Cody Limber

List of 8 species names and observation dates next to a small thumbnail of my photograph. Here are the species: Deuteragenia sayi, Phytoplasma asteris, Chionea scita, Caenolampis robertsi, Anaptomecus longiventris, Galapaganus conwayensis, Nesocastolus, and Eumicrota socia.

List of another 8 species with pics: Eurythrips, Ischnodemus variegatus, Philodromus barrowsi, Aprostocetus fidius, Colaspis pseudofavosa, Mycosphaerella impatientis, Cymindis planipennis, and Heinrichiessa sanpetella.

If you're bored and use iNaturalist, here's a link to a tool that displays which of your observations were the first recorded for a taxon. I apparently have 16 (out of 3,395). I need to get out more. 🌿 #inaturalist #nature #insects #spiders glauberramos.github.io/inat/first-o...

As a mere feather biologist, it was such a privilege to get to see these books!! 10/10 can recommend tracing back your science to the oldest citation you can find

One of the copies of Origin bore this inscription which we figured out meant that Darwin had this book sent to his friend JD Dana. Dana was out of town in Italy, so Benjamin Silliman received the book instead. The citation is this review of Origin: ajsonline.org/article/66142

Our favorite detail was this fold-out tree, which is the only illustration in Origin, and has no doubt left its mark on how we visualize species' relationships

We also couldn't resist checking out a first edition copy of On the Origin of Species from 1859. Origin was much easier to read than Micrographia and felt more like an old book rather than something from a totally different era. Makes sense as it was half the age.

In addition to the beautiful feathers, this Hooke also coined the term "cells" which he observed looking at thin slices of cork.

the book open to the drawings of feathers

A close up of the drawing of feather barbules

It was a bit of a surprise that the drawings were on fold out pages that were often slightly larger than the rest of the book. The quality of the prints was also incredible

As a non-historian, it was pretty mind blowing to handle a book that's over 350 years old. We received some handling guidelines, but didn't have to wear gloves allowing us to experience the book in the same way someone from 1665 would have!

An image of the cover page of Micrographia

I posed recently about my recent obsession with Hooke's Micrographia (1665) and the incredible feather drawings it has. I really wanted to see an original copy and luckily, Yale has two! So, earlier this week, I headed down to the Beinecke Library with @mylestogo.bsky.social to check it out

small long fibres, such as are express'd

Okay last thing, what the heck is up with the long s?! It took me several minutes to parse this bit of text because of the combo of f, s, and long s.

Yes yes he's actually talking about the tons of barbs and barbules and the design of a higher power but if you squint your eyes a little bit, it's a perfect quote for starting my next feather cell type talk

an image of the text containing the quote mentioned

My favorite quote is almost about cell types and evolution "For there is hardly a large Feather in the wing of a Bird, but contains neer a million of distinct parts, and every one of them shap’d in a most regular & admirable form, adapted to a particular Design"

Of course, he doesn't get everything right. He is surprised not to find pores between the barbs and the rachis which he speculates should exist to transport nutrients to the barbs as they grow. Feathers actually grow from the base instead of branching from the tips like a tree

Hooke describes how barbules have hooklets and connect together to form a pennaceous feather. He also talks about how birds can "re-join and re-context" barbules that have been separated by "stroking the Feather or drawing it through its Bill"

It caught my eye because of the incredible descriptions and illustrations of feathers under a microscope which are just as impressive as any modern illustrations

Micrographia: or some physiological descriptions of minute bodies made by magnifying glasses with observations and inquiries thereupon

I bumped into a very cool reference today! Micrographia by Robert Hooke was published in 1665 and is basically a bunch of descriptions of things seen while looking through a microscope

One of my favorite parts of writing is remembering that the perfect citation exists and even remembering what one of the figures looks like but not remembering any of the key words that make finding the paper possible

This is incredible, congrats!! 🎉

Finally, if you’ve got a gene you’re interested in and want to know what cell types it’s expressed in, let me know!! AND if you think this work sounds really cool and interesting, I’ll be looking for postdocs next fall so let’s chat!

This work shows how we can connect development, morphology, and evolution. By tracing feather cell development and understanding feather cell type evolution, we can better understand how one of nature's coolest novelties - the feather - evolved!

A tree where the tips are different feather cell types

And finally, we made an evolutionary tree of feather cell types. Our tree, which is congruent with the evo-devo model of feather evolution, tells a new story about the homology of feather cells with the layers of the epidermis.

A circular plot showing signals coming from the marginal plate with their associated receptors in other cell types

Third, we looked at cell-cell signaling pathways and found that cell types only function in development of the feather play important roles in signaling the cells that eventually form the feather.

An image of a multicolored UMAP plot with RNA velocity arrows showing developmental trajectories

Second, we mapped developmental trajectories with RNA velocity. We find three trajectories corresponding to the sheath, the barb ridge, and the basal epithelium. This finding implies that the different layers of the skin develop on their own trajectories.

Some example in situ hybridizations on feather cross sections

First, we created a cell atlas for developing feathers. We used in situ hybridizations for marker genes and found that we can actually identify feather cell types based on their transcriptome profiles which should be helpful to anyone interested in using single cell sequencing on feathers!

Genetic Characterization of the Cell Types in Developing Feathers, and the Evolution of Feather Complexity We used single cell sequencing to investigate the cell types of developing chicken feathers. From these data, we are able to describe the transcriptional profile of feather cell types, look at their ....

My feather cell type paper is finally out! doi.org/10.1111/ede.... We’ve packed a ton of stuff into this paper but I’ll go through some highlights in this thread!

Archival artist rendering of a variety of birds and their feathers.

🪶 Feathers are complex, each one an elegant structure crafted through millions of years of evolution. As habitats shrink and climates continue to warm, understanding the why and how of colorful bird feathers could help us better protect them into the future: go.nhm.org/feathers-work

I'll be there!!

Presenting tomorrow at #Evol2025, swing by to hear about feathers, cell types, and a little teaser about pigmentation patterns!

This is super useful!! Any recommendations for places to go birding?

I hope to take a PhD student in the coming application cycle. Please reach out if you are interested in joining our lab in EEB at Yale, especially if interested in working on the natural history/ phylogenetics/ morphology/ population biology/ development/ genomics of siphonophores. dunnlab.org