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Reposted by Milo Gaillard

🎃 Spooky Kia 🎃 🏳️‍🌈 Chaotic Whovian of Arrakis @yutytyrant.bsky.social · 2h

🦖 Daily Paleo 🦖; Brontotholus harmoni

From Late Cretaceous Two Medicine Formation, USA, "Thunder Dome" (Ace name!) is a newly described pachycephalosaur and the 3rd largest known. It's not closely related to either Stegoceras nor Pachycephalosaurus, suggesting more diversity

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Milo Gaillard @milogaillard2.bsky.social · 7h

Let me guess, Nanotyrannus prompted you to write this mini thread. Am I right?

Reposted by Milo Gaillard

SpinoInWonderland @spinoinwonderland.bsky.social · 13h

Nearly six years ago, I wrote a blog post on how many dinosaur species probably existed in the Mesozoic.

thesauropodomorphlair.wordpress.com/2019/12/29/h...

It had also led me to be much less trusting of taken-for-granted species-level taxonomic lumping. We had even overlumped modern birds.

How many Mesozoic dinosaur species were there?

How many dinosaur species where there? More precisely, how many dinosaur species from the Mesozoic Era were there? This specifier excludes the Cenozoic forms (which are all birds), as they generall…

thesauropodomorphlair.wordpress.com

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Reposted by Milo Gaillard

PaleoJim @paleojim.bsky.social · 2d

A newly minted name for Utah's largest dinosaur, Utetitan! Given the amount of time these latest Cret sauropods span, more than one taxon likely. I did not review this manuscript, so let the sauropod researchers weigh in.
giw.utahgeology.org/giw/index.ph...
@paleontologizing.bsky.social

Stratigraphic and anatomical evidence for multiple titanosaurid dinosaur taxa in the Late Cretaceous (Campanian-Maastrichtian) of southwestern North America | Geology of the Intermountain We...

giw.utahgeology.org

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Reposted by Milo Gaillard

PaleoJim @paleojim.bsky.social · 20h

Great new paper by Mannion & Moore 2025 on diplodocoid sauropods for #FossilFriday I love their latest phylogeny as it certainly supports the mass extinction of sauropods at the end of the Jurassic that is so well documented in eastern Utah. www.tandfonline.com/doi/epdf/10....

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Reposted by Milo Gaillard

PaleoGalli @paleogalli.bsky.social · 23h

Reavaliação crítica de um suposto dinossauro saurópode dicreossaurídeo do Jurássico Médio de Gondwana e uma visão revisada dos relacionamentos evolutivos e biogeografia dos diplodocóides www.tandfonline.com/doi/full/10....

Critical reappraisal of a putative dicraeosaurid sauropod dinosaur from the Middle Jurassic of Gondwana and a revised view of diplodocoid evolutionary relationships and biogeography

Diplodocoidea is a diverse clade of sauropod dinosaurs that comprises three major lineages: Diplodocidae, Dicraeosauridae and Rebbachisauridae, with the former two united as Flagellicaudata. There ...

www.tandfonline.com

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Reposted by Milo Gaillard

Museum of the Rockies @museumoftherockies.bsky.social · 23h

Happy #FossilFriday! Meet Brontotholus harmoni (MOR 480), a new pachycephalosaurid from the Cretaceous Two Medicine Formation of Montana. Named after former MOR Chief Preparator Bob Harmon. Bronotoholus was named this week in a @ZoolJLinnSoc paper by MSU alumnus @doublebeam and colleagues.

Fossilized dome of Brontotholus harmoni, a large pachycephalosaurid dinosaur from the Cretaceous Two Medicine Formation of Montana, showing its rounded, textured skull surface displayed against a dark background.

