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.
Happy #Thankgiving to those celebrating! When you are carving into your turkey, remember, its really an avian #dinosaur. So if you want to see a #HouseofTurkeys, visit @museumoftherockies.bsky.social cause we got lots o dat! #paleontology
November 27, 2025 at 5:20 PM
Happy #Thankgiving to those celebrating! When you are carving into your turkey, remember, its really an avian #dinosaur. So if you want to see a #HouseofTurkeys, visit @museumoftherockies.bsky.social cause we got lots o dat! #paleontology
Reposted by Thomas R. Holtz, Jr.
Reposted by Thomas R. Holtz, Jr.
Rumor is even GOP House members are sick of being treated like potted plants, with many more threatening early departure.
November 27, 2025 at 9:17 PM
Rumor is even GOP House members are sick of being treated like potted plants, with many more threatening early departure.
Reposted by Thomas R. Holtz, Jr.
As you're enjoying turkey with your family, think of Any Lucia Lopez Belloza.
19 years old, freshman in college, about to board a flight home to join her family for Thanksgiving.
Detained by ICE, then deported in *direct violation* of a judge's order.
abcnews.go.com/US/19-year-c...
19 years old, freshman in college, about to board a flight home to join her family for Thanksgiving.
Detained by ICE, then deported in *direct violation* of a judge's order.
abcnews.go.com/US/19-year-c...
19-year-old college student deported despite judge's order blocking her removal: Lawyer
A 19-year-old college student who was on her way to surprise her family for Thanksgiving break was detained at a Boston airport and later deported.
abcnews.go.com
November 27, 2025 at 11:03 PM
As you're enjoying turkey with your family, think of Any Lucia Lopez Belloza.
19 years old, freshman in college, about to board a flight home to join her family for Thanksgiving.
Detained by ICE, then deported in *direct violation* of a judge's order.
abcnews.go.com/US/19-year-c...
19 years old, freshman in college, about to board a flight home to join her family for Thanksgiving.
Detained by ICE, then deported in *direct violation* of a judge's order.
abcnews.go.com/US/19-year-c...
Reposted by Thomas R. Holtz, Jr.
To celebrate the 85th SVP Meeting 2025, we've assembled an open access collection of landmark JSP vertebrate palaeontology papers.
Next: 'The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida)' by Brusatte et al. buff.ly/Gs8wKDO - a primary division of the vertebrate tree of life #PaleoSky
Next: 'The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida)' by Brusatte et al. buff.ly/Gs8wKDO - a primary division of the vertebrate tree of life #PaleoSky
November 25, 2025 at 8:00 AM
To celebrate the 85th SVP Meeting 2025, we've assembled an open access collection of landmark JSP vertebrate palaeontology papers.
Next: 'The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida)' by Brusatte et al. buff.ly/Gs8wKDO - a primary division of the vertebrate tree of life #PaleoSky
Next: 'The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida)' by Brusatte et al. buff.ly/Gs8wKDO - a primary division of the vertebrate tree of life #PaleoSky
Reposted by Thomas R. Holtz, Jr.
We share the world with animals, and sometimes unusual things happen. If you know Victoria, BC, you’ll know my neighborhood near the Parliament Buildings is a pretty dense residential area, surrounded by other urban areas. But every once in a while cougars randomly show up, as in this case from 2015
Dramatic cougar chase in Victoria, B.C. ends with tranquilizer dart
Conservation officers have managed to shoot a large cougar with a tranquilizer dart -- ending a terrifying chase through the streets near the edge of the provincial legislature grounds in Victoria.
www.ctvnews.ca
November 27, 2025 at 11:12 PM
We share the world with animals, and sometimes unusual things happen. If you know Victoria, BC, you’ll know my neighborhood near the Parliament Buildings is a pretty dense residential area, surrounded by other urban areas. But every once in a while cougars randomly show up, as in this case from 2015
Reposted by Thomas R. Holtz, Jr.
Reposted by Thomas R. Holtz, Jr.
What's behind anti-immigrant rhetoric in the UK:
'About one in five Britons refused to acknowledge that migration had fallen, even when presented with the official data'
'People choose to disregard statistics that do not correlate with their beliefs'
www.nytimes.com/2025/11/27/w...
'About one in five Britons refused to acknowledge that migration had fallen, even when presented with the official data'
'People choose to disregard statistics that do not correlate with their beliefs'
www.nytimes.com/2025/11/27/w...
