Tristan J. Stock
@archelosaurian.bsky.social
Master of Science in Paleontology working on fossil Archelosauria. Currently studying Miocene sea turtles at the Los Angeles Natural History Museum. Enjoys talking about Reptiles (including Birds!), SpecEvo, and general nerd stuff.
Thanks to everyone who came by my #2025SVP poster yesterday! Very happy to talk about a large chunk of my master’s thesis.
Thank you to my supervisor James Parham, as well as @medenadragon.bsky.social and @wolpard.bsky.social for their artwork which helped to bring our animal to life.
Thank you to my supervisor James Parham, as well as @medenadragon.bsky.social and @wolpard.bsky.social for their artwork which helped to bring our animal to life.
November 15, 2025 at 7:25 AM
Thanks to everyone who came by my #2025SVP poster yesterday! Very happy to talk about a large chunk of my master’s thesis.
Thank you to my supervisor James Parham, as well as @medenadragon.bsky.social and @wolpard.bsky.social for their artwork which helped to bring our animal to life.
Thank you to my supervisor James Parham, as well as @medenadragon.bsky.social and @wolpard.bsky.social for their artwork which helped to bring our animal to life.
Unfortunately for me, their #Pliosauruskevani wasn’t satisfied with schoolchildren anymore, and decided to go for something bigger.
November 11, 2025 at 2:27 PM
Unfortunately for me, their #Pliosauruskevani wasn’t satisfied with schoolchildren anymore, and decided to go for something bigger.
The #DorsetMuseum is really great. They have original notebooks from Mary Anning and several famous holotypes from the area out for people to see.
November 11, 2025 at 2:27 PM
The #DorsetMuseum is really great. They have original notebooks from Mary Anning and several famous holotypes from the area out for people to see.
Me a week ago: “It’s a whole family of T. rex. How wholesome.”
Me today: “Little guy is so screwed.”
#NHMLA #LACM #JordanTheropod #Nanotyrannus?
Me today: “Little guy is so screwed.”
#NHMLA #LACM #JordanTheropod #Nanotyrannus?
November 1, 2025 at 7:24 PM
Me a week ago: “It’s a whole family of T. rex. How wholesome.”
Me today: “Little guy is so screwed.”
#NHMLA #LACM #JordanTheropod #Nanotyrannus?
Me today: “Little guy is so screwed.”
#NHMLA #LACM #JordanTheropod #Nanotyrannus?
The antorbital fossa is also narrow and shallow, which suggests (if it is Nano) an N. lancensis species identification.
Unfortunately the premaxilla is poorly preserved so we can’t say much about the premaxillary teeth. Nano has serrated premaxillary teeth, Rex (and other tyrannosaurids) do not.
Unfortunately the premaxilla is poorly preserved so we can’t say much about the premaxillary teeth. Nano has serrated premaxillary teeth, Rex (and other tyrannosaurids) do not.
November 1, 2025 at 4:46 PM
The antorbital fossa is also narrow and shallow, which suggests (if it is Nano) an N. lancensis species identification.
Unfortunately the premaxilla is poorly preserved so we can’t say much about the premaxillary teeth. Nano has serrated premaxillary teeth, Rex (and other tyrannosaurids) do not.
Unfortunately the premaxilla is poorly preserved so we can’t say much about the premaxillary teeth. Nano has serrated premaxillary teeth, Rex (and other tyrannosaurids) do not.
LACM 28471, the holotype of “Stygivenator” and possibly the only Nanotyrannus on display along the west coast. Turtle-loving human for scale.
It’s very fragmentary (what you see is what you get) so the ID is tentative, but it lacks a subnarial foramen, which is a synapomorphy of Nano. (Circle)
It’s very fragmentary (what you see is what you get) so the ID is tentative, but it lacks a subnarial foramen, which is a synapomorphy of Nano. (Circle)
November 1, 2025 at 4:46 PM
LACM 28471, the holotype of “Stygivenator” and possibly the only Nanotyrannus on display along the west coast. Turtle-loving human for scale.
It’s very fragmentary (what you see is what you get) so the ID is tentative, but it lacks a subnarial foramen, which is a synapomorphy of Nano. (Circle)
It’s very fragmentary (what you see is what you get) so the ID is tentative, but it lacks a subnarial foramen, which is a synapomorphy of Nano. (Circle)
Took a really, really good specimen (in a public museum!) and experts willing to do the hard work to prove its validity. Congrats to the authors for this cool discovery.
Here’s to the inevitable future workers trying to weed out whatever Lancian small tyrannosaurs are Nano and which are T. rex.
Here’s to the inevitable future workers trying to weed out whatever Lancian small tyrannosaurs are Nano and which are T. rex.
October 30, 2025 at 5:50 PM
Took a really, really good specimen (in a public museum!) and experts willing to do the hard work to prove its validity. Congrats to the authors for this cool discovery.
Here’s to the inevitable future workers trying to weed out whatever Lancian small tyrannosaurs are Nano and which are T. rex.
Here’s to the inevitable future workers trying to weed out whatever Lancian small tyrannosaurs are Nano and which are T. rex.