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Reposted by Milo Gaillard

Mesozoic Market | Fossil Collector & Amateur Paleontology @mesozoic.bsky.social · 1d

A fossilized osteoderm from a Cretaceous aged softshelled turtle, possibly Khunnuchelys kizylkumensis from the Bissekty Formation in Dzharakuduk, Kyzylkum Desert, Uzbekistan. Other species of this genus also occur in China and Kazakhstan. #FossilFriday

#turtle #fossil #paleontology #khunnuchelys

Fossilized softshelled turtle osteoderm or scute of a Khunnuchelys.

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Reposted by Milo Gaillard

American Museum of Natural History @amnh.org · 1d

It’s Fossil Friday! This archival image, snapped in 1966, depicts Museum visitors gazing up at the mounted remains of Gorgosaurus. This slender tyrannosaur was smaller than its gigantic cousin T. rex, reaching lengths of up to 30 ft (9 m) and weights of 2,200 lbs (1,000 kg).

A photo of two Museum visitors gazing up at a mounted Gorgosaurus. The animal’s bones are posed on its hind legs, standing straight up with its tail dragging behind it. The Museum visitors’ backs are turned, facing the dinosaur.

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Milo Gaillard @milogaillard2.bsky.social · 1d

Unfortunately, for as much prehistoric fauna that there is in California (e.g., La Brea Tar Pits, and many marine animals), not many non-avian dinosaurs have been described, due to their poor preservation in the state. I hope Mesozoic dinosaur paleontology improves here. 2/2

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Milo Gaillard @milogaillard2.bsky.social · 1d

#FossilFriday I decided to try bring awareness to a dinosaur from where I live: California. Enter Augustynolophus morrisi. Discovered in the Moreno Formation, this hadrosaur lived sometime around 70-66 million years ago, and is the state dinosaur of California. 1/2

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Thomas R. Holtz, Jr. @arctomet.bsky.social · 1d

Full article: Critical reappraisal of a putative dicraeosaurid sauropod dinosaur from the Middle Jurassic of Gondwana and a revised view of diplodocoid evolutionary relationships and biogeography www.tandfonline.com/doi/full/10....

www.tandfonline.com

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Reposted by Milo Gaillard

Thomas R. Holtz, Jr. @arctomet.bsky.social · 1d

Animated Scutellosaurus!! (Also Dilophosaurus, prosauropods, and dimorphodonts, but I think I've seen animations of all those before...)

youtu.be/BYCjeNQvISM?...

"Hunted by Moonlight" | Dinosauria Series | Animated Teaser

YouTube video by Dead Sound

youtu.be

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Reposted by Milo Gaillard

Claude ✡️🦖🦕 @cascoclauda.bsky.social · 1d

happy #fossilfriday! this is diabloceratops, a ceratopsian from the late cretaceous. named in 2010, it is one of the oldest ceratopsids in the fossil record, and is mostly considered a basal member of the clade centrosaurinae
(art by andrey atuchin)

a partly reconstructed diabloceratops skull, as the holotype is incomplete

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Reposted by Milo Gaillard

Cary Woodruff @doublebeam.bsky.social · 1d

For #FossilFriday, it's a *NEW PACHYCEPHALOSAURID*(!), and a project that is very near and dear to my heart. Let's welcome #Brontotholus_harmoni!

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Reposted by Milo Gaillard

Thomas R. Holtz, Jr. @arctomet.bsky.social · 2d

first pachycephalosaurid from the Late Cretaceous Two Medicine Formation: effects of the Western Interior Seaway on North American pachycephalosaurid evolution url: academic.oup.com/zoolinnean/a...

#ThunderDome!

