Dr. Karly E. Cohen

Priority deadline (Feb 16) for this years Fish Class at Friday Harbor is coming up quick! Get your applications in for what will be an amazing summer filled with great science, people, and tools!

Financial aid is available!!
@cmdonatelli.bsky.social @fishguy.bsky.social @karlycohen.bsky.social

Summer fish class at Friday Harbor Labs 🐟
5 weeks, field + lab, real projects.
Open to grads, postdocs, and undergrads. Financial aid available.
Apply: February 16, 2026
Reach out to @cmdonatelli.bsky.social @fishguy.bsky.social or @karlycohen.bsky.social with questions!
Details in the flyer ⬇️

There are a few courses that shaped the trajectory of my career. This is one of them. Take it if you can!

Fun opportunity for early career individuals at Friday Harbor Labs. Everyone I know who has taken or been involved in this course has a great time. Highly recommend.

Early students must take this!!

Summer fish class at Friday Harbor Labs 🐟
5 weeks, field + lab, real projects.
Open to grads, postdocs, and undergrads. Financial aid available.
Apply: February 16, 2026
Reach out to @cmdonatelli.bsky.social @fishguy.bsky.social or @karlycohen.bsky.social with questions!
Details in the flyer ⬇️

Have you read ICB's issue 6 yet?

with Applied #ecoimmunology in #wildlife health and #conservation

& authors
@schulzscience.bsky.social

@karlycohen.bsky.social Cohen

@thomsanger.bsky.social Sanger

@cmdonatelli.bsky.social Donatelli

Stacy Farina

and more!

academic.oup.com/icb/issue/65/6

Toothy armor, suction cups: Pacific spiny lumpsuckers persevere in Puget Sound The small, clumsy fish isn’t the strongest or fastest creature living in Puget Sound. But it has developed other tools to survive in rough waters.

Check out this really fun interview I got to work on with Mitch Borden on one of my favorite fish, the spiny lumpsucker!

www.knkx.org/science/2025...

Toothy armor, suction cups: Pacific spiny lumpsuckers persevere in Puget Sound The small, clumsy fish isn’t the strongest or fastest creature living in Puget Sound. But it has developed other tools to survive in rough waters.

Check out this really fun interview I got to work on with Mitch Borden on one of my favorite fish, the spiny lumpsucker!

www.knkx.org/science/2025...

NSF Graduate Research Fellowship Program (GRFP)

NSF GRFP solicitation is finally up. Life Sci deadline extended to Nov 10 but 2nd year grad students no longer eligible www.nsf.gov/funding/oppo...

Behold the Gloriously Weird Spotted Ratfish. It Has Teeth on Its Forehead for Sex Researchers have finally traced the origin of the spotted ratfish’s bizarre forehead teeth, which are used for mating

Behold the Gloriously Weird Spotted Ratfish. It Has Teeth on Its Forehead for Sex

New findings call into question one of the core assumptions about teeth. Adult male spotted ratfish have rows of teeth on top of their heads, in addition to those in their jaws. They use these teeth to grip females while mating. @karlycohen.bsky.social

More: www.washington.edu/news/2025/09...

New species alert! A Pascua goby from the Coral Sea. This genus now contains four species. Two from the Eastern Pacific and two from Australia, with more than 5,500km separating them. Lots of fun describing my second new species. #TeamFish #Fish
doi.org/10.3390/fish...

Behold the gloriously weird Spotted Ratfish. It has teeth on its forehead for sex. The teeth line a cartilaginous appendage called a tenaculum that in males can be erected and used to grasp a female during mating 🧪

Bumping to the Fishes! and Science feeds🐟🧪

Teeth outside the jaw: Evolution and development of the toothed head clasper in chimaeras | PNAS Chimaeras (Holocephali) are an understudied group of mostly deep-ocean cartilaginous fishes (Chondrichthyes) with unique characteristics that disti...

Super excited to share our new paper, out today @pnas.org 'Teeth outside the jaw: Evolution and development of the toothed head clasper in chimaeras' @karlycohen.bsky.social 👻🦈 🦷 www.pnas.org/doi/10.1073/...

Super cool!! What a weird fish #TeamFish

Ray Troll reconstruction of a fossil chimera.

CT scan of a spotted ratfish chimera.

Coolest fish is a ratfish and they have teeth on the head for mating. @karlycohen.bsky.social's most recent with a great Ray Troll piece of art.