The British Public Thinks Immigration Is Up. It’s Actually Down, Sharply.
www.nytimes.com
November 27, 2025 at 3:14 PM
What's behind anti-immigrant rhetoric in the UK:
'About one in five Britons refused to acknowledge that migration had fallen, even when presented with the official data'
'People choose to disregard statistics that do not correlate with their beliefs'
www.nytimes.com/2025/11/27/w...
'About one in five Britons refused to acknowledge that migration had fallen, even when presented with the official data'
'People choose to disregard statistics that do not correlate with their beliefs'
www.nytimes.com/2025/11/27/w...
Luis F. Camacho and Miguel B. Araujo (2025)
Global evidence of non-pyramidal and uniform ratios of animal diversity across terrestrial trophic levels
Proceedings of the Royal Society B: Biological Sciences 292(2059): 20252335
doi: doi.org/10.1098/rspb...
royalsocietypublishing.org/doi/10.1098/...
Global evidence of non-pyramidal and uniform ratios of animal diversity across terrestrial trophic levels
Proceedings of the Royal Society B: Biological Sciences 292(2059): 20252335
doi: doi.org/10.1098/rspb...
royalsocietypublishing.org/doi/10.1098/...
Global evidence of non-pyramidal and uniform ratios of animal diversity across terrestrial trophic levels | Proceedings of the Royal Society B: Biological Sciences
Thermodynamics imposes a well-established pyramidal distribution of energy availability
across trophic levels, but whether species richness follows the same pattern remains
unclear. In this study, we ...
doi.org
November 27, 2025 at 12:09 PM
Luis F. Camacho and Miguel B. Araujo (2025)
Global evidence of non-pyramidal and uniform ratios of animal diversity across terrestrial trophic levels
Proceedings of the Royal Society B: Biological Sciences 292(2059): 20252335
doi: doi.org/10.1098/rspb...
royalsocietypublishing.org/doi/10.1098/...
Global evidence of non-pyramidal and uniform ratios of animal diversity across terrestrial trophic levels
Proceedings of the Royal Society B: Biological Sciences 292(2059): 20252335
doi: doi.org/10.1098/rspb...
royalsocietypublishing.org/doi/10.1098/...
‘Anti-woke’ policies blamed for falling attendance at some US conferences www.nature.com/articles/d41...
‘Anti-woke’ policies blamed for falling attendance at some US conferences
Scientific meetings that support Black, Latino and Indigenous researchers are grappling with funding cuts and other restrictions.
www.nature.com
November 27, 2025 at 12:06 PM
‘Anti-woke’ policies blamed for falling attendance at some US conferences www.nature.com/articles/d41...
Observations on #PrehistoricPlanetIceAge: wonderful, of course. But a strange reluctance in narration to a) state where in the world a scene takes place and b) use genus names. Odd, since no such reluctance in the Mesozoic series.
November 27, 2025 at 12:29 AM
Observations on #PrehistoricPlanetIceAge: wonderful, of course. But a strange reluctance in narration to a) state where in the world a scene takes place and b) use genus names. Odd, since no such reluctance in the Mesozoic series.
Mystery owner of African hominin foot identified www.nature.com/articles/d41...
Mystery owner of African hominin foot identified
Fossils newly discovered in Ethiopia indicate that previously unidentified foot bones belong to the ancient human relative Australopithecus deyiremeda.
www.nature.com
November 26, 2025 at 8:56 PM
Mystery owner of African hominin foot identified www.nature.com/articles/d41...
Reposted by Thomas R. Holtz, Jr.
Foot and Mouth: owner of mysterious Burtele foot linked with dental remains and identified as Australopithecus deyiremeda. Just out in @nature.com www.nature.com/articles/s41...
New finds shed light on diet and locomotion in Australopithecus deyiremeda - Nature
3.4-million-year-old hominin fossils discovered in Ethiopia provide insight into the diet and locomotion of Australopithecus deyiremeda.
www.nature.com
November 26, 2025 at 6:26 PM
Foot and Mouth: owner of mysterious Burtele foot linked with dental remains and identified as Australopithecus deyiremeda. Just out in @nature.com www.nature.com/articles/s41...
Reposted by Thomas R. Holtz, Jr.
Read the accompanying News and Views from Fred Spoor www.nature.com/articles/d41...
Mystery owner of African hominin foot identified
Fossils newly discovered in Ethiopia indicate that previously unidentified foot bones belong to the ancient human relative Australopithecus deyiremeda.
www.nature.com
November 26, 2025 at 6:26 PM
Read the accompanying News and Views from Fred Spoor www.nature.com/articles/d41...
