Aaron Griffing
@aaronhgriffing.bsky.social
biologist | postdoc | evo devo | morphology | genomes | geckos | loud music & hot sauce enthusiast | he/him
https://aarongriffing.weebly.com/
#GeckoEvoDevo
https://aarongriffing.weebly.com/
#GeckoEvoDevo
Taken together, we show that there are distinct processes by which different squamate species build their lungs. Notably, the luminal pressure-driven stress ball morphogenesis in anoles appears to be derived, potentially due to the fact anoles develop in ovo so much faster than other squamates!
November 14, 2025 at 5:57 PM
Taken together, we show that there are distinct processes by which different squamate species build their lungs. Notably, the luminal pressure-driven stress ball morphogenesis in anoles appears to be derived, potentially due to the fact anoles develop in ovo so much faster than other squamates!
Notably, these structures aren’t being sculpted by smooth muscle like in mammal lungs. Rather, they are enriched for pMLC in the apical region of the epithelium, suggesting an apical-constriction mediated outgrowth. This developmental process is what bird lungs use to branch!
November 14, 2025 at 5:56 PM
Notably, these structures aren’t being sculpted by smooth muscle like in mammal lungs. Rather, they are enriched for pMLC in the apical region of the epithelium, suggesting an apical-constriction mediated outgrowth. This developmental process is what bird lungs use to branch!
We also found some very interesting aspects of chameleon lung development. Chameleon lungs exhibit multiple chambers and these bizarre projections called diverticulae. These chambers and diverticulae seem to grow out via concentrated cell proliferation.
November 14, 2025 at 5:54 PM
We also found some very interesting aspects of chameleon lung development. Chameleon lungs exhibit multiple chambers and these bizarre projections called diverticulae. These chambers and diverticulae seem to grow out via concentrated cell proliferation.
We decided to computationally simulate our hypothesized process: anoles expand their epithelium via luminal pressure while chams and geckos expand their epithelium via proliferation. This simulation suggested the epithelium would be thinner in anole lungs, and sure enough, that’s what we found!
November 14, 2025 at 5:53 PM
We decided to computationally simulate our hypothesized process: anoles expand their epithelium via luminal pressure while chams and geckos expand their epithelium via proliferation. This simulation suggested the epithelium would be thinner in anole lungs, and sure enough, that’s what we found!
This suggests geckos and chams don’t drastically increase luminal pressure to push the epithelium through the smooth muscle. EdU shows more cell proliferation in the epithelium of gecko and cham lungs than anoles, suggesting proliferation pushes the epithelium through the mesh in geckos and chams.
November 14, 2025 at 5:50 PM
This suggests geckos and chams don’t drastically increase luminal pressure to push the epithelium through the smooth muscle. EdU shows more cell proliferation in the epithelium of gecko and cham lungs than anoles, suggesting proliferation pushes the epithelium through the mesh in geckos and chams.
What we found in leopard gecko and chameleon lungs was also consistent in our opportunistic sampling of Italian wall lizard embryos.
November 14, 2025 at 5:45 PM
What we found in leopard gecko and chameleon lungs was also consistent in our opportunistic sampling of Italian wall lizard embryos.
We found that smooth muscle meshes show up in all three species, but what is really striking are the differences in inflation between anoles and the other two species. Aspect ratios are significantly different through development of the anole lung, but not in leopard geckos or chameleons.
November 14, 2025 at 5:44 PM
We found that smooth muscle meshes show up in all three species, but what is really striking are the differences in inflation between anoles and the other two species. Aspect ratios are significantly different through development of the anole lung, but not in leopard geckos or chameleons.
We aimed to investigate whether stress ball morphogenesis is conserved in other squamates. Additionally, we wanted to see if more complex lungs exhibit distinct patterns of lung morphogenesis. To do this, we looked at embryonic lungs of leopard geckos, brown anoles, and veiled chameleons!