🧪🐡

www.washington.edu/news/2025/09...

Article link here! www.pnas.org/doi/10.1073/...

This common fish has an uncommon feature: forehead teeth, used for mating New findings call into question one of the core assumptions about teeth. Adult male spotted ratfish, a shark-like species native to the eastern Pacific Ocean, have rows of teeth on top of their heads,...

New paper is officially out!
Ratfish have a second jaw on their foreheads - CT + histology show they’re real teeth, built from the same tissues and signals as oral teeth.

www.washington.edu/news/2025/09...

The incredible @shirel.bsky.social fills the room tonight for the FHL teaching us about how manta rays feed

Of course there would be no paper w/o my co-authors @fishyologist.bsky.social, Allyson Evans, Thaddaeus Buser, @calliehcrawford.bsky.social, @emilykane.bsky.social, and Matt Kolmann.

HUGE thanks to NSF for funding, @fishguy.bsky.social for the FHL fish class, & Scripps and OSU for their fish.

Digital 3D rendering of the head of Clinocottus globiceps. The jaw closing muscles are shown in red.

Scanning electron micrographs of the teeth and jaws of five sculpin species showing that Clinocottus globiceps and C. recalvus have blade like teeth rather than cones

Example of the thick lip in Clinocottus globiceps, shown with histological sectioning

One reason I love this project is because of how many different tools and techniques we used. Field collections, high-speed feeding videos, CT scans of the jaw bones and muscles, scanning electron micrographs of the teeth, and lip histology....truly a tour de force of fun science.

New fish paper! We found that Clinocottus globicpes eats anemones (weird!) using a novel wrestling behavior + strong jaws that likely started as adaptations for tearing algae. It also has thick skin that protects it from stinging cells. @jzoology.bsky.social 🐟🧪

DM for PDF.

doi.org/10.1111/jzo....

How could I forget to tag @karlycohen.bsky.social!!!

Repeated and widespread evolution of biofluorescence in marine fishes - Nature Communications Biofluorescence is widespread in fishes. Here, the authors compile data on biofluorescence presence across teleost fishes and demonstrate that it may have originally evolved in eels 112 million years ...

Hey look! Glowing fishes evolved over and over again. Lots of color of glow. @emilycarr.bsky.social led a team that included 5 FHL folks @jmhuie.bsky.social @lampichthys.bsky.social and @karlycohen.bsky.social.

The oldest glowy fish is an eel at 100MYA.
🧪

www.nature.com/articles/s41...

Repeated and widespread evolution of biofluorescence in marine fishes - Nature Communications Biofluorescence is widespread in fishes. Here, the authors compile data on biofluorescence presence across teleost fishes and demonstrate that it may have originally evolved in eels 112 million years ...

So excited to see this paper out! @jmhuie.bsky.social and I began looking at glowing fishes during the pandemic. @emilycarr.bsky.social turned it into amazing science! A great story about the evolution of glow

www.nature.com/articles/s41...

Four panel figure. A lateral CT scan of a frugivorous fish CT scan with an inset showing the jaws in frontal view. A 3D printed model of the upper and lower teeth opposing each other. The 3D printed models mounted in a materials testing system to allow food to be bitten. The load displacement curve that results from biting fruit in with the model jows.

Jack Rosen's paper on biting fruits and seeds is out in @royalsocietypublishing.org Interface. 3D models of pacu and piranha jaws cutting different prey. Pacus are 'better' at fruit. Maybe eating seeds drove the evolution of frugivory from piscivory.
🧪
royalsocietypublishing.org/doi/10.1098/...

@aineander.bsky.social: talented scientific artist with a kind soul! April runs the UChicago PaleoCT lab. Her beautiful work in scientific illustration/visualization helps researchers translate complex scientific concepts to visual media such as illustration, animation, & 3D prints

aprilneander.com

Wing Shape in Waterbirds: Morphometric Patterns Associated with Behavior, Habitat, Migration, and Phylogenetic Convergence Synopsis. Wing shape plays a critical role in flight function in birds and other powered fliers and has been shown to be correlated with flight performance

@stephanopteryx.bsky.social: studier of bird bones/anatomy and all round great person! Stephanie's current postdoc at UF involves 3D imaging the anatomy of bird lungs. Her previous PhD work on water bird wing shapes is available here:
doi.org/10.1093/iob/...