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Zach

@reallyoldfish.bsky.social
575 followers 627 following 335 posts

3rd year PhD candidate in the Friedman Lab at the University of Michigan. Volunteer @ Carnegie Museum of Natural History. Pitt alum. Cat dad. Opinions my own. Fan of fishes, particularly extinct ones

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Zach @reallyoldfish.bsky.social · 04/10/2026
Massive outbreak of Northern Walkingsticks (Diapheromera femorata) at Cowan’s Gap State Park this weekend. Tons of mating pairs. Probably one of the most insane things I’ve ever seen.
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Zach @reallyoldfish.bsky.social · 19/09/2026
Not one person understands how evil she is
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Zach @reallyoldfish.bsky.social · 05/09/2026
A sign of the end of summer. Dog-day cicadas being increasingly easy to find on the ground. They’re finishing up their grand chorus before the eventual silence of winter settles in.
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Zach @reallyoldfish.bsky.social · 25/08/2026
First scan of the semester looks promising. Sometimes fish look like fish!! Gzhelian of the Appalachian Basin.
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Zach @reallyoldfish.bsky.social · 16/08/2026
Rule #1: don’t overtighten your lugs, or you’ll end up like me!
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Zach @reallyoldfish.bsky.social · 22/07/2026
Windy day in the Pioneer Mountains of Montana. Good views and workout (and plants, see the Lewisia pygmaea photo) before my last week of teaching ecosystem science out here. Bonus rip-up clasts in quartzite of the Mesoproterozoic Missoula Group.
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Zach @reallyoldfish.bsky.social · 15/07/2026
Fieldwork in Bears Ears in 2023 was my first experience doing work “out West” and it fundamentally shifted my perspective on both paleontology and society more broadly. It is a beautiful, fragile place that needs to be protected. Not to mention that it is on fire right now, too (100k+ acres)
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Zach @reallyoldfish.bsky.social · 15/07/2026
The 90% reduction of Bears Ears National Monument and Grand Staircase-Escalante NM is a massive loss for science, indigenous communities, and the American public more broadly.
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Zach @reallyoldfish.bsky.social · 24/06/2026
So thank you for taking care of me when I needed it, guiding me back to the right path when I went astray, and teaching me about the world. I’ll never be able to repay all who have given to me, but I’ll do my best to pay it forward.
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Zach @reallyoldfish.bsky.social · 24/06/2026
Between its hills and in the buildings built upon them I learned the basis of biology, geology, and justice. At every turn someone was there to help me out when I was down on my luck. The folks here also haven’t bit their tongue when they’ve seen me falling out of line.
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Zach @reallyoldfish.bsky.social · 24/06/2026
An ode to Pittsburgh: skip if you dislike sappy threads I’ve been around the world and the country but nowhere will compare to sw Pennsylvania. This place, these people, have a spot in my heart that will not soon be replaced.
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Zach @reallyoldfish.bsky.social · 13/06/2026
Dr. Richard Lund spearheaded the work on this deposit and described much of the vertebrate fauna, the ecosystem, and geology. Pictured below is Discoserra pectinodon, an iconic ray-finned fish from the deposit that has been the subject of extensive study and debate (watch this space :p)
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Zach @reallyoldfish.bsky.social · 13/06/2026
Happy #fossilfriday ! Today @hadeelsaad.bsky.social and I began the long-haul process of driving 600 specimens from Ann Arbor, Michigan, to Missoula, Montana. These specimens are from the famous Bear Gulch lagerstätte (located in Montana).
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Zach @reallyoldfish.bsky.social · 22/05/2026
For #fossilfriday I have Amphicentrum jurgenai, from the late Carboniferous locality Kinney Brick Quarry. The late Paleozoic was full of deep bodied animals, including platysomids and the enigmatic Platysella. Frustratingly, much of their anatomy remains a mystery, but watch this space ;)
Picture of a fossil fish (Amphicentrum jurgenai) preserved on a slab of dark tan shale.
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Zach @reallyoldfish.bsky.social · 06/05/2026
Very eastern North American pull of animals this evening. The great horned owl chick’s name is Baby Man.
Common raccoon (Procyon lotor) sitting in the crotch of a cherry tree, viewed from below.Bubo virginianus (great horned owl) chick sitting on dead oak wood in a forest.
