Aaron Griffing
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aaronhgriffing.bsky.social
Aaron Griffing
@aaronhgriffing.bsky.social
1K followers 450 following 120 posts
biologist | postdoc | evo devo | morphology | genomes | geckos | loud music & hot sauce enthusiast | he/him
https://aarongriffing.weebly.com/
#GeckoEvoDevo
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aaronhgriffing.bsky.social
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....
The December 2025 cover of Journal of Anatomy, depicting a CT scan skeleton of Aristelliger georgeensis with hemipenes featuring mineralized hemibacula
November 5, 2025 at 7:09 PM
aaronhgriffing.bsky.social
I was collecting #quail #embryos this morning and found an individual with albinism! Look at the lack of pigment in the retinal epithelium! Reminds me of finding a leopard #gecko embryo with the same condition during my PhD.
Two quail embryos. The individual on the left has dark pigment in it's eye while the individual on the right has no visible pigment in the eye. Two leopard gecko embryos. The individual on the left has dark pigment in it's eye while the individual on the right has no visible pigment in the eye.
September 25, 2025 at 3:00 PM
aaronhgriffing.bsky.social
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...
brightfield images of three lizard embryos of approximately the same developmental stage. Below each embryo image is an immunofluorescence image labeling E-cadherin (green) and alpha-smooth muscle actin (magenta) of their developing lungs
September 5, 2025 at 6:12 PM
aaronhgriffing.bsky.social
Sphaerodactylus geckos loom large in my mind (but sit small on my hand)
an adult miniaturized gecko, Sphaerodactylus macrolepis, sitting on top of my thumb
August 14, 2025 at 6:45 PM
aaronhgriffing.bsky.social
So proud of my academic sibling @ecokatsully.bsky.social for defending her PhD today! Well done, Kat! To celebrate, here are some classy photos 🦋 🐛
The Gamble Lab in front of the Rock N’ Roll Hall of Fame at Evolution 2022 Kat doing her best impression of a cocoon The first four Gamble Lab PhD students looking fancy at the Pabst Mansion My step dad, Kat Sullivan
July 17, 2025 at 8:43 PM
aaronhgriffing.bsky.social
Meme of a car labeled as "Mediterranean House Geckos" making a last minute decision to drive to Athens Georgia instead of Athens Greece
June 24, 2025 at 12:50 PM
aaronhgriffing.bsky.social
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.
A portrait of Aristelliger praesignis
June 23, 2025 at 1:54 PM
aaronhgriffing.bsky.social
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.
graphs illustrating log average hemibaculum element length as it relates to log snout-to-vent length. Slopes do not differ significantly from 1, suggesting isometry.
June 23, 2025 at 1:46 PM
aaronhgriffing.bsky.social
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.
An ontogenetic series of cleared and stained Aristelliger praesignis hemibacula, showing that they do not develop until after sexual maturity
June 23, 2025 at 1:42 PM
aaronhgriffing.bsky.social
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!
Figure 3 of the paper showing a Hall-Brundt Quadruple stain of Aristelliger hemibacula. Mineralized connective tissue is red, alcian positive tissue is blue, epidermis appears purple, and the non-mineralized connective tissue is bluish white.
June 23, 2025 at 1:40 PM
aaronhgriffing.bsky.social
All species of Aristelliger have hemibacula, and their morphology corresponds to 3 putative clades that previous phylogenetic work supports.
Figure 2 from the paper, showing the two subgenera of Aristelliger (Subgenus Aristelliger and Subgenus Aristelligella). Subgenus Aristelliger exhibit two mineralized elements per hemipenis lobe while subgenus Aristelligella exhibit only one element per lobe. Members of the A. praesignis and A. lar clades exhibit distinct morphology of the second hemibacula element.
June 23, 2025 at 1:36 PM
aaronhgriffing.bsky.social
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.
Figure 1 from the new paper showing everted hemipenes of Aristelliger, µCT rendering of hemibacula, and cleared and stained hemibacula.
June 23, 2025 at 1:33 PM
aaronhgriffing.bsky.social
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.
Dorsal views of developing parafrontals in cleared and stained Aristelliger hechti cleared and stained hemibacula of the same Aristelliger hechti
June 23, 2025 at 1:28 PM
aaronhgriffing.bsky.social
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).
An illustration of Aristelliger cochranae hemipenes and hemibacula, from Kluge (1982) An illustration of Aristelliger cochranae hemipenes and hemibacula, from Kluge (1982) µCT data of an Aristelliger georgeensis illustrating its skeleton and hemipenial mineralizations (hemibacula) in purple A µCT close up of the cloacal region of Aristelliger georgeensis illustrating the hemibacula in purple
June 23, 2025 at 1:21 PM
aaronhgriffing.bsky.social
As promised, SDB is over and it's time to talk about the most glorious lizards, croaking geckos (Aristelliger)
A photograph of Aristelliger praesignis, a dark green gecko with orange and white speckles, sitting on a branch.
June 23, 2025 at 1:13 PM
aaronhgriffing.bsky.social
Hell yeah, @mads100tist.bsky.social
Joaquin Navajas Acedo in his award talk at ICDB 2025 telling us “do not give them an INCH” in regards to people spreading misinformation and dismantling science
June 23, 2025 at 11:06 AM
aaronhgriffing.bsky.social
Pretty cool seeing both my developmental staging series at the @devdynamics.bsky.social table and #Lepidodactylus itself in San Juan for SDB! #2025SDB #2025ICDB #devbio #GeckoEvoDevo #mourninggecko
Some of the developmental staging series Developmental Dynamics has published, including Lepidodactylus lugubris A parthenogenetic lizard, the mourning gecko (Lepidodactylus lugubris), sitting on my thumb.
June 21, 2025 at 1:47 AM
aaronhgriffing.bsky.social
Excited to share a new #OA paper in @journalofanatomy.bsky.social detailing evolution and development of hemibacula: bizarre mineralized elements in hemipenes of croaking geckos.

