Jack Stack
@jackstack.bsky.social
Trophy husband, PhD vertebrate paleontologist. 0 time rank 1 wow PVP player. I also write about the history of fishes: https://fishhistory.substack.com/. He/him
Can you spot the predator here?
January 10, 2026 at 5:09 PM
Can you spot the predator here?
Jump scare at the library today
January 9, 2026 at 9:56 PM
Jump scare at the library today
Ideal writing conditions
January 6, 2026 at 7:21 PM
Ideal writing conditions
Sauropod dinosaurs are easily the coolest land animals ever. Not even sure how it’s possible to have a giant plant processing plant be alive, but they did it!
January 1, 2026 at 1:53 AM
Sauropod dinosaurs are easily the coolest land animals ever. Not even sure how it’s possible to have a giant plant processing plant be alive, but they did it!
Love that fish with horrible teeth are becoming my research program. Had to share Dipteronotus ornatus, Middle Triassic of Switzerland. Illustration by Tony Bürgun.
December 31, 2025 at 6:27 PM
Love that fish with horrible teeth are becoming my research program. Had to share Dipteronotus ornatus, Middle Triassic of Switzerland. Illustration by Tony Bürgun.
Invertebrate paleo people: can anyone ID this? Found in glacial till in Michigan and I am not sure what this is.
December 24, 2025 at 9:24 PM
Invertebrate paleo people: can anyone ID this? Found in glacial till in Michigan and I am not sure what this is.
Time to learn about teleosts!
December 24, 2025 at 1:20 AM
Time to learn about teleosts!
My great grandfather’s scythe, very cool artifact at the family farm.
December 23, 2025 at 8:01 PM
My great grandfather’s scythe, very cool artifact at the family farm.
Found in my fossil collection. Bit of a challenge but anyone want to guess what this is?
December 23, 2025 at 2:56 AM
Found in my fossil collection. Bit of a challenge but anyone want to guess what this is?
Draft from a paper I’m working on… the triangle at least a hundred species in it btw :)
December 16, 2025 at 7:49 PM
Draft from a paper I’m working on… the triangle at least a hundred species in it btw :)
How it feels to cite yourself.
December 16, 2025 at 7:46 PM
How it feels to cite yourself.
Excited to talk about zoology with prospective students for natural sciences day at Bowie State! Had to get out the T-Rex of course.
December 10, 2025 at 3:57 PM
Excited to talk about zoology with prospective students for natural sciences day at Bowie State! Had to get out the T-Rex of course.
How can you not love phytosaurs? Reconstruction by Jeff Martz.
December 3, 2025 at 5:09 PM
How can you not love phytosaurs? Reconstruction by Jeff Martz.
Appreciate Kate Bemis and the Smithsonian for hosting me today, had a ton of fun looking at recently dead fishes
December 2, 2025 at 9:43 PM
Appreciate Kate Bemis and the Smithsonian for hosting me today, had a ton of fun looking at recently dead fishes
Appreciate Kate Bemis and the Smithsonian for hosting me today, had a ton of fun looking at recently dead fishes
December 2, 2025 at 9:40 PM
Appreciate Kate Bemis and the Smithsonian for hosting me today, had a ton of fun looking at recently dead fishes
In light of recent discussions around academia, worth sharing how I start each class. In a productive learning community, everyone needs to be treated with respect and as a human being.
December 1, 2025 at 5:35 PM
In light of recent discussions around academia, worth sharing how I start each class. In a productive learning community, everyone needs to be treated with respect and as a human being.
Ray-finned fish taxonomy
November 29, 2025 at 7:50 PM
Ray-finned fish taxonomy
Yeah, no. I spent ten years studying and working for this title. Ten years of low pay and hard work to become an expert in my field. As my namesake and grandfather (the first Dr. Jack Stack) would say, my first name is doctor.
November 24, 2025 at 5:56 PM
Yeah, no. I spent ten years studying and working for this title. Ten years of low pay and hard work to become an expert in my field. As my namesake and grandfather (the first Dr. Jack Stack) would say, my first name is doctor.
Reading about Pennsylvanian fishes, absolute horror show from my master's advisor dissertation (Michael Gottfried, 1993).
November 21, 2025 at 3:11 PM
Reading about Pennsylvanian fishes, absolute horror show from my master's advisor dissertation (Michael Gottfried, 1993).
Reading about Permian ray-finned fishes and I would like to speak with the manager. Who gave Dorypterus the permission to be like this? From Westoll (1931).
November 18, 2025 at 4:12 PM
Reading about Permian ray-finned fishes and I would like to speak with the manager. Who gave Dorypterus the permission to be like this? From Westoll (1931).
21) Finally, the result that will get fruit thrown at me. The phylogenetic classification of living ray-finned fishes and a hundred years of precedent says that bichirs and reedfish are the earliest diverging lineage of living ray-finned fishes. Might I gently suggest an alternative?
November 18, 2025 at 4:22 AM
21) Finally, the result that will get fruit thrown at me. The phylogenetic classification of living ray-finned fishes and a hundred years of precedent says that bichirs and reedfish are the earliest diverging lineage of living ray-finned fishes. Might I gently suggest an alternative?
18) I also took a look at Brachydegma, which thankfully was re-described in great detail by Argyiou, Giles, and Friedman while I was in the planning stages of the project. Although I arrived at a slightly different placement, I can't emphasize enough how much that work improved my own.
November 18, 2025 at 4:22 AM
18) I also took a look at Brachydegma, which thankfully was re-described in great detail by Argyiou, Giles, and Friedman while I was in the planning stages of the project. Although I arrived at a slightly different placement, I can't emphasize enough how much that work improved my own.
15) But wait, there's more! I included some other problematic taxa that look out of place. Like Coccolepis here. Coccolepis, and coccolepids, are Jurassic-Cretaceous fishes that look startlingly like Paleozoic actinopterygians. But, there is a debate as to their relationships.
November 18, 2025 at 4:22 AM
15) But wait, there's more! I included some other problematic taxa that look out of place. Like Coccolepis here. Coccolepis, and coccolepids, are Jurassic-Cretaceous fishes that look startlingly like Paleozoic actinopterygians. But, there is a debate as to their relationships.