Cnidarian developmental mechanisms group

Great work, Anna!

I’m beyond excited to see our work published in Science Advances! 🎉

Deeply grateful to everyone involved — and especially to @pawelburkhardt.bsky.social for the great mentorship ✨

www.science.org/doi/10.1126/...

I'm thrilled to be co-teaching this wonderful course again this fall. Come join us at the MBL for a transformative experience!

Neural connectome of the ctenophore statocyst Volume EM and connectome reconstruction of the apical organ of a ctenophore combined with high-speed imaging reveals a neuronal coordination of balancer cilia in the gravisