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Stephen Chester

@purgatoriidae

Paleontologist at Brooklyn College, The Graduate Center, CUNY, and NYCEP Curatorial Affiliate / Research Associate at AMNH, DMNS, FLMNH, and YPM https://www.stephenchesterpaleontology.com/

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25.02.2025
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Latest posts by Stephen Chester @purgatoriidae

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Tiny teeth found in Colorado deepen the debate over primate origins A sediment-washing “bubbler” helped researchers recover 65.5-million-year-old teeth that illuminate how early primate relatives spread after the mass extinction.

Scientists just found Purgatorius, the world’s oldest primate, lived much farther south than previously known.

The data suggest the tiny critter spread quickly after the asteroid that killed the dinos, migrating southward across the US.

#Paleontology

🧪🧪

New for #NatGeo

03.03.2026 15:27 👍 34 🔁 10 💬 1 📌 0
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Brooklyn College Paleontologist Stephen Chester and Colleagues Reveal New Clues About Early Primate Evolution - Brooklyn College Findings help clarify the biogeographic history of the earliest primate relatives and highlight the importance of continued fossil exploration in understudied regions.

A study led by paleontologist and Brooklyn College / @thegraduatecenter.bsky.social Stephen Chester (@purgatoriidae.bsky.social) is shedding light on how the earliest known primate relatives evolved and spread across North America after the extinction of the dinosaurs.

03.03.2026 16:16 👍 2 🔁 1 💬 1 📌 0
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Southernmost occurrence of Purgatorius sheds light on the biogeographic history and diversification of the earliest primate relatives Fossils of the earliest known euarchontan mammals, purgatoriid plesiadapiforms, first appear during the aftermath of the Cretaceous/Paleogene mass extinction. The oldest and most basally branching ...

Our study on the southernmost occurrence of Purgatorius was published today in the Journal of Vertebrate Paleontology! Thanks to all the Brooklyn College undergraduates and DMNS interns who found these needles in a haystack of fossiliferous sediment!

www.tandfonline.com/doi/full/10....

03.03.2026 15:01 👍 18 🔁 6 💬 0 📌 1
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We had a great time at commencement at Lincoln Center last night! Congratulations to Dr. Jordan Crowell and to all our 2025 CUNY Graduate Center graduates!

11.06.2025 13:50 👍 11 🔁 3 💬 1 📌 0
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Basicranial evidence suggests picrodontid mammals are not stem primates | Biology Letters The Picrodontidae from the middle Palaeocene of North America are enigmatic placental mammals that were allied with various mammalian groups but are generally now considered to have close affinities t...

Basicranial evidence suggests picrodontid mammals are not stem primates royalsocietypublishing.org/doi/10.1098/...

23.05.2025 19:58 👍 9 🔁 3 💬 0 📌 0
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Yesterday's senior seminar presentations were excellent!Congratulations to all our graduating seniors!

22.05.2025 13:31 👍 3 🔁 0 💬 0 📌 0
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Congratulations to Nidhi Mahadevan! She received first place in STEM at the 2025 Macaulay Honors College Outstanding Undergraduate Research Awards ceremony last week for her work on Purgatorius lower molars using three-dimensional geometric morphometrics. Well done, Nidhi!

12.05.2025 16:31 👍 3 🔁 0 💬 0 📌 0
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Congratulations to Jordan Crowell @crowelljw.bsky.social on a successful doctoral dissertation defense at the AMNH yesterday!!! A special thank you goes to Eric Delson, Chris Gilbert, and John Wible for serving on his committee!

05.04.2025 15:55 👍 13 🔁 1 💬 1 📌 0
A photo of the fossilized remains of Prestosuchus on display in the Museum. The animal is quadrupel and low to the ground. It has a dinosaur-like skull.

A photo of the fossilized remains of Prestosuchus on display in the Museum. The animal is quadrupel and low to the ground. It has a dinosaur-like skull.

Meet Prestosuchus chiniquensis. It lived in what’s now Brazil some 210 million years ago. Although it was a large animal with big claws & a huge head with sharp-toothed jaws, it wasn't a dinosaur—it's actually a close relative of crocodylomorphs.

Photo: © AMNH

04.04.2025 17:19 👍 121 🔁 13 💬 7 📌 2

Happy Fossil Friday! Today I was invited to speak to my son's class about paleontology. He interrupted me when I simply referred to one of my 3D prints as a primate fossil. He wanted me to tell the class the GENUS. He is 2. 😂

21.03.2025 20:25 👍 6 🔁 0 💬 0 📌 0
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I enjoyed the opportunity to present the diamond open access, community owned, PaleoAnthropology journal and discuss the situation at the Journal of Human Evolution at the NYCEP seminar, City University of New York last week!

Thank you to Larissa Swedell for the invitation.