Reposted by Thomas R. Holtz, Jr.
I love this so much!
I just think it would be neat if turkeys used the same technique to draw us
November 26, 2025 at 8:40 PM
I love this so much!
Reposted by Thomas R. Holtz, Jr.
UC Berkeley is still trying to get me to donate $ as the parent of an alum. Um, no. Not for this.
UC Berkeley (1) fires losing football coach, (2) will continue to pay him $10.9 million, (3) hires prominent anti-vax wacko as interim coach. Great work, California! #highereducationpriorities @governor.ca.gov
Cal makes an extremely unlikely, controversial choice for fill-in coach
Nick Rolovich is set to lead the Bears for at least one game this season.
www.sfgate.com
November 26, 2025 at 8:40 PM
UC Berkeley is still trying to get me to donate $ as the parent of an alum. Um, no. Not for this.
Neuroanatomical convergence between pterosaurs and non-avian paravians in the evolution of flight: Current Biology www.cell.com/current-biol...
Neuroanatomical convergence between pterosaurs and non-avian paravians in the evolution of flight
Bronzati et al. show that pterosaurs, the first flying reptiles, evolved brains resembling
bird precursors but not modern birds. They also demonstrate that, unlike birds, which
built on inherited dino...
www.cell.com
November 26, 2025 at 4:33 PM
Neuroanatomical convergence between pterosaurs and non-avian paravians in the evolution of flight: Current Biology www.cell.com/current-biol...
Reposted by Thomas R. Holtz, Jr.
I told my students the same, and that they should use @arctomet.bsky.social's helpfully labeled diagram to steer the Thanksgiving-dinner conversation back to something that really matters, such as theropod evolutionary lineages. 🧪🦃🦖
November 26, 2025 at 1:53 PM
I told my students the same, and that they should use @arctomet.bsky.social's helpfully labeled diagram to steer the Thanksgiving-dinner conversation back to something that really matters, such as theropod evolutionary lineages. 🧪🦃🦖
Reposted by Thomas R. Holtz, Jr.
Very polarizing views and interesting look into priorities 🧐
Trump voting men rank having children as their highest priority in life, and rank having emotional stability dead last. Those poor children.
November 26, 2025 at 1:29 PM
Very polarizing views and interesting look into priorities 🧐
Reposted by Thomas R. Holtz, Jr.
Years of work involving an amazing team at BBCSstudios Framestore AppleTV, our series #PrehistoricPlanetIceAge is out now on #AppleTV. Huge thanks to everyone involved. All 5 eps have been released!
November 26, 2025 at 10:07 AM
Years of work involving an amazing team at BBCSstudios Framestore AppleTV, our series #PrehistoricPlanetIceAge is out now on #AppleTV. Huge thanks to everyone involved. All 5 eps have been released!
PeerJ<br><br>Mandibular form and function is more disparate in amniotes than in non-amniote tetrapods from the late Palaeozoic<br><br>https://peerj.com/articles/20243/<br><br>@peerj.bsky.social
November 26, 2025 at 1:00 PM
PeerJ<br><br>Mandibular form and function is more disparate in amniotes than in non-amniote tetrapods from the late Palaeozoic<br><br>https://peerj.com/articles/20243/<br><br>@peerj.bsky.social
H. Rivera-Sylva et al. (2025)
Pterosaurs (Pterosauria) from the Cerro del Pueblo Formation (Late Campanian) of Coahuila, Mexico
Palaeovertebrata 48(2)-e1.
doi: 10.18563/pv.48.2.e1
www.palaeovertebrata.com/Articles/vie...
Pterosaurs (Pterosauria) from the Cerro del Pueblo Formation (Late Campanian) of Coahuila, Mexico
Palaeovertebrata 48(2)-e1.
doi: 10.18563/pv.48.2.e1
www.palaeovertebrata.com/Articles/vie...
www.palaeovertebrata.com
November 26, 2025 at 12:58 PM
H. Rivera-Sylva et al. (2025)
Pterosaurs (Pterosauria) from the Cerro del Pueblo Formation (Late Campanian) of Coahuila, Mexico
Palaeovertebrata 48(2)-e1.
doi: 10.18563/pv.48.2.e1
www.palaeovertebrata.com/Articles/vie...
