Thomas R. Holtz, Jr.
@arctomet.bsky.social
Tyrannosaur Expert; Dinosaur Paleontologist; University of Maryland Geology Faculty; Director of the College Park Scholars-Science & Global Change Program; Science Author; Cat Dad; 🦖🦕
Pinned
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.
Reposted by Thomas R. Holtz, Jr.
Kudos to @discovermag.bsky.social for quickly posting an editor's note on their article about a paper that was just retracted. There were a lot of stories about this article last summer as a consequence of the Comet Research Group's aggressive self promotion. www.discovermagazine.com/a-comet-coul...
A Comet Could’ve Caused Rapid Climate Shift Around 12,800 Years Ago
Learn more about the Younger Dryas event, an ancient climate change catastrophe that’s typically attributed to glacial meltwater.
www.discovermagazine.com
February 18, 2026 at 5:59 PM
Kudos to @discovermag.bsky.social for quickly posting an editor's note on their article about a paper that was just retracted. There were a lot of stories about this article last summer as a consequence of the Comet Research Group's aggressive self promotion. www.discovermagazine.com/a-comet-coul...
Reposted by Thomas R. Holtz, Jr.
The most unfortunately timed paper in the history of scientific publishing.
February 17, 2026 at 10:43 PM
The most unfortunately timed paper in the history of scientific publishing.
Reposted by Thomas R. Holtz, Jr.
"Is there technology the left is excited about?" is the kind of question you only ask if you're wildly naive about technology.
mRNA vaccines. Heat pumps. Offshore wind. Urban mining. Sodium batteries.
But god forbid we're not fawning over every new implementation of Making Computers Bad At Math.
mRNA vaccines. Heat pumps. Offshore wind. Urban mining. Sodium batteries.
But god forbid we're not fawning over every new implementation of Making Computers Bad At Math.
February 18, 2026 at 2:58 PM
"Is there technology the left is excited about?" is the kind of question you only ask if you're wildly naive about technology.
mRNA vaccines. Heat pumps. Offshore wind. Urban mining. Sodium batteries.
But god forbid we're not fawning over every new implementation of Making Computers Bad At Math.
mRNA vaccines. Heat pumps. Offshore wind. Urban mining. Sodium batteries.
But god forbid we're not fawning over every new implementation of Making Computers Bad At Math.
Reposted by Thomas R. Holtz, Jr.
@chrisnsimms.bsky.social @flintdibble.bsky.social Yet another Younger Dryas Comet Impact Hypothesis paper bites the dust.
This time because they couldn't tell the difference between marine foraminifera and cosmic impact indicators 🙃
This time because they couldn't tell the difference between marine foraminifera and cosmic impact indicators 🙃
“The authors claim these are spherule fragments identified as cosmic impact indicators. During expert consultation, these have been identified as marine foraminifera.”
💀
💀
Retraction: A 12,800-year-old layer with cometary dust, microspherules, and platinum anomaly recorded in multiple cores from Baffin Bay
journals.plos.org
February 18, 2026 at 7:08 AM
@chrisnsimms.bsky.social @flintdibble.bsky.social Yet another Younger Dryas Comet Impact Hypothesis paper bites the dust.
This time because they couldn't tell the difference between marine foraminifera and cosmic impact indicators 🙃
This time because they couldn't tell the difference between marine foraminifera and cosmic impact indicators 🙃
Reposted by Thomas R. Holtz, Jr.
Donald Trump won in 2016 and 2024 because anti-system voters flocked to him.
Democrats need a strategy for competing with anti-system voters in 2028.
This is, in some ways, a very strong case for nominating someone like AOC over Newsom.
www.gelliottmorris.com/p/meet-ameri...
Democrats need a strategy for competing with anti-system voters in 2028.
This is, in some ways, a very strong case for nominating someone like AOC over Newsom.
www.gelliottmorris.com/p/meet-ameri...
Meet America’s new swing voter: The anti-system voter. (Or: Why Democrats should think through nominating AOC in 2028)
A new paper finds anti-system sentiment — not left-right ideology — decided the 2016 and 2024 elections
www.gelliottmorris.com
February 18, 2026 at 11:02 AM
Donald Trump won in 2016 and 2024 because anti-system voters flocked to him.
Democrats need a strategy for competing with anti-system voters in 2028.
This is, in some ways, a very strong case for nominating someone like AOC over Newsom.
www.gelliottmorris.com/p/meet-ameri...
Democrats need a strategy for competing with anti-system voters in 2028.
This is, in some ways, a very strong case for nominating someone like AOC over Newsom.
www.gelliottmorris.com/p/meet-ameri...
Reposted by Thomas R. Holtz, Jr.
This remains true even though I live with my tiny cat housemate. Rarely a day goes by without me pointing at Sylvie and exclaiming "It's a small cat!" in a pleasantly surprised voice.
February 18, 2026 at 8:06 AM
This remains true even though I live with my tiny cat housemate. Rarely a day goes by without me pointing at Sylvie and exclaiming "It's a small cat!" in a pleasantly surprised voice.