13.03.2025 20:26 👍 18 🔁 5 💬 0 📌 0
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Stephen Chester and Team Unlock Secrets of Mysterious 62-Million-Year-Old Mammal - Brooklyn College New Findings Illuminate Ancient Species and its Evolutionary Connections to Modern-Day Humans.

Anthropology + @thegraduatecenter.bsky.social's @purgatoriidae.bsky.social worked with a team of researchers to uncover fascinating new details about Mixodectes pungens, a long-mysterious mammal that roamed North America in the early Paleocene, just after the extinction of the dinosaurs.

14.03.2025 18:34 👍 8 🔁 3 💬 1 📌 0
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Early mammals were all one color, study suggests Their fur may not have been flashy, but it served a purpose.

Our early mammal ancestors had drab boring fur colors.

Why make yourself all bright and shiny when you're only coming out at night, to avoid those huge dinosaurs?

Exciting new research on fossil melanosomes from Matthew Shawkey & team! My thoughts for @popsci.com:

www.popsci.com/science/earl...

13.03.2025 20:18 👍 43 🔁 5 💬 0 📌 0

Our new paper led by Jordan Crowell on the oldest known plesiadapiform cranium is out! If you're in Baltimore, set your alarm and check out more cool work from our lab at Jordan's 8:15 AM talk on Friday #AABA2025

www.sciencedirect.com/science/arti...

13.03.2025 14:25 👍 3 🔁 0 💬 0 📌 0
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Stephen Chester and Team Unlock Secrets of Mysterious 62-Million-Year-Old Mammal New findings illuminate an ancient species and its evolutionary connections to modern-day humans.

A new study by Prof. Stephen Chester uncovered surprising new details about Mixodectes pungens, a long-mysterious mammal that roamed North America just after the extinction of the dinosaurs www.gc.cuny.edu/news/stephen... @purgatoriidae.bsky.social

11.03.2025 14:07 👍 8 🔁 2 💬 0 📌 1
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Mixodectes (foreground) was about three pounds and had an omnivorous diet that included leaves. It appears to have occupied a unique ecological niche in trees shared with smaller plesiadapiforms like Torrejonia wilsoni (background) 62 million years ago. Amazing illustration by Andrey Atuchin!

11.03.2025 15:47 👍 3 🔁 1 💬 0 📌 0
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New remarkably complete skeleton of Mixodectes reveals arboreality in a large Paleocene primatomorphan mammal following the Cretaceous-Paleogene mass extinction - Scientific Reports Scientific Reports - New remarkably complete skeleton of Mixodectes reveals arboreality in a large Paleocene primatomorphan mammal following the Cretaceous-Paleogene mass extinction

Excited to share our new paper on the most complete mixodectid fossil ever discovered! Phylogenetic results support Mixodectes as most closely related to primatomorphans (primates and colugos) among mammals.

www.nature.com/articles/s41...

11.03.2025 15:38 👍 26 🔁 11 💬 1 📌 1
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Case Closed for Dino Killer? Paleontologists find evidence that dinos were alive and well just before asteroid impact

www.science.org/content/arti...

28.02.2025 16:46 👍 1 🔁 0 💬 0 📌 0
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Happy Fossil Friday! I was happy to see the admittedly ugly but cool ceratopsian horn I picked up 13 centimeters below the pollen-defined K-Pg boundary many moons ago is now on permanent display at the Yale Peabody Museum!

28.02.2025 16:46 👍 2 🔁 0 💬 1 📌 0
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I’m back to my old stomping grounds with Tyler Lyson and team at the Yale Peabody Museum today! I first met Tyler in Elisabeth Vrba’s Paleontology and Evolutionary Theory course in 2006, and we've been collaborating ever since…

27.02.2025 19:25 👍 2 🔁 0 💬 0 📌 0
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A Day in the Badlands: A 52 Million-Year-Old Safari Adventure with Amy Chew, Christopher Gilbert, Ross Secord, and Stephen Chester Illustrations by Jenn Paul • Book design by Aaron Sutherlen About the Badlands Fossils -- This story tells about the fossils of anc...

Check out our children’s book on paleontology and life in the Eocene! This work stems from our NSF funded research on mammalian response to the Early Eocene Climatic Optimum in the Wind River and Bighorn basins of Wyoming.
digitalcommons.unl.edu/zeabook/165/

26.02.2025 16:30 👍 15 🔁 6 💬 1 📌 0

Amazing illustration of early Paleocene biotic recovery in the Denver Basin by @olorotitan.bsky.social

26.02.2025 00:01 👍 5 🔁 0 💬 0 📌 0
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Hi, I’m Stephen and I study how primates and other mammals evolved following the extinction of the dinosaurs. I run the Mammalian Evolutionary Morphology Laboratory (“MEML”) at Brooklyn College and look forward to sharing our discoveries with you!

25.02.2025 23:53 👍 7 🔁 1 💬 1 📌 0