Pterosaurs (Pterosauria) from the Cerro del Pueblo Formation (Late Campanian) of Coahuila, Mexico
Palaeovertebrata 48(2)-e1.
doi: 10.18563/pv.48.2.e1
www.palaeovertebrata.com/Articles/vie...
Rebecca L. Schmeisser McKean (2025)
A new species of Pahasapasaurus (Plesiosauria: Polycotylidae) from the Upper Cretaceous Tropic Shale (lower Turonian) of southern Utah, U.S.A.
Cretaceous Research 106269
doi: doi.org/10.1016/j.cr...
www.sciencedirect.com/science/arti...
A new species of Pahasapasaurus (Plesiosauria: Polycotylidae) from the Upper Cretaceous Tropic Shale (lower Turonian) of southern Utah, U.S.A.
Cretaceous Research 106269
doi: doi.org/10.1016/j.cr...
www.sciencedirect.com/science/arti...
Redirecting
doi.org
November 26, 2025 at 12:57 PM
Rebecca L. Schmeisser McKean (2025)
A new species of Pahasapasaurus (Plesiosauria: Polycotylidae) from the Upper Cretaceous Tropic Shale (lower Turonian) of southern Utah, U.S.A.
Cretaceous Research 106269
doi: doi.org/10.1016/j.cr...
www.sciencedirect.com/science/arti...
A new species of Pahasapasaurus (Plesiosauria: Polycotylidae) from the Upper Cretaceous Tropic Shale (lower Turonian) of southern Utah, U.S.A.
Cretaceous Research 106269
doi: doi.org/10.1016/j.cr...
www.sciencedirect.com/science/arti...
M. Reolid & J. Cardenal (2025)
Description and interpretation of theropod tracks from the Berriasian tidal flats of the South-Iberian Palaeomargin (Internal Prebetic, S Spain)
Annales Societatis Geologorum Poloniae 95(3): 179-188
DOI: doi.org/10.14241/asg...
geojournals.pgi.gov.pl/asgp/article...
Description and interpretation of theropod tracks from the Berriasian tidal flats of the South-Iberian Palaeomargin (Internal Prebetic, S Spain)
Annales Societatis Geologorum Poloniae 95(3): 179-188
DOI: doi.org/10.14241/asg...
geojournals.pgi.gov.pl/asgp/article...
doi.org
November 26, 2025 at 12:56 PM
M. Reolid & J. Cardenal (2025)
Description and interpretation of theropod tracks from the Berriasian tidal flats of the South-Iberian Palaeomargin (Internal Prebetic, S Spain)
Annales Societatis Geologorum Poloniae 95(3): 179-188
DOI: doi.org/10.14241/asg...
geojournals.pgi.gov.pl/asgp/article...
Description and interpretation of theropod tracks from the Berriasian tidal flats of the South-Iberian Palaeomargin (Internal Prebetic, S Spain)
Annales Societatis Geologorum Poloniae 95(3): 179-188
DOI: doi.org/10.14241/asg...
geojournals.pgi.gov.pl/asgp/article...
A.O. Averianov, A.V. Sizov, D.V. Grigoriev, V.V. Kolchanov &
P.P. Skutschas (2025)
A sauropod Tengrisaurus starkovi from the Lower Cretaceous of Transbaikalia, Russia, and Asiatic origin of Titanosauria
Cretaceous Research 106271
doi: doi.org/10.1016/j.cr...
www.sciencedirect.com/science/arti...
P.P. Skutschas (2025)
A sauropod Tengrisaurus starkovi from the Lower Cretaceous of Transbaikalia, Russia, and Asiatic origin of Titanosauria
Cretaceous Research 106271
doi: doi.org/10.1016/j.cr...
www.sciencedirect.com/science/arti...
Redirecting
doi.org
November 26, 2025 at 12:51 PM
A.O. Averianov, A.V. Sizov, D.V. Grigoriev, V.V. Kolchanov &
P.P. Skutschas (2025)
A sauropod Tengrisaurus starkovi from the Lower Cretaceous of Transbaikalia, Russia, and Asiatic origin of Titanosauria
Cretaceous Research 106271
doi: doi.org/10.1016/j.cr...
www.sciencedirect.com/science/arti...
P.P. Skutschas (2025)
A sauropod Tengrisaurus starkovi from the Lower Cretaceous of Transbaikalia, Russia, and Asiatic origin of Titanosauria
Cretaceous Research 106271
doi: doi.org/10.1016/j.cr...
www.sciencedirect.com/science/arti...