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Zach @reallyoldfish.bsky.social · 03/05/2026
Beautiful day in the neighborhood. Thanks Pittsburgh for showing up to support us runners 🫶
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Zach @reallyoldfish.bsky.social · 02/05/2026
different fossil Friday this week. huge congrats to @athenavohs.bsky.social for successfully completing her masters! good luck at CU Boulder!! your passion will carry you far. Athena works on condylarths (enigmatic Paleogene mammals) so I’ve included one here (Anisonchus— read alt text!)
Anisonchus fortunatus, a condylarth discovered in a drill core from Louisiana.
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Zach @reallyoldfish.bsky.social · 24/04/2026
Happy #fossilfriday! @hadeelsaad.bsky.social , Emily Hillan, and I spent the past week in the Appalachian Basin collecting in the Carboniferous. We found a lot of great stuff but the best thing we got was a fossil xiphosuran, Euproops! Very uncommon here. Time to organize it all!
cf Euproops danae Hadeel Saad sitting at a table with a large number of fossils in front of hercf Euproops danae, in the field
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Zach @reallyoldfish.bsky.social · 24/04/2026
Happy #fossilfriday! @hadeelsaad.bsky.social , Emily Hillan, and I spent the past week in the Appalachian Basin collecting in the Carboniferous. We found a lot of great stuff but the best thing we got was a fossil xiphosuran, Euproops! Very uncommon here. Time to organize it all!
cf Euproops danae Hadeel Saad sitting at a table with a large number of fossils in front of hercf Euproops danae, in the field
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Zach @reallyoldfish.bsky.social · 22/04/2026
Insect people, WTF is going on over here? Found in Allegheny County PA. Suburb/forest edge. Large one is Lytta aenea. Small one was biting it? But it wasn’t really moving? So confused.
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Zach @reallyoldfish.bsky.social · 12/04/2026
All from today. The world is waking up.
Nerodia sepidon (common water snake) lying on a patch of moss surrounded by emerging leaves of herbaceous plants and  dead grass Noturus stigmosus (Northern madtom) lying on the bottom of a water-filled plastic box. In left lateral viewTwo blunt lobed hepatica flowers emerging from muddy ground. There are sporadic dead leaves of oak surrounding the hepatica, and a large log towards the top of the picture
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Zach @reallyoldfish.bsky.social · 10/04/2026
For #fossilfriday I have the holotype of Kalops monophrys, CM 27372. Kalops is a classic “palaeoniscoid” from Bear Gulch , a Mississippian lagerstätte in central Montana. While squished, it’s undeniably a gorgeous fossil.
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Zach @reallyoldfish.bsky.social · 08/04/2026
Cat shots from the past two days. God I love this creature
Tabby cat looking down at you with slight discontentTabby cat looking out from under a blue and white comforter
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Zach @reallyoldfish.bsky.social · 01/04/2026
While bowfin are represented by predatory marine taxa, the weirdest members of the holostean clade here are macrosemiids, a group of stem gar trying to be wrasses. The living clade of holosteans is limited to just nine taxa— without the fossil record, strange forms such as this would be lost.
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Zach @reallyoldfish.bsky.social · 29/03/2026
Gorgeous, colored up male Etheostoma caeruleum from the Huron River today. Picture credit: James Andrews.
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Zach @reallyoldfish.bsky.social · 28/03/2026
I am now a PhD candidate, which means that my cat can continue to be unemployed. Thanks to everyone that made it possible. This has by no means been a solo effort. If you’ve helped me, you know who you are. You’re the best.
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Zach @reallyoldfish.bsky.social · 22/03/2026
How can you ignore it any longer?
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Zach @reallyoldfish.bsky.social · 06/03/2026
Taking some time to reflect on my progress as I inch closer to my qualifying exam. I think it’s been easy for me to connect to my study system when it is *literally* in my backyard. The fish I’m describing comes from the Birmingham Shale, which is close to the surface at my parents house
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Zach @reallyoldfish.bsky.social · 11/02/2026
Do not look away.
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Zach @reallyoldfish.bsky.social · 07/02/2026
posin
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Zach @reallyoldfish.bsky.social · 05/02/2026
Holy WOW I love my cat
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Zach @reallyoldfish.bsky.social · 30/01/2026
Another day, another jaw Gzhelian, Appalachian Basin(nr Pittsburgh) 303-298 Ma
Lower jaw of Carboniferous ray finned fish in a CT scanner
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Zach @reallyoldfish.bsky.social · 26/01/2026
Big week for me this week. Posting cat pictures to get me, and maybe you , too, through your Monday.