Wonder what’s in here? If you’re at #2025SVP and would like to know, drop my by Friday poster in the Turts and Crocs space, board B301.
I will be presenting my graduate research on Pan-Cheloniids, including revealing a new morphotype of Cenozoic sea turtle that lived surprisingly recently.
I will be presenting my graduate research on Pan-Cheloniids, including revealing a new morphotype of Cenozoic sea turtle that lived surprisingly recently.
October 29, 2025 at 7:40 PM
Wonder what’s in here? If you’re at #2025SVP and would like to know, drop my by Friday poster in the Turts and Crocs space, board B301.
I will be presenting my graduate research on Pan-Cheloniids, including revealing a new morphotype of Cenozoic sea turtle that lived surprisingly recently.
I will be presenting my graduate research on Pan-Cheloniids, including revealing a new morphotype of Cenozoic sea turtle that lived surprisingly recently.
Watch until the end.
October 24, 2025 at 4:27 PM
Watch until the end.
Been a good couple of days for extinct armored Archelosaurians. Giant (~4m) terrestrial hypercarnivorous crocodyliform Kostensuchus atrox living in a high paleolatitude environment at the end of the Cretaceous. Many surprises in that sentence. Also, epic animation!
journals.plos.org/plosone/arti...
journals.plos.org/plosone/arti...
August 27, 2025 at 7:55 PM
Been a good couple of days for extinct armored Archelosaurians. Giant (~4m) terrestrial hypercarnivorous crocodyliform Kostensuchus atrox living in a high paleolatitude environment at the end of the Cretaceous. Many surprises in that sentence. Also, epic animation!
journals.plos.org/plosone/arti...
journals.plos.org/plosone/arti...
What an incredible animal. It looks almost like if a toddler drew an ankylosaur and wouldn’t stop giving it spikes. Very interested in what else comes out of these beds in the future.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
August 27, 2025 at 4:17 PM
What an incredible animal. It looks almost like if a toddler drew an ankylosaur and wouldn’t stop giving it spikes. Very interested in what else comes out of these beds in the future.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Needless to say, what adaptations hadrosaurs employed, whether behavioral or anatomical, is a question I'm not sure we'll ever be equipped to answer. However, it does fuel a lot of interesting speculation on what were clearly very successful animals.
February 22, 2025 at 11:19 AM
Needless to say, what adaptations hadrosaurs employed, whether behavioral or anatomical, is a question I'm not sure we'll ever be equipped to answer. However, it does fuel a lot of interesting speculation on what were clearly very successful animals.
There's no adequate model for this amongst extant tetrapods. Extant archosaurs have much shorter incubation times, all large mammals carry young internally, and the largest members of both groups have young born precocial and ready to move and feed immediately after birth.
February 22, 2025 at 11:19 AM
There's no adequate model for this amongst extant tetrapods. Extant archosaurs have much shorter incubation times, all large mammals carry young internally, and the largest members of both groups have young born precocial and ready to move and feed immediately after birth.
These are HUGE endothermic animals that need to forage in a huge area, and being restricted to one area imposes on typical herbivorous animal feeding strategies. For example, how feasible is it to migrate long distances to follow new growth if your whole herd is stuck in one spot for >8 months?
February 22, 2025 at 11:19 AM
These are HUGE endothermic animals that need to forage in a huge area, and being restricted to one area imposes on typical herbivorous animal feeding strategies. For example, how feasible is it to migrate long distances to follow new growth if your whole herd is stuck in one spot for >8 months?
Given that Maiasaura reaches ~250-500 kg after around a year, this implies an additional few months until the young can leave the nest. So the total amount of time parents are stuck at the nest site is likely 8-10 months, maybe more, and that's not counting even further post-nesting parental care.
February 22, 2025 at 11:19 AM
Given that Maiasaura reaches ~250-500 kg after around a year, this implies an additional few months until the young can leave the nest. So the total amount of time parents are stuck at the nest site is likely 8-10 months, maybe more, and that's not counting even further post-nesting parental care.
We also know from embryonic growth-line counts in the teeth of embryonic #Hypacrosaurus suggest a minimum incubation period of 171 days or almost 6 months! That is a long time for a multi-ton herbivore to stay in one spot, and that's just for the young to be able to hatch.
February 22, 2025 at 11:19 AM
We also know from embryonic growth-line counts in the teeth of embryonic #Hypacrosaurus suggest a minimum incubation period of 171 days or almost 6 months! That is a long time for a multi-ton herbivore to stay in one spot, and that's just for the young to be able to hatch.
Hadrosaur nesting colonies, such as those reported for Maiasaura in the Two Medicine, imply that some hadrosaur species built large communal nesting sites used by dozens of breeding individuals at once, each protecting around three dozen eggs in a nest, with direct evidence of post-hatching care.
February 22, 2025 at 11:19 AM
Hadrosaur nesting colonies, such as those reported for Maiasaura in the Two Medicine, imply that some hadrosaur species built large communal nesting sites used by dozens of breeding individuals at once, each protecting around three dozen eggs in a nest, with direct evidence of post-hatching care.
