Michael Deak
@slothfultyrant.bsky.social
Adjunct professor at Youngstown State University who specializes in theropod and sloth thermoregulation and integument. He/Him, all opinions are my own.
Pinned
Michael Deak
@slothfultyrant.bsky.social
· Jan 14
Metabolic skinflint or spendthrift? Insights into ground sloth integument and thermophysiology revealed by biophysical modeling and clumped isotope paleothermometry - Journal of Mammalian Evolution
Remains of megatheres have been known since the 18th -century and were among the first megafaunal vertebrates to be studied. While several examples of preserved integument show a thick coverage of fur...
link.springer.com
Words cannot describe how excited I am to announce the publication of my first peer-reviewed paper published in the Journal of Mammalian Evolution! Here's a big, fancy thread summarizing everything: link.springer.com/article/10.1...
Yet another strike against the "large dinosaurs can't have any fibrous integument" narrative.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Cellular-level preservation of cutaneous spikes in an Early Cretaceous iguanodontian dinosaur - Nature Ecology & Evolution
A juvenile iguanodontian from the Lower Cretaceous of China preserves both spikes and scales in its skin that are different from integumentary structures in either non-avian dinosaurs or extant squama...
www.nature.com
February 6, 2026 at 10:40 AM
Yet another strike against the "large dinosaurs can't have any fibrous integument" narrative.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Reposted by Michael Deak
A mammoth drawings from Arcy-sur-Cure cave,France.
Outlined in red-ochre, this rotund, tuskless mammoth looks like a juvenile.
At 28,000 years old, a product of the Gravettian culture, one of the oldest examples of cave art in Europe.
The saddest mammoth from the Ice Age. 🦣😢🏺
#MammothMonday
Outlined in red-ochre, this rotund, tuskless mammoth looks like a juvenile.
At 28,000 years old, a product of the Gravettian culture, one of the oldest examples of cave art in Europe.
The saddest mammoth from the Ice Age. 🦣😢🏺
#MammothMonday
February 2, 2026 at 10:29 AM
A mammoth drawings from Arcy-sur-Cure cave,France.
Outlined in red-ochre, this rotund, tuskless mammoth looks like a juvenile.
At 28,000 years old, a product of the Gravettian culture, one of the oldest examples of cave art in Europe.
The saddest mammoth from the Ice Age. 🦣😢🏺
#MammothMonday
Outlined in red-ochre, this rotund, tuskless mammoth looks like a juvenile.
At 28,000 years old, a product of the Gravettian culture, one of the oldest examples of cave art in Europe.
The saddest mammoth from the Ice Age. 🦣😢🏺
#MammothMonday
Reposted by Michael Deak
Horner is famous in where I dig in Montana for telling a little girl that brought him a fossil to identify something to the effect of : I’d rather this thing turn to dust in the badlands than have you get it
February 1, 2026 at 3:13 AM
Horner is famous in where I dig in Montana for telling a little girl that brought him a fossil to identify something to the effect of : I’d rather this thing turn to dust in the badlands than have you get it
Reposted by Michael Deak
The woolly mammoth, a mother and her child, venture past glaciers impossibly vast for today's world.
February 1, 2026 at 7:12 PM
The woolly mammoth, a mother and her child, venture past glaciers impossibly vast for today's world.
Reposted by Michael Deak
February 1, 2026 at 9:33 AM
Completely unsurprising as many have already said. Begging MOR to distance themselves from Horner's legacy akin to what AMNH has done with Henry Osborn.
Jack Horner being in the Epstein files is not something I had on my bingo card for 2026.... Horner seemingly visited Epstein's ranch multiple times, including apparently with a student.
![Email from John Horner to Jeffrey Epstein 6/29/2012
Hi [redacted] Since i don't really know how long it would take to get from Albuquerque to the ranch and visa versa [sic], and don't know how I'm to get there (would someone be picking me up or should I rent a car) it would probably be best if you just booked the flight for me. Delta Airlines connecting through Salt Lake is the most convenient for me. My official name and frequent number [sic] is:
John Robert Horner
Delta # [REDACTED]
The geology maps are perfect.
Jack](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:eqyx54eikl5vllctjxufeavr/bafkreibg4c5lemsmrg5i5lwlbncm442psefpawe3chmcd2wgrw3qbtealy@jpeg)
![email from Lesley Groff to Jeffrey Epstein
"Reminder: John Horner and student to visit ranch today... [redacted] =ill [sic] be taking care of them...](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:eqyx54eikl5vllctjxufeavr/bafkreidykpmdkytzqsinvhufnpoyvhxkajaj6oltk2jjjoafnracumq63m@jpeg)
February 1, 2026 at 10:41 PM
Completely unsurprising as many have already said. Begging MOR to distance themselves from Horner's legacy akin to what AMNH has done with Henry Osborn.
*In epic movie guy voice*: "From the authors of the two greatest tyrannosaur books of the past decade comes...."
January 30, 2026 at 8:32 PM
*In epic movie guy voice*: "From the authors of the two greatest tyrannosaur books of the past decade comes...."