Reposted by Thomas R. Holtz, Jr.
(1/5)
I am very excited to share my simultaneous triple staining method for monocot roots. This method is not only faster but also utilizes a smaller volume of stain than traditional methods and minimizes mechanical tissue damage.
www.biorxiv.org/content/10.6...
I am very excited to share my simultaneous triple staining method for monocot roots. This method is not only faster but also utilizes a smaller volume of stain than traditional methods and minimizes mechanical tissue damage.
www.biorxiv.org/content/10.6...
February 18, 2026 at 12:30 AM
(1/5)
I am very excited to share my simultaneous triple staining method for monocot roots. This method is not only faster but also utilizes a smaller volume of stain than traditional methods and minimizes mechanical tissue damage.
www.biorxiv.org/content/10.6...
I am very excited to share my simultaneous triple staining method for monocot roots. This method is not only faster but also utilizes a smaller volume of stain than traditional methods and minimizes mechanical tissue damage.
www.biorxiv.org/content/10.6...
Reposted by Thomas R. Holtz, Jr.
Here it is, your moment of zen.
February 17, 2026 at 1:43 AM
Here it is, your moment of zen.
Reposted by Thomas R. Holtz, Jr.
Reposted by Thomas R. Holtz, Jr.
I've decided to revise and update one of my most important and popular blogposts "How do I become a paleontologist?".
I still get asked this every few weeks so having a new version of this post to share is so useful to put people on track.
archosaurmusings.wordpress.com/2026/02/17/h...
I still get asked this every few weeks so having a new version of this post to share is so useful to put people on track.
archosaurmusings.wordpress.com/2026/02/17/h...
How do I become a paleontologist?
This is a revised and updated version of an old post of mine that’s now nearly 10 years old, so it seemed sensible to give it a polish and re-release it into the wild. So, what do you do to become …
archosaurmusings.wordpress.com
February 17, 2026 at 1:05 PM
I've decided to revise and update one of my most important and popular blogposts "How do I become a paleontologist?".
I still get asked this every few weeks so having a new version of this post to share is so useful to put people on track.
archosaurmusings.wordpress.com/2026/02/17/h...
I still get asked this every few weeks so having a new version of this post to share is so useful to put people on track.
archosaurmusings.wordpress.com/2026/02/17/h...
PeerJ<br><br>Behavioral implications of an embedded tyrannosaurid tooth and associated tooth marks on an articulated skull of Edmontosaurus from the Hell Creek Formation, Montana<br><br>https://peerj.com/articles/20796/<br><br>@peerj.bsky.social
February 17, 2026 at 4:47 PM
PeerJ<br><br>Behavioral implications of an embedded tyrannosaurid tooth and associated tooth marks on an articulated skull of Edmontosaurus from the Hell Creek Formation, Montana<br><br>https://peerj.com/articles/20796/<br><br>@peerj.bsky.social
Stumpf, S., Türtscher, J., López-Romero, F.A. et al. Reappraisal of the extinct barbelthroat shark †Bavariscyllium and the nebulous origin of carcharhiniform galeomorphs. Commun Biol 9, 158 (2026). doi.org/10.1038/s420...
Reappraisal of the extinct barbelthroat shark †Bavariscyllium and the nebulous origin of carcharhiniform galeomorphs - Communications Biology
Reassessment of the Jurassic shark †Bavariscyllium challenges understanding of early galeomorph evolution, showing these sharks explored diverse body forms, predating the divergence of most major body...
doi.org
February 17, 2026 at 1:17 PM
Stumpf, S., Türtscher, J., López-Romero, F.A. et al. Reappraisal of the extinct barbelthroat shark †Bavariscyllium and the nebulous origin of carcharhiniform galeomorphs. Commun Biol 9, 158 (2026). doi.org/10.1038/s420...
Reposted by Thomas R. Holtz, Jr.
"Constitutional conservative" is and always has been a dog whistle for "Nazi."
Where are those "strict Constitutionalists" now? I'm calling bs!
February 17, 2026 at 1:13 PM
"Constitutional conservative" is and always has been a dog whistle for "Nazi."
David Bowie - Changes (Official Lyric Video)
YouTube video by David Bowie
youtu.be
February 17, 2026 at 1:13 PM
Reposted by Thomas R. Holtz, Jr.
"Billionaires really like thinkers who see their exploitation of the weak as a good & natural thing."
Evolutionary biologists have a responsibility to oppose the unscientific, deeply unethical, & immoral promulgations of billionaire-funded, pseudoscientific eugenics pablum glorifying exploitation
Evolutionary biologists have a responsibility to oppose the unscientific, deeply unethical, & immoral promulgations of billionaire-funded, pseudoscientific eugenics pablum glorifying exploitation
February 15, 2026 at 3:52 PM
"Billionaires really like thinkers who see their exploitation of the weak as a good & natural thing."