onlinelibrary.wiley.com/doi/10.1111/...

#GeckoEvoDevo #Aristelliger
graphical abstract for our paper showing µCT images, histology, and illustrations of croaking gecko hemipenes hemibaculahttps://onlinelibrary.wiley.com/doi/10.1111/joa.70009
June 19, 2025 at 3:15 AM
aaronhgriffing.bsky.social
Going to #ICDB2025? Check out my poster on Thursday in the "Development and Evolution" section! Many of you may know me as a lizard biologist, but I'll be chatting about some of my postdoc work on comparative amniote development. Come see yet another reason why birds are so cool and weird! #SDB
The title of my poster: "Multi-omics analysis reveals a novel origin of pulmonary smooth muscle in the lungs of birds" When and where to see it: 19 June 2025, 2:00PM to 3:00PM at Poster A73 images: 1) mouse, anole, and chicken in a phylogenetic context with embryonic lung immunofluorescence 2) µCT of a chicken embryo with lung in blue 3) insets of in situ hybridization of chicken lung, single-cell RNA-seq, and ATAC-seq pile ups
June 14, 2025 at 3:23 PM
aaronhgriffing.bsky.social
Exciting to get to see embryos of new species in the lab! Here's an embryo of an Italian wall lizard (Podarcis siculus) from an introduced population here in NJ.
Lateral view of a lizard embryo, showcasing it's large eyes, developing brain and viscera, and limb buds.
May 20, 2025 at 9:11 PM
aaronhgriffing.bsky.social
Me every time there’s footage of a wall gecko used as b-roll on Love Island
#Tarentola
Leonardo DiCaprio pointing at a TV screen from “Once Upon a Time in Hollywood”
May 4, 2025 at 11:49 PM
aaronhgriffing.bsky.social
Forget how dark the world is for a moment and look at this spotted salamander who successfully crossed the road on its vernal pool migration last night.
A spotted salamander (Ambystoma maculatum) — a dark grey salamander with yellow spots — peering out from underneath fallen leaves.
March 6, 2025 at 2:26 PM
aaronhgriffing.bsky.social
So cool! That cleared and stained dolphin is incredible.
Plenty more gecko embryos where this came from!
#GeckoEvoDevo
Part of an embryonic series of the mourning gecko (Lepidodactylus lugubris). Earlier stage embryos are in the top left corner with later stages descending to the bottom right corner.
February 4, 2025 at 1:11 PM
aaronhgriffing.bsky.social
arboreal salamanders 🤝 arboreal geckos
portrait of a golden gecko (Gekko badenii) with visible blood sinuses in its adhesive toe pads
January 30, 2025 at 2:00 AM
aaronhgriffing.bsky.social
Very stoked to get the most recent cover of @sicbjournals.bsky.social! Here's a glorious, pad-reduced viper #gecko (Hemidactylus imbricatus). Check out our the article below and the rest of this awesome issue!

doi.org/10.1093/icb/...

#GeckoEvoDevo
The cover of Integrative & Comparative Biology, volume 64, number 5, 2024. The cover features a view from above of a viper gecko (Hemidactylus imbricatus), a brown gecko with large scales and tan speckles. A scanning electron micrograph (greyscale image) of an embryonic viper gecko hand, with a view of the palm. The toe pads and other scales are well-developed.
November 21, 2024 at 3:37 PM