a drill core bullseyes a fossil! This one, from the Silurian of Estonia, has caught some exceptionally preserved body segments of a pterygotid eurypterid. ⚒️🧪

Salt marshes protect coastlines by attenuating wind waves, but even though the marsh substrate remains stable during extreme storms, vegetation damage reduces wave attenuation. Nature can only do so much to protect us against an increasingly dangerous world created by climate change. 🌊🧪

Our latest: Reconstructing spore evolution recalibrates the timescale of land plant diversification, led by Jack Hooper, Annie Worth, with help from Charles Wellman @jameswclark.bsky.social and myself. file:///Users/glpcjd/Downloads/s41477-026-02432-3.pdf

Also: Martin Ezcurra and Diego Pol in their natural environments

Fall semester is when I teach our Sed-strat course for Earth and Environmental Science majors. They’ve had classes in mineralogy, field methods, structure, and ig-met, but haven’t measured stratigraphic sections yet. It’s typically a learning curve but rewarding and fun. ⚒️

Why are this group of sedimentologists smiling and happy? Because they are in beautiful Rock Island State Park in Tennessee with its incredible waterfalls? Yes, but more so because of the world-class exposures of giant sediment waves in the Mississippian Fort Payne Limestone!

Apply for my old job!

🚨Jobs Alert 🚨‼️ Multiple #geology positions with the US Bureau of Land Management. Including Nevada, Arizona, Colorado, Wyoming, Oregon, Winnemucca, Nevada ⚒️ www.usajobs.gov/job/889070100 www.usajobs.gov/job/889068800

✨ New paper ✨ on subsurface ocean warming in both N and S hemispheres during the early deglaciation! 🌊 I am incredibly proud of this work, which is led by my former graduate student, Cassie Stirpe. www.nature.com/articles/s43...

A remarkable sample of bird teeth from the palaeo-Arctic Prince Creek Formation of northern Alaska elucidates Late Cretaceous avialan richness royalsocietypublishing.org/rsos/article...

Happy to share our new Science Advances @science.org paper on ~250 Myr of crocodile-line archosaur macroevolution and climate! 🐊☄️ #croctober 🔗 www.science.org/doi/10.1126/... Artwork: Davide Bonadonna 🧵 1/6

Have you ever seen a rock that is composed almost entirely of foraminifera? Now you have! From a Late Pleistocene (probably MIS 3/4) outcrop in western Kikaijima, Japan.

If I had a nickel for every paleontologist with a pachycephalosaur tattoo posing with a pachycephalosaur fossil, I’d have two nickels. Which isn't a lot, but it's weird that it happened twice. Here's Sally Hurst & I at the MIP posing with a HUGE and new specimen of Prenocephale we're working on.

I spent most of last week in Death Valley National Park. Here are some photos

Every future scientist kid wants to have a paper about dinosaurs. Here I go ✅ with this in @natrevbiodiv.nature.com with @tweetisaurus.bsky.social, @richardjbutler.bsky.social and T Matthews. We asked - how to study islands in the fossil record? Turns out - with great difficulty! @leverhulme.ac.uk

Happy #MosasaurMonday from Walker, the first Mosasaurus I ever completely restored from Kansas From the Weskan Formation, it is the earliest member of the genus. This cast copy now resides in Japan, 28 feet long and full of teeth

Looking through some older photos and came across some sedimentological gems. Lunate ripples in the Turkwel River, Turkana, Kenya. The ripples were dissected during falling stage and draped with mud. Internal cross-laminae are now exposed. Bonus trough cross-beds from nearby Miocene rocks. ⚒️

For #FossilFriday, a sampler from yesterday's sarcopterygian lab for EARTH 437: Vertebrate Paleontology. First off, the onychodont station featuring material of Onychodus from the Middle Devonian of Ohio.

Pavement geology in Sweden: Ordovician Orthoceras in Gothenburg train station.

#FossilFriday Gertrude Lilian Elles (1872-1960)was a field geologist, stratigrapher and palaeontologist. In 1919 she won the Murchison Medal and became one of the first female Fellows of the Geological Society 🧪⚒️ #FeministFriday #WomenInSTEM paleonerdish.wordpress.com/2016/10/19/f...

Katie was fired so fast the equation needs a rounding error.

Satellite images of the Panama earthquake show that the fault slipped up to 7 meters. That a lot! With that much slip, a two-lane road crossing the fault would be completely offset. This is a pretty remote area, so not so many roads, but field photos will surely be impressive. ⚒️ 🧪

NEW PALEO JOB!! The Evolutionary Studies Institute (ESI) in Johannesburg is hiring a Director. Famous for human origins, dinosaur evolution, and most importantly (😅) Permo-Triassic tetrapods, this is a huge opportunity to lead one of the world’s greatest paleo institutes. Please share!

Evolution of inner ear shape in birds and other theropods (as well as pterosaurs) relates more to braincase geometry than the ability to fly: www.pnas.org/doi/10.1073/... 🪶🧪 (📷 @gnavalon.bsky.social et al.)

Okotoks Erratic – ‘Big Rock’ located just outside the town of Okotoks Alberta. This is a massive block of quartzite transported a few hundred km’s from its source near Jasper.