Evolutionary biologists have a responsibility to oppose the unscientific, deeply unethical, & immoral promulgations of billionaire-funded, pseudoscientific eugenics pablum glorifying exploitation
Evolutionary biologists have a responsibility to oppose the unscientific, deeply unethical, & immoral promulgations of billionaire-funded, pseudoscientific eugenics pablum glorifying exploitation
Reposted by Thomas R. Holtz, Jr.
My dad has gotten back into stamp collecting and gave me some cool vintage dinosaurs. These were issued by Fujairah (part of UAE) in the 60s and Somalia in 1999.
February 14, 2026 at 2:54 PM
My dad has gotten back into stamp collecting and gave me some cool vintage dinosaurs. These were issued by Fujairah (part of UAE) in the 60s and Somalia in 1999.
Reposted by Thomas R. Holtz, Jr.
100 years of January sea surface temperature anomalies. Note the long-term warming and patterns of climate variability (e.g., El Niño/La Niña).
Data from NOAA ERSSTv5 at psl.noaa.gov/data/gridded...
Data from NOAA ERSSTv5 at psl.noaa.gov/data/gridded...
February 16, 2026 at 1:45 PM
100 years of January sea surface temperature anomalies. Note the long-term warming and patterns of climate variability (e.g., El Niño/La Niña).
Data from NOAA ERSSTv5 at psl.noaa.gov/data/gridded...
Data from NOAA ERSSTv5 at psl.noaa.gov/data/gridded...
Reposted by Thomas R. Holtz, Jr.
Ancient Mars was warm and wet, not cold and icy theconversation.com/early-mars-w...
Early Mars was warm and wet not icy, suggests latest research
The results come from the Perseverance rover’s investigation of an ancient crater lake.
theconversation.com
February 16, 2026 at 1:41 PM
Ancient Mars was warm and wet, not cold and icy theconversation.com/early-mars-w...
Reposted by Thomas R. Holtz, Jr.
As we build out Trump's lies, let's not forget that the one they were most desperate to cover up before these came out was Melania's ties to Epstein, she of the Einstein visa.
The President of the United States most likely raped girls along with his best friend Epstein.
www.dailykos.com/stories/2026...
www.dailykos.com/stories/2026...
New videos resurface showing Trump partying with underage girls
We’ve all seen Pam Bondi’s petulant performance before the House this week, screaming at members of Congress as they ask why various Epstein files remain redacted for Co-conspirators and perpetrators ...
www.dailykos.com
February 16, 2026 at 5:36 AM
As we build out Trump's lies, let's not forget that the one they were most desperate to cover up before these came out was Melania's ties to Epstein, she of the Einstein visa.
Reposted by Thomas R. Holtz, Jr.
Yup
Someone has sure already made this observation but the fact they can convert all those empty warehouses into prison camps means they could have converted them into housing, community centers, job training centers or, hell, libraries or schools all along. It’s always a matter of will not resources.
February 15, 2026 at 10:42 PM
Yup
Reposted by Thomas R. Holtz, Jr.
OpenAI ”acknowledged in its own research that LLMs will always produce hallucinations due to fundamental mathematical constraints that cannot be solved through better engineering, marking a significant admission from one of the AI industry’s leading companies.”
You can’t trust chatbots.
You can’t trust chatbots.
OpenAI admits AI hallucinations are mathematically inevitable, not just engineering flaws
In a landmark study, OpenAI researchers reveal that large language models will always produce plausible but false outputs, even with perfect data, due to fundamental statistical and computational limi...
www.computerworld.com
February 15, 2026 at 8:25 PM
OpenAI ”acknowledged in its own research that LLMs will always produce hallucinations due to fundamental mathematical constraints that cannot be solved through better engineering, marking a significant admission from one of the AI industry’s leading companies.”
You can’t trust chatbots.
You can’t trust chatbots.
Dowding, E.M., Dunne, E.M., Collins, K.S. et al. The billion-dollar case for sustaining palaeontology’s digital databases. Nat Ecol Evol (2026). doi.org/10.1038/s415...
The billion-dollar case for sustaining palaeontology’s digital databases - Nature Ecology & Evolution
The authors survey community palaeontological databases, documenting their contributions to science as well as their vulnerabilities, and provide recommendations for the future of open science databas...
doi.org
February 15, 2026 at 8:28 PM
Dowding, E.M., Dunne, E.M., Collins, K.S. et al. The billion-dollar case for sustaining palaeontology’s digital databases. Nat Ecol Evol (2026). doi.org/10.1038/s415...
Manuelli, L., Clément, G., Herbin, M. et al. A dual respiratory and auditory function for the coelacanth lung. Commun Biol (2026). doi.org/10.1038/s420...
A dual respiratory and auditory function for the coelacanth lung - Communications Biology
Synchrotron imaging of fossil and extant coelacanths reveals that the lung of extinct species likely served both respiratory and auditory functions, transmitting sound pressure to the inner ear via a ...
doi.org
February 15, 2026 at 8:27 PM
Manuelli, L., Clément, G., Herbin, M. et al. A dual respiratory and auditory function for the coelacanth lung. Commun Biol (2026). doi.org/10.1038/s420...