A very good review of a very good book. Plus, a lot of good information said on tyrannosaurid integument and nuances on how it would impact their thermoregulation.
My review of Mark Witton's outstandingly good book King Tyrant, published 2025, is now online at Historical Biology ... www.tandfonline.com/eprint/UIQGI... Hit me up if you want a pdf #dinosaurs #books
January 21, 2026 at 4:35 PM
A very good review of a very good book. Plus, a lot of good information said on tyrannosaurid integument and nuances on how it would impact their thermoregulation.
Reposted by Michael Deak
This is not a model. This is a "fossilised" taxidermy of a Woolly Rhino, discovered in Starunia mine in Carpathian Poland (now Ukraine) in 1929. Dating to the Pleistocene, its exquisite preservation is owed to a mixture of brine, oil and clays. 🧵
January 8, 2026 at 5:52 AM
This is not a model. This is a "fossilised" taxidermy of a Woolly Rhino, discovered in Starunia mine in Carpathian Poland (now Ukraine) in 1929. Dating to the Pleistocene, its exquisite preservation is owed to a mixture of brine, oil and clays. 🧵
Hot take: NIT (Nanotyrannus is Tyrannosaurus) is going to be the new BAND (birds are not dinosaurs).
January 6, 2026 at 10:12 PM
Hot take: NIT (Nanotyrannus is Tyrannosaurus) is going to be the new BAND (birds are not dinosaurs).
Reposted by Michael Deak
Reposted by Michael Deak
Some people really do be like:
"nah, our modern day image of dinosaurs is boring and stupid"...
"nah, our modern day image of dinosaurs is boring and stupid"...
December 29, 2025 at 6:33 AM
Some people really do be like:
"nah, our modern day image of dinosaurs is boring and stupid"...
"nah, our modern day image of dinosaurs is boring and stupid"...
The last bombshell paleontology discovery of a year of bombshell discoveries: Ammonites survived the K-PG extinction! www.nature.com/articles/s41...
Ammonite survival across the Cretaceous–Paleogene boundary confirmed by new data from Denmark - Scientific Reports
We provide a reassessment of the hypothesis of ammonite survival across the Cretaceous–Paleogene (Maastrichtian–Danian) boundary, based on new data from the lower Danian Cerithium Limestone Member at ...
www.nature.com
January 1, 2026 at 2:16 PM
The last bombshell paleontology discovery of a year of bombshell discoveries: Ammonites survived the K-PG extinction! www.nature.com/articles/s41...
2025 was a year packed with a multitude of discoveries, and I am grateful my first paper was among them. First order of business of 2026: Continue working on the sequel.....
January 1, 2026 at 2:12 PM
2025 was a year packed with a multitude of discoveries, and I am grateful my first paper was among them. First order of business of 2026: Continue working on the sequel.....
Reposted by Michael Deak
shout-out to @literallymiguel.bsky.social for having his art featured in a new publication! the study by wilson and zonneveld describes feeding traces on the holotype of the bolivian glyptodont trachycalyptoides
www.tandfonline.com/doi/full/10....
www.tandfonline.com/doi/full/10....
December 29, 2025 at 1:43 PM
shout-out to @literallymiguel.bsky.social for having his art featured in a new publication! the study by wilson and zonneveld describes feeding traces on the holotype of the bolivian glyptodont trachycalyptoides
www.tandfonline.com/doi/full/10....
www.tandfonline.com/doi/full/10....
Reposted by Michael Deak
People always draw Nanotyrannus attacking Juvenile Tyrannosaurus, so I am doing something different
December 25, 2025 at 3:48 AM
People always draw Nanotyrannus attacking Juvenile Tyrannosaurus, so I am doing something different
Reposted by Michael Deak
A very Merr Chrismas to all you hoomans out there, from Prehistoric Planet: Ice Age's Megalonyx family!
Wishing you a safe and happy holiday!
#PrehistoricPlanet #PrehistoricPlanetIceAge #paleoart #groundsloth #Christmas #meme
Wishing you a safe and happy holiday!
#PrehistoricPlanet #PrehistoricPlanetIceAge #paleoart #groundsloth #Christmas #meme
December 24, 2025 at 3:47 PM
A very Merr Chrismas to all you hoomans out there, from Prehistoric Planet: Ice Age's Megalonyx family!
Wishing you a safe and happy holiday!
#PrehistoricPlanet #PrehistoricPlanetIceAge #paleoart #groundsloth #Christmas #meme
Wishing you a safe and happy holiday!
#PrehistoricPlanet #PrehistoricPlanetIceAge #paleoart #groundsloth #Christmas #meme
Reposted by Michael Deak
Result from the Talara tar seeps #paleostream! Like the La Brea tar pits this was Pleistocene death trap, however these fossils come from Peru so everything has a south american flavor. This piece is set at the beginning of the rainy season, with new green beginning to sprout...