Something that I don't think is discussed enough in #paleontology circles is just how much parental investment is seen in #hadrosaurs. Cause, like, they're doing quite a lot of work compared to what is typical of all other #archosaurs.
#Dinosaurs #Maiasaura
#Dinosaurs #Maiasaura
February 22, 2025 at 11:19 AM
Something that I don't think is discussed enough in #paleontology circles is just how much parental investment is seen in #hadrosaurs. Cause, like, they're doing quite a lot of work compared to what is typical of all other #archosaurs.
#Dinosaurs #Maiasaura
#Dinosaurs #Maiasaura
Given what we know about sloth phylogeny, there is a non-zero chance that megathere sloth reproduction also involved females advertising their availability with screams, followed by a stampede of testosterone-fueled males rushing towards her.
A terrifying potential experience for everything else.
A terrifying potential experience for everything else.
January 19, 2025 at 11:19 PM
Given what we know about sloth phylogeny, there is a non-zero chance that megathere sloth reproduction also involved females advertising their availability with screams, followed by a stampede of testosterone-fueled males rushing towards her.
A terrifying potential experience for everything else.
A terrifying potential experience for everything else.
Amazing work! Interesting that they go more terrestrial with maturity.
You say in this section that they might be shifting to feeding on larger prey items they have to cut up. Does that imply more of a “hawking” lifestyle? I assume it is still a mostly aerial animal even at larger body sizes?
You say in this section that they might be shifting to feeding on larger prey items they have to cut up. Does that imply more of a “hawking” lifestyle? I assume it is still a mostly aerial animal even at larger body sizes?
January 2, 2025 at 5:13 PM
Amazing work! Interesting that they go more terrestrial with maturity.
You say in this section that they might be shifting to feeding on larger prey items they have to cut up. Does that imply more of a “hawking” lifestyle? I assume it is still a mostly aerial animal even at larger body sizes?
You say in this section that they might be shifting to feeding on larger prey items they have to cut up. Does that imply more of a “hawking” lifestyle? I assume it is still a mostly aerial animal even at larger body sizes?
May you have a very merry Midwinter's Eve. May the #BoonSloth bring you many gifts and blessings upon your home.
#Dinotopia #Christmas
#Dinotopia #Christmas
December 25, 2024 at 1:55 AM
May you have a very merry Midwinter's Eve. May the #BoonSloth bring you many gifts and blessings upon your home.
#Dinotopia #Christmas
#Dinotopia #Christmas
"But the Allosaurus anax holotype isn't any better!"
We at least can confidently say it's a allosaurid, and it's consistent with Allosaurus while also having an interesting suite of features in its own right (lack of rugosities, reduced dorso-lateral ridge, etc.).
We at least can confidently say it's a allosaurid, and it's consistent with Allosaurus while also having an interesting suite of features in its own right (lack of rugosities, reduced dorso-lateral ridge, etc.).
December 22, 2024 at 10:10 PM
"But the Allosaurus anax holotype isn't any better!"
We at least can confidently say it's a allosaurid, and it's consistent with Allosaurus while also having an interesting suite of features in its own right (lack of rugosities, reduced dorso-lateral ridge, etc.).
We at least can confidently say it's a allosaurid, and it's consistent with Allosaurus while also having an interesting suite of features in its own right (lack of rugosities, reduced dorso-lateral ridge, etc.).
Just want to take a quick moment and remind all the dinofans exactly what they're defending when they yell at brick walls about the results of the new Saurophaganax paper.
December 22, 2024 at 10:10 PM
Just want to take a quick moment and remind all the dinofans exactly what they're defending when they yell at brick walls about the results of the new Saurophaganax paper.
I’m pretty sure this is the same individual, but still looking for confirmation. According to a friend who is more familiar cetaceans than I, the rostrum ridges suggest it could be a Bryde’s whale hybrid. Hard to tell without DNA, and unfortunately this individual has not been seen more recently.
December 20, 2024 at 5:26 PM
I’m pretty sure this is the same individual, but still looking for confirmation. According to a friend who is more familiar cetaceans than I, the rostrum ridges suggest it could be a Bryde’s whale hybrid. Hard to tell without DNA, and unfortunately this individual has not been seen more recently.
No #TurtleTuesday this week: busy prepping for the rush right before the holidays. Have an idea for next week's focus though...
In the meantime, try to spot #Dudley, the Western pond turtle (Emys marmorata) on display at the Natural History Museum of Los Angeles County @nhmla.bsky.social.
In the meantime, try to spot #Dudley, the Western pond turtle (Emys marmorata) on display at the Natural History Museum of Los Angeles County @nhmla.bsky.social.
December 17, 2024 at 11:57 PM
No #TurtleTuesday this week: busy prepping for the rush right before the holidays. Have an idea for next week's focus though...
In the meantime, try to spot #Dudley, the Western pond turtle (Emys marmorata) on display at the Natural History Museum of Los Angeles County @nhmla.bsky.social.
In the meantime, try to spot #Dudley, the Western pond turtle (Emys marmorata) on display at the Natural History Museum of Los Angeles County @nhmla.bsky.social.