Thomas R. Holtz, Jr.
@arctomet.bsky.social
3.7K followers 640 following 1.7K posts
Tyrannosaur Expert; Dinosaur Paleontologist; University of Maryland Geology Faculty; Director of the College Park Scholars-Science & Global Change Program; Science Author; Cat Dad; 🦖🦕
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arctomet.bsky.social
For the new folks, my handle refers to the arctometatarsalian condition of the foot of certain carnivorous dinosaurs (tyrannosaurids, ornithomimids, some troodontids, alvarezsaurids, and oviraptorosaurs). Arctometatarsi involve a compression of the central metatarsal (MT III) between II and IV.
Left foot of the tyrannosaurid Daspletosaurus, showing the arctometatarsalian condition
Reposted by Thomas R. Holtz, Jr.
rbreich.bsky.social
Adelita Grijalva won her election to Congress over two weeks ago, but Mike Johnson still hasn't sworn her in.

Why the delay?

Perhaps it's because Grijalva would cast the final vote needed to release the Epstein files.
Reposted by Thomas R. Holtz, Jr.
stevebrusatte.bsky.social
Debbie Brockman is a journalist for WGN, Chicago's most iconic television news station.

Here she is being wrestled to the ground, handcuffed & detained by masked ICE agents in broad daylight.

ICE rammed into her vehicle, dragged her out & whisked her away. Whereabouts unknown.

This is fascism.
heartlandsignal.bsky.social
BREAKING: Masked Border Patrol agents aggressively arrested WGN video producer Debbie Brockman in Lincoln Square Friday morning, supposedly for "obstructing justice." (Video via Josh Thomas on Facebook)

Follow @heartlandsignal for more.
Reposted by Thomas R. Holtz, Jr.
kimota1977.bsky.social
Dude was like “IF THE DEMOCRATS WON YOU’D HAVE A REPRESENTATIVE DEMOCRACY FOR MILLIONS MORE PEOPLE!! CAN YOU IMAGINE THE HORROR!?!?”
atrupar.com
Thune: "If the Democrats had won the majority, they probably would've tried to nuke the filibuster. And then you'd have four new senators from Puerto Rico and DC, you'd have a packed Supreme Court, you'd have abortion on demand ... "
Reposted by Thomas R. Holtz, Jr.
raskin.house.gov
And the lawsuits will follow promptly. Government shutdowns give presidents no additional authority to dismiss federal workers. We’ll fight these outrageous assaults on civil servants and public services.
Reposted by Thomas R. Holtz, Jr.
doublebeam.bsky.social
For #FossilFriday, it's a *NEW PACHYCEPHALOSAURID*(!), and a project that is very near and dear to my heart. Let's welcome #Brontotholus_harmoni!
arctomet.bsky.social
Nope, Google is wrong. "Dimorphodon" is a genus name: genera do not have plurals; their are collective singular entities. "Dimorphodonts" is a more general term for "pterosaurs near Dimorphodon on the family tree", including Dimorphodontidae as well as other critters nearby.
arctomet.bsky.social
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
Reposted by Thomas R. Holtz, Jr.
serpenillus.bsky.social
The huge Deinocheirus in its habitat. Illustration I did for the Fukui Prefectural Dinosaur Museum in Japan

In this illustration you can see a scene set in Late Cretaceous Asia where an adult Deinocheirus is scaring away a pair of young Tarbosaurus

#paleoart #dinosaur #art
Illustration depicting three Deinocheirus in a Late Cretaceous swamp. The one of the front is chasing a way a pair of juvenile Tarbosaurus in the foreground
arctomet.bsky.social
S. Nosotti et al. (2025)
A new specimen of Macroplacus raeticus Schubert-Klempnauer, 1975 (Sauropterygia, Placodontia) from the Upper Triassic of Italy, with remarks on placodont phylogeny
Rivista Italiana di Paleontologia e Stratigrafia 131(3): 687-721

riviste.unimi.it/index.php/RI...
doi.org
arctomet.bsky.social
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
arctomet.bsky.social
#FossilFriday The skull of Ankylosaurus magniventris AMNH 5214 @amnh.org
Skull of Ankylosaurus in left lateral and dorsal view
Reposted by Thomas R. Holtz, Jr.
journalsystpal.bsky.social
New paper in JSP!
Mannion & Moore reassessed a putative dicraeosaurid sauropod dinosaur from the Middle Jurassic of Gondwana and revised the evolutionary relationships and biogeography of diplodocoids 🦕 Read the full study here: buff.ly/tNyUNS9
#Paleosky @pdmannion.bsky.social #FossilFriday #NHM
arctomet.bsky.social
Daniel Eduardo Pomar, Cristian David Benavides-Cabra & José Alejandro Narváez-Rincón (2025)
The first record of a thunnosaurian ichthyosaur from the upper Albian of South America
Journal of South American Earth Sciences 168: 105824
doi: doi.org/10.1016/j.js...
www.sciencedirect.com/science/arti...
Redirecting
doi.org
arctomet.bsky.social
Yuta Tsukiji, Soki Hattori & Yoichi Azuma (2025)
First didactyl theropod track from the Lower Cretaceous Kitadani Formation, Tetori Group, Fukui, Japan
Cretaceous Research 106249
doi: doi.org/10.1016/j.cr...
www.sciencedirect.com/science/arti...
Redirecting
doi.org
arctomet.bsky.social
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