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Zach @reallyoldfish.bsky.social · 25/01/2026
A brief break in the doom. The moment my cat, Bergamot, understood where the laser came from
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Zach @reallyoldfish.bsky.social · 14/01/2026
Away from the lab today, so strat time. Got a copy for cheap from the fourth Pennsylvania Geologic Survey, which is both aesthetically pleasing and vital to my work. I also dug into some midcontinent strat for a big project..
Picture of the first inside cover of an old book showing both titles, text, and old library stampsPicture of a page in an old book showing black and white photos and text
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Zach @reallyoldfish.bsky.social · 29/12/2025
Great surprise today at the Carnegie Museum of Natural History today. Unbeknownst to me, a Diplichnites trackway I collected from my backyard when I was 12 and donated when I was 19 is now on display in the new Stories Week Keep gallery. What an honor.
A picture of fossils in a display case
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Zach @reallyoldfish.bsky.social · 29/12/2025
This is the kind of car I want to drive someday
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Zach @reallyoldfish.bsky.social · 25/12/2025
This Christmas, remember that Jesus was a refugee and unhoused. Artist credit: Kelly Latimore
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Zach @reallyoldfish.bsky.social · 20/12/2025
The most scan that has ever existed.
Picture of a ct scan of a concretion, with a fossil fish jaw at the center
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Zach @reallyoldfish.bsky.social · 20/12/2025
What an incredible opportunity it was to drive the HEX beamline at NSLS II (Brookhaven National Labs) with @friedmanlab.bsky.social , @james-v-andrews.bsky.social , and others. We gathered a TON of great 🐟 data; I am hopeful that what we gathered will lead to more fishy discoveries.
The author (Zach Lyons-Weiler) sitting in a chair in front of a number of computer screens at the HEX beamline at NSLS-II at Brookhaven National Laboratory.James Andrews sitting in a chair in front of a number of computer screens at the HEX beamline at NSLS-II at Brookhaven National Laboratory.The author (left) and Matt Friedman (right) traveling to the beamline. Matt Friedman is using a trike share, an efficient mode of transport around a facility as large as NSLS-II
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Zach @reallyoldfish.bsky.social · 15/12/2025
They’ve been getting archosaurs (even if it was just an accident) since the Mesozoic. Source pub: journals.plos.org/plosone/arti...
A fossil of Aspidorhynchus and Rhamphorhynchus from the Solnhofen Plattenkalk
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Zach @reallyoldfish.bsky.social · 13/12/2025
For #fossilfriday I want to post a fossil fish jaw that actually looks like a fossil fish jaw. Gzhelian, Appalachian Basin.
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Zach @reallyoldfish.bsky.social · 12/12/2025
Most normal cargo
3D print of a temnospondyl skull. Placed on top of a cardboard box on a car seat.
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Zach @reallyoldfish.bsky.social · 12/12/2025
Bathysaurus, an aulopiform. How the mighty have fallen.
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Zach @reallyoldfish.bsky.social · 09/12/2025
A mysterious animal, the crossopterytian
Polypterus senegalus model generated via CT segmentation software
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Zach @reallyoldfish.bsky.social · 08/12/2025
Acipenser ❌ Neophanerorhynchus ✅ United by the presence of SNOUT
Acipenser fulvescens (lake sturgeon) at the Toledo Aquarium
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Zach @reallyoldfish.bsky.social · 05/12/2025
Wow! Fossil Friday is already upon us! Guess what! I have another fish fossil! Who would have guessed it! Dentary, Actinopterygii indet Chanute Shale, Pennsylvanian, KS, USA
Picture of a person holding a fossil fish mandible in a dark grey concretion
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Zach @reallyoldfish.bsky.social · 22/11/2025
If you can tell me what this is I will maybe give you 1 billion dollars #fossifriday.
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Zach @reallyoldfish.bsky.social · 17/11/2025
Humbled and honored to be able to present my work at this year’s iteration of SVP, and to be provided funds by the society to support my travel. Great views from the plane back yesterday, including the St. Clair Delta. Back in the states now, ready to scan more fish !
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Zach @reallyoldfish.bsky.social · 09/11/2025
A bit of a pleasant surprise to wake up to actual snow this morning. Hopefully it stays this way this winter!
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