Lightnews — Scholar-powered news

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; 🦖🦕

Posts Media Videos Starter Packs

Pinned

Thomas R. Holtz, Jr. @arctomet.bsky.social · Nov 14

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

9 37 280

Reposted by Thomas R. Holtz, Jr.

Bingcai Liu @bingcailiu.bsky.social · 14h

Excited to share our research on the evolution of fossil forests from the Devonian to Jurassic! By analyzing 38 global fossil forests, we explored key parameters to better understand how these fossil forests developed over time.

doi.org/10.1016/j.ea...

1 24 74

Reposted by Thomas R. Holtz, Jr.

Zack Labe @zacklabe.com · 13h

Unfortunately still no #Arctic sea ice thickness and volume update for the month of September on my website... data issues from the U.S. government shutdown

PIOMAS notice: psc.apl.uw.edu/research/pro...

Screenshot that says "August 2025 Monthly Update [September update delayed due to US Govn’t shutdown resulting in unavailable data]"

5 31 110

Reposted by Thomas R. Holtz, Jr.

George Takei @georgetakei.bsky.social · 14h

Last I checked the GOP controls all branches of our government.

Tweet from MeidasTouch: “Wow that’s crazy. Who’s running the federal government?”
Below, Acyn’s tweet quotes Rep. Mike Johnson: “If you look at polling, people’s faith in the federal government is at an all-time low. Why? Because they don’t see that it’s being done well.”
A C-SPAN screenshot shows Johnson speaking with another man standing beside him.

350 1.9K 6.7K

Reposted by Thomas R. Holtz, Jr.

John Hawks @johnhawks.net · 15h

Paleoanthropology can be confusing with names. Why would scientists use “Denisovan” instead of coming up with a species name? Or “modern human” instead of Homo sapiens? And why didn’t some names ever catch on, like the Heidelbergers or the chumanzees?

www.johnhawks.net/p/informal-h...

Informal hominins, from Denisovan to superarchaic

In a new research article, I review the ways that paleoanthropologists name ancient groups outside the Linnaean system.

www.johnhawks.net

3 14 36

Reposted by Thomas R. Holtz, Jr.

George Takei @georgetakei.bsky.social · 15h

New plot wrinkle!

Daily Mail headline reads: “EXCLUSIVE: Pete Hegseth wages war on his wrinkles with BOTOX injections after blasting ‘fat troops’ and unveiling new fitness standards.”
Below the headline is a photo of Pete Hegseth wearing a blue jacket, speaking to another man.

99 250 1.9K

Reposted by Thomas R. Holtz, Jr.

Zack Labe @zacklabe.com · 1d

September #Arctic sea ice extent since the year 1850 - comparison now updated through 2025

I have a couple of other sea ice reconstructions on my website too: zacklabe.com/arctic-sea-i...

Line graph time series of September Arctic sea ice extent for every year from 1850 through 2025. Two datasets are compared in this time series. The Walsh et al. 2019 reconstruction is shown with a solid blue line. The NSIDC Sea Ice Index v3 is shown with a dashed red line only for the satellite era. There is large interannual variability and a long-term decreasing trend over the last few decades.

2 33 110

Reposted by Thomas R. Holtz, Jr.

Dave Levitan @davelevitan.bsky.social · 1d

“We can give $20 billion to Argentina but we can’t afford the CDC’s measles experts” is a hell of an argument

280 5.4K 18K

Reposted by Thomas R. Holtz, Jr.

Robert Reich @rbreich.bsky.social · 2d

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.

580 4.2K 15K

Reposted by Thomas R. Holtz, Jr.

Steve Brusatte @stevebrusatte.bsky.social · 2d

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.

Heartland Signal @heartlandsignal.bsky.social · 2d

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.

1 19 39

Reposted by Thomas R. Holtz, Jr.

Miracle Man @kimota1977.bsky.social · 2d

Dude was like “IF THE DEMOCRATS WON YOU’D HAVE A REPRESENTATIVE DEMOCRACY FOR MILLIONS MORE PEOPLE!! CAN YOU IMAGINE THE HORROR!?!?”

Aaron Rupar @atrupar.com · 2d

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 ... "

4 25 93

Reposted by Thomas R. Holtz, Jr.

