Aaron Griffing

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Preprint Alert
Ever thought that humans & chameleons look alike?
We follow chameleon development from fertilisation to oviposition & uncover the process through which they form an epiblast lumen that exhibits striking similarity to human embryos
#devbio #evodevo

www.biorxiv.org/content/10.1...

New Comparative Anatomy Textbook! Completely free to read and open access!

doi.org/10.59319/YHF...

Illustration showing a pair of Mirasaura perched on fern fronds. The green animals show their tall orange, brown and white crests while a small beetle flies over one of them

Here it is! Please welcome the AMAZING Mirasaura grauvogeli, a NEW MARVELOUS Drepanosaur published in NATURE today!
This astonishing reptile lived during the Middle Triassic in Europe and it possessed an amazing crest made of plume-like structures!

I was commissioned to bring it to life
#paleoart

Historical scientific illustration showing multiple detailed cross-sectional views of the skull and nasal cavity structure of a mole (genus Talpa). The image includes labeled anatomical features such as bone, cartilage, and sinus cavities. Each section is numbered and scaled, highlighting the complex development and structure of mammalian skull anatomy. The drawing is monochromatic with fine lines and shading for depth, emphasizing internal components like the nasal passages, cranial bones, and associated soft tissues. This plate from an 1885 publication by the Royal Society of London visually documents skull morphology in Mammalia for comparative anatomy studies.

🐾 On the structure and development of the skull in the mammalia /.
London: Royal Society of London, 1874-1885.

[Source]

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

So proud of my academic sibling @ecokatsully.bsky.social for defending her PhD today! Well done, Kat! To celebrate, here are some classy photos 🦋 🐛

Go work with Blair!

Nice Phrynosoma!

A close-up photo of the head and right hand and toes of a frog. The photo was taken through the side of a glass aquarium while the frog was climbing on the inside of the aquarium. The frog's hand is pressed against the glass, and shows three fingers and a thumb. At the tip of each digit is a large, oval disc that the frog uses to cling to the glass. The frog's belly is creamy white, and the troad is dark grey with small, white dots. The frog's head is turned slightly so that part of the mouth and bulgy eye are also visible.

Close-up of the toepads of the diploid edition of North America's gray treefrog (Hyla chrysoscelis). You can tell this one is a male from the loose, gray skin on his throat.

🚨🐸 Frog Nerds Assemble 🐸🚨

Recently we published a paper on the phylogenetics and taxonomy of Australia and New Guinea's tree frogs, the Pelodryadidae.

Link here: tinyurl.com/4udpmxsm

What does this mean for you Litoria-lovers?
There's a whole bunch more names to use!

Let me explain ...

A red flower on a green stem withe the words: BHL Call for support now open overlayed.

📢 The #BiodiversityHeritageLibrary is entering a bold new chapter – and we need your help! Today we release our official Call for Support. We’re seeking new hosts for BHL’s staff, infrastructure, and services. Learn more: blog.biodiversitylibrary.org/2025/06/tran... #BHLTransition #ILoveBHL

Foundations: please step up and take over the Biodiversity Heritage Library (BHL). This is an absolutely essential scanned archive of all of the old journals and books from the 1500s to about 1920. Has been indispensable for my research.
about.biodiversitylibrary.org/call-for-sup...

So disappointing. Biodiversity Heritage Library has been a CRUCIAL resource for my work and countless others.

Meet Estefany Caroline Guevara-Molina
iobopen.com/2025/06/30/m...
IOB coauthor of
Heat-Induced Hatching: Clarifying Effects of Hydration and Heating Rate on #Behavioral #Thermal Tolerance of Red-Eyed #Treefrog Embryos
Estefany Caroline Guevara-Molina et al
doi.org/10.1093/iob/...

#science #bio

ATAC‐seq in Emerging Model Organisms: Challenges and Strategies Principle of ATAC-seq (left), overview of arthropod species with published ATAC-seq data (middle), summary of experimental design (right).

You want to apply #ATACseq in your emerging model organism, but you don't know where to start? Is #ATACseq the best method for my research questions? Search no more! We got you covered with our new review: doi.org/10.1002/jez.... Excellent collaboration with @gevol.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

A portrait of Aristelliger praesignis

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.

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.

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.

An ontogenetic series of cleared and stained Aristelliger praesignis hemibacula, showing that they do not develop until after sexual maturity

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.

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.

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 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.

All species of Aristelliger have hemibacula, and their morphology corresponds to 3 putative clades that previous phylogenetic work supports.

Figure 1 from the new paper showing everted hemipenes of Aristelliger, µCT rendering of hemibacula, and cleared and stained hemibacula.

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.

Dorsal views of developing parafrontals in cleared and stained Aristelliger hechti

cleared and stained hemibacula of the same Aristelliger hechti

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.

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

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).

A photograph of Aristelliger praesignis, a dark green gecko with orange and white speckles, sitting on a branch.

As promised, SDB is over and it's time to talk about the most glorious lizards, croaking geckos (Aristelliger)

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

Hell yeah, @mads100tist.bsky.social

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.

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

Thanks, Antonia!

I'll be sure to do a proper thread once I'm back from SDB!

graphical abstract for our paper showing µCT images, histology, and illustrations of croaking gecko hemipenes hemibaculahttps://onlinelibrary.wiley.com/doi/10.1111/joa.70009

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

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

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