The first pachycephalosaurid from the Late Cretaceous Two Medicine Formation: effects of the Western Interior Seaway on North American pachycephalosaurid evolution

Abstract. During the latest Cretaceous, western North America experienced several regressive and transgressive cycles of the Western Interior Seaway (WIS).

academic.oup.com

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Reposted by Milo Gaillard

Darren Naish @tetzoo.bsky.social · 2d

I'm not a fan of polysyllabic scientific names that are hard to say, and also just plain hard to remember. So... Utetitan might be a yes, but zellaguymondeweyae is a no... This is a titanosaur pulled out of Alamosaurus by Greg Paul (giw.utahgeology.org/giw/index.ph...) #dinosaurs

View of Stratigraphic and anatomical evidence for multiple titanosaurid dinosaur taxa in the Late Cretaceous (Campanian-Maastrichtian) of southwestern North America

giw.utahgeology.org

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Reposted by Milo Gaillard

Thomas R. Holtz, Jr. @arctomet.bsky.social · 2d

Paul, G. S. (2025)
Stratigraphic and anatomical evidence for multiple Titanosaurid dinosaur taxa in the late Late Cretaceous of southwestern North America. Geology of the Intermountain West 12: 201-220.
doi.org/10.31711/giw...

Stratigraphic and anatomical evidence for multiple titanosaurid dinosaur taxa in the Late Cretaceous (Campanian-Maastrichtian) of southwestern North America | Geology of the Intermountain We...

doi.org

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Milo Gaillard @milogaillard2.bsky.social · 2d

His tyrannosaur paper also had a lot of issues with typos, grammar, and sentence structure. This is just kind of par for the course, imo.

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Milo Gaillard @milogaillard2.bsky.social · 2d

I read the paper. My thoughts on it can be seen, here. I will say that I do take back what I said about “Utetitan zellaguymondeweyae” being a terrible name. I overlooked that it’s supposed to honor the Ute people and his grandmother. Still a mouthful, lol. bsky.app/profile/milo...

Milo Gaillard @milogaillard2.bsky.social · 2d

So, this got published yesterday. 1/8
giw.utahgeology.org/giw/index.ph...

Stratigraphic and anatomical evidence for multiple titanosaurid dinosaur taxa in the Late Cretaceous (Campanian-Maastrichtian) of southwestern North America | Geology of the Intermountain We...

giw.utahgeology.org

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Milo Gaillard @milogaillard2.bsky.social · 2d

Wait. I take back what I said about “Utetitan zellaguymondeweyae” being a terrible name. It’s supposed to honor Ute people who lived in central Utah (where “Utetitan” was found) and his grandmother. So, I admit I was a bit too harsh on the name, but it’s still a mouthful, imo.

Milo Gaillard @milogaillard2.bsky.social · 2d

First off, the paper tries splitting the North Horn specimen into its own genus and species, “Utetitan zellaguymondeweyae” (horrible name, btw). He even went as far as to erect a new subfamily, “Utetitaninae.” 3/8

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Milo Gaillard @milogaillard2.bsky.social · 2d

Bottom line: this paper is terrible, imo. Some good points made & some good ideas here, but terribly executed. Although I haven’t seen the specimens myself, I’m 100% sure that “Utetitan” is just Alamosaurus, and will inevitably get sunk back into Alamosaurus. 8/8

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Milo Gaillard @milogaillard2.bsky.social · 2d

There is a case to be made for T. mcraeensis, the Ojo Alamo tyrannosaur, and the Javelina tyrannosaur being distinct from T. rex (though not necessarily on a generic level, although that is arbitrary), but literally even the biggest splitters agree that North Horn is rex. 7/8

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Milo Gaillard @milogaillard2.bsky.social · 2d

Last thing I want to say: there is literally 0 evidence that the North Horn tyrannosaur specimen is distinct from T. rex at all. As you can see in this image from Sampson and Lowen 2005 (www.tandfonline.com/doi/abs/10.1...), it’s identical to T. rex 6/8

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Milo Gaillard @milogaillard2.bsky.social · 2d

And of course, there’s Greg Paul’s usual downplaying of dinosaur sizes and refusal to give basically any soft tissue to his dinosaurs. That poor Alamosaurus (I refuse to call it “Utetitan”) on the left is going to die. 😭😭😭😭😭 5/8

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