Rep. Jamie Raskin @raskin.house.gov · 2d

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.

390 3.8K 14K

Reposted by Thomas R. Holtz, Jr.

Cary Woodruff @doublebeam.bsky.social · 2d

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

2 9 38

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

Osteological correlates of the respiratory and vascular systems in the neural canals of Mesozoic ornithurines Ichthyornis and Janavis - Atterholt - The Anatomical Record - Wiley Online Library anatomypubs.onlinelibrary.wiley.com/doi/10.1002/...

Osteological correlates of the respiratory and vascular systems in the neural canals of Mesozoic ornithurines Ichthyornis and Janavis

In birds, the neural canal houses a variety of anatomical structures including the spinal cord, meninges, spinal vasculature, and respiratory diverticula. Among these, paramedullary diverticula and t...

anatomypubs.onlinelibrary.wiley.com

1 9

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

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.

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

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

2 10

Reposted by Thomas R. Holtz, Jr.

Gabriel Ugueto @serpenillus.bsky.social · 2d

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

11 110 380

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

www.manchester.ac.uk/about/news/r...

Rare Jurassic 'Sword Dragon' prehistoric reptile discovered in the UK

A near-complete skeleton found on UK’s Jurassic Coast has been identified as a new and rare species of ichthyosaur - a type of prehistoric marine reptile that once ruled the ancient oceans.The dolphin...

www.manchester.ac.uk

2 20 120

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

A new long and narrow‐snouted ichthyosaur illuminates a complex faunal turnover during an undersampled Early Jurassic (Pliensbachian) interval - Lomax - 2025 - Papers in Palaeontology - Wiley Online Library onlinelibrary.wiley.com/doi/10.1002/...

A new long and narrow‐snouted ichthyosaur illuminates a complex faunal turnover during an undersampled Early Jurassic (Pliensbachian) interval

Ichthyosaurian faunas before and after the Pliensbachian stage of the Early Jurassic are known from numerous, often complete fossils. The two faunas are very different taxonomically, with only one of...

onlinelibrary.wiley.com

3 34

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

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

1 8

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

#Geol104playlist The Rise of the Dinosaurs
youtu.be/PP2FyYSUJ54?...

T.Rex - Children Of The Revolution - Official HD Promo Video

YouTube video by T.Rex

youtu.be

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

Breeden, B. T. et al. (2025). New specimens of Eucoelophysis baldwini from the Upper Triassic Chinle Formation, northern New Mexico, U.S.A., and their implications for the evolution of Silesauridae (Dinosauriformes). Journal of Vertebrate Paleontology. doi.org/10.1080/0272...

New specimens of Eucoelophysis baldwini from the Upper Triassic Chinle Formation, northern New Mexico, U.S.A., and their implications for the evolution of Silesauridae (Dinosauriformes)

Eucoelophysis baldwini is a silesaurid dinosauriform known only from a single fragmentary postcranial skeleton from the Petrified Forest Member of the Upper Triassic Chinle Formation near Ghost Ran...

doi.org

2 10

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

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

2 14 39

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

#FossilFriday The skull of Ankylosaurus magniventris AMNH 5214 @amnh.org

Skull of Ankylosaurus in left lateral and dorsal view

3 20 140

Reposted by Thomas R. Holtz, Jr.

🦕Journal of Systematic Palaeontology🦴 @journalsystpal.bsky.social · 2d

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

11 29

Thomas R. Holtz, Jr. @arctomet.bsky.social · 3d

New tetrapod remains help constrain the age of a peculiar assemblage, including early dinosaurs and pterosaur precursors, from the Upper Triassic of southern Brazil: Journal of Vertebrate Paleontology: Vol 0, No 0 - Get Access www.tandfonline.com/doi/full/10....

New tetrapod remains help constrain the age of a peculiar assemblage, including early dinosaurs and pterosaur precursors, from the Upper Triassic of southern Brazil

The Hyperodapedon Assemblage Zone (AZ) is a key global marker of the Carnian stage in the Late Triassic. In the Candelária Sequence of Brazil (Rio Grande do Sul), it splits into the lower Hyperodap...

www.tandfonline.com

5 33