November 14, 2025 at 5:42 PM
We aimed to investigate whether stress ball morphogenesis is conserved in other squamates. Additionally, we wanted to see if more complex lungs exhibit distinct patterns of lung morphogenesis. To do this, we looked at embryonic lungs of leopard geckos, brown anoles, and veiled chameleons!
Lungs are strikingly diverse and they formed in distinct ways between species. M Palmer previously showed that anoles generate their bumpy, balloon-like lungs via luminal pressure pushing the epithelium through a smooth muscle mesh (i.e. stress ball morphogenesis).
www.science.org/doi/10.1126/...
www.science.org/doi/10.1126/...
November 14, 2025 at 5:40 PM
Lungs are strikingly diverse and they formed in distinct ways between species. M Palmer previously showed that anoles generate their bumpy, balloon-like lungs via luminal pressure pushing the epithelium through a smooth muscle mesh (i.e. stress ball morphogenesis).
www.science.org/doi/10.1126/...
www.science.org/doi/10.1126/...
New paper out in @devdynamics.bsky.social on lizard lung development!
Project co-led w/ Kaleb Hill and also w/ @tonygamble.bsky.social @shylonatasha.bsky.social @aussiebiologist.bsky.social @bezbez.bsky.social @celestemnelson.bsky.social
anatomypubs.onlinelibrary.wiley.com/doi/10.1002/...
Project co-led w/ Kaleb Hill and also w/ @tonygamble.bsky.social @shylonatasha.bsky.social @aussiebiologist.bsky.social @bezbez.bsky.social @celestemnelson.bsky.social
anatomypubs.onlinelibrary.wiley.com/doi/10.1002/...
November 14, 2025 at 5:35 PM
New paper out in @devdynamics.bsky.social on lizard lung development!
Project co-led w/ Kaleb Hill and also w/ @tonygamble.bsky.social @shylonatasha.bsky.social @aussiebiologist.bsky.social @bezbez.bsky.social @celestemnelson.bsky.social
anatomypubs.onlinelibrary.wiley.com/doi/10.1002/...
Project co-led w/ Kaleb Hill and also w/ @tonygamble.bsky.social @shylonatasha.bsky.social @aussiebiologist.bsky.social @bezbez.bsky.social @celestemnelson.bsky.social
anatomypubs.onlinelibrary.wiley.com/doi/10.1002/...
New preprint from my postdoc work! Using fluorescent imaging, scRNA-seq, and ATAC-seq of mouse, anole, and chicken embryos, we provide evidence that birds have co-opted vascular smooth muscle to generate the pulmonary smooth muscle in their lungs. More on this later!
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
November 14, 2025 at 12:28 AM
New preprint from my postdoc work! Using fluorescent imaging, scRNA-seq, and ATAC-seq of mouse, anole, and chicken embryos, we provide evidence that birds have co-opted vascular smooth muscle to generate the pulmonary smooth muscle in their lungs. More on this later!
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
Pretty stoked that our article got the cover of the latest issue of @journalofanatomy.bsky.social!
Check it out here: doi.org/10.1111/joa....
Check it out here: doi.org/10.1111/joa....
November 5, 2025 at 7:09 PM
Pretty stoked that our article got the cover of the latest issue of @journalofanatomy.bsky.social!
Check it out here: doi.org/10.1111/joa....
Check it out here: doi.org/10.1111/joa....
New preprint from some of my postdoc work on lungs! Co-led with Kaleb Hill, we studied smooth muscle and epithelial development in lizard lungs. Stay tuned for more!
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
September 5, 2025 at 6:12 PM
New preprint from some of my postdoc work on lungs! Co-led with Kaleb Hill, we studied smooth muscle and epithelial development in lizard lungs. Stay tuned for more!
www.biorxiv.org/content/10.1...
www.biorxiv.org/content/10.1...