December 17, 2025 at 2:52 AM
Result from the Talara tar seeps #paleostream! Like the La Brea tar pits this was Pleistocene death trap, however these fossils come from Peru so everything has a south american flavor. This piece is set at the beginning of the rainy season, with new green beginning to sprout...
Reposted by Michael Deak
Excited to announce that my second manuscript, “Fossilised Melanosomes Reveal Colour Patterning in A Sauropod Dinosaur” has been published in
@royalsociety.org !! Diplodocus scales are complex and diverse, and it turns out their color patterning was even more so. A 🧵🦕 1/26
@royalsociety.org !! Diplodocus scales are complex and diverse, and it turns out their color patterning was even more so. A 🧵🦕 1/26
December 10, 2025 at 3:14 PM
Excited to announce that my second manuscript, “Fossilised Melanosomes Reveal Colour Patterning in A Sauropod Dinosaur” has been published in
@royalsociety.org !! Diplodocus scales are complex and diverse, and it turns out their color patterning was even more so. A 🧵🦕 1/26
@royalsociety.org !! Diplodocus scales are complex and diverse, and it turns out their color patterning was even more so. A 🧵🦕 1/26
Reposted by Michael Deak
In light of @tessasaurus.bsky.social's amazing paper on paleocoloration of the MDQ Diplodocus, I would *highly* recommend those interested to check out @zhejiang0pterus.bsky.social's paleo color doc! they've done great work researching it and have been very responsive to sources I've found for it. 👇
December 10, 2025 at 6:41 PM
In light of @tessasaurus.bsky.social's amazing paper on paleocoloration of the MDQ Diplodocus, I would *highly* recommend those interested to check out @zhejiang0pterus.bsky.social's paleo color doc! they've done great work researching it and have been very responsive to sources I've found for it. 👇
Huge congrats to @tessasaurus.bsky.social et al. on this excellent paper regarding the first sauropod melanosomes! royalsocietypublishing.org/rsos/article...
Fossilized melanosomes reveal colour patterning of a sauropod dinosaur
Abstract. Integumentary fossils have improved understanding of dinosaur physiology, appearance and ecological niches. Fossil melanin and fossil melanosome
royalsocietypublishing.org
December 10, 2025 at 1:08 PM
Huge congrats to @tessasaurus.bsky.social et al. on this excellent paper regarding the first sauropod melanosomes! royalsocietypublishing.org/rsos/article...
26 years of intense debate that boarded on blood feuds and this all could have been resolved if we just cut open the hyoids of CMNH 7541.....
Incredible work!
Incredible work!
Very excited to share that our latest paper is out in Science! We show that the type specimen of Nanotyrannus—an isolated skull—is fully grown, showing that it is not a juvenile Tyrannosaurus rex but a distinct species (1/12)
www.science.org/doi/10.1126/...
www.science.org/doi/10.1126/...
www.science.org
December 4, 2025 at 7:27 PM
26 years of intense debate that boarded on blood feuds and this all could have been resolved if we just cut open the hyoids of CMNH 7541.....
Incredible work!
Incredible work!
I second this!
Very nearly done on a long review of this spectacular book, King Tyrant by @markwitton.bsky.social, published by @princetonupress.bsky.social Cannot recommend it enough, buy it now! #dinosaurs #books
December 3, 2025 at 3:01 PM
I second this!
Reposted by Michael Deak
The final, formatted version of the Zanno & @jgn-paleo.bsky.social Nanotyrannus paper is out:
Zanno, L.E., Napoli, J.G. Nanotyrannus and Tyrannosaurus coexisted at the close of the Cretaceous. Nature (2025). doi.org/10.1038/s415...
Zanno, L.E., Napoli, J.G. Nanotyrannus and Tyrannosaurus coexisted at the close of the Cretaceous. Nature (2025). doi.org/10.1038/s415...
Nanotyrannus and Tyrannosaurus coexisted at the close of the Cretaceous - Nature
A well-preserved skeleton of a nearly mature tyrannosaur from the Hell Creek Formation in Montana, USA supports the existence of a second Nanotyrannus species, Nanotyrannus lethaeus sp. nov., and vali...
doi.org
December 3, 2025 at 1:33 PM
The final, formatted version of the Zanno & @jgn-paleo.bsky.social Nanotyrannus paper is out:
Zanno, L.E., Napoli, J.G. Nanotyrannus and Tyrannosaurus coexisted at the close of the Cretaceous. Nature (2025). doi.org/10.1038/s415...
Zanno, L.E., Napoli, J.G. Nanotyrannus and Tyrannosaurus coexisted at the close of the Cretaceous. Nature (2025). doi.org/10.1038/s415...
Reposted by Michael Deak
This image is a recreation from the Late Pleistocene when this meme format was last relevant.
#PrehistoricPlanet #IceAge #coproliteposting
#PrehistoricPlanet #IceAge #coproliteposting
December 2, 2025 at 11:14 PM
This image is a recreation from the Late Pleistocene when this meme format was last relevant.
#PrehistoricPlanet #IceAge #coproliteposting
#PrehistoricPlanet #IceAge #coproliteposting