Sphaerodactylus geckos loom large in my mind (but sit small on my hand)
August 14, 2025 at 6:45 PM
Sphaerodactylus geckos loom large in my mind (but sit small on my hand)
So proud of my academic sibling @ecokatsully.bsky.social for defending her PhD today! Well done, Kat! To celebrate, here are some classy photos 🦋 🐛
July 17, 2025 at 8:43 PM
So proud of my academic sibling @ecokatsully.bsky.social for defending her PhD today! Well done, Kat! To celebrate, here are some classy photos 🦋 🐛
Why did hemibacula evolve? We aren't sure, but have some ideas. They appear to be the result of peramorphosis, like some of their skull features. If they have a function, we speculate they may be used to anchor during copulation or for female stimulation. This needs breeding experiments to confirm.
June 23, 2025 at 1:54 PM
Why did hemibacula evolve? We aren't sure, but have some ideas. They appear to be the result of peramorphosis, like some of their skull features. If they have a function, we speculate they may be used to anchor during copulation or for female stimulation. This needs breeding experiments to confirm.
Finally, we demonstrate that the lengths of different hemibaculum elements scale isometrically with body size. This is a relationship typical of organisms with pre-copulatory selection.
June 23, 2025 at 1:46 PM
Finally, we demonstrate that the lengths of different hemibaculum elements scale isometrically with body size. This is a relationship typical of organisms with pre-copulatory selection.
By looking at their development in a single population of Aristelliger praesignis, we demonstrate that hemibacula develop from a connective tissue structural precursor that eventually mineralizes. This all happens after this species is sexually mature.
June 23, 2025 at 1:42 PM
By looking at their development in a single population of Aristelliger praesignis, we demonstrate that hemibacula develop from a connective tissue structural precursor that eventually mineralizes. This all happens after this species is sexually mature.
We found very peculiar histology of hemibacula. Instead of true bone, like mammalian bacula, these appear to be mineralized connective tissue with epidermal barbs covering it. We also found alcian-positive cells that do not exhibit typical histology of cartilage. Very strange!
June 23, 2025 at 1:40 PM
We found very peculiar histology of hemibacula. Instead of true bone, like mammalian bacula, these appear to be mineralized connective tissue with epidermal barbs covering it. We also found alcian-positive cells that do not exhibit typical histology of cartilage. Very strange!
All species of Aristelliger have hemibacula, and their morphology corresponds to 3 putative clades that previous phylogenetic work supports.
June 23, 2025 at 1:36 PM
All species of Aristelliger have hemibacula, and their morphology corresponds to 3 putative clades that previous phylogenetic work supports.
Using these images I generated close to 10 years ago, and with the help of @danpaluh.bsky.social, Jon DeBoer, Juan Daza, @tonygamble.bsky.social, Tony Russell, and Aaron Bauer, we combined µCT, skeletal preps, and histology to study their evolutionary diversity and development.
June 23, 2025 at 1:33 PM
Using these images I generated close to 10 years ago, and with the help of @danpaluh.bsky.social, Jon DeBoer, Juan Daza, @tonygamble.bsky.social, Tony Russell, and Aaron Bauer, we combined µCT, skeletal preps, and histology to study their evolutionary diversity and development.
During my masters research at Villanova, I generated cleared and stained developmental series of Aristelliger to study their bizarre, hyperossified skulls. I would always notice these hemibacula and take photos.
June 23, 2025 at 1:28 PM
During my masters research at Villanova, I generated cleared and stained developmental series of Aristelliger to study their bizarre, hyperossified skulls. I would always notice these hemibacula and take photos.
Aristelliger are some of the only lizards that have mineralized structures in their hemipenes (i.e. hemibacula). They were initially described by Kluge in the 80s, but have otherwise been ignored in the literature. These are likely not homologous to the penile bones of some mammals (bacula).
June 23, 2025 at 1:21 PM
Aristelliger are some of the only lizards that have mineralized structures in their hemipenes (i.e. hemibacula). They were initially described by Kluge in the 80s, but have otherwise been ignored in the literature. These are likely not homologous to the penile bones of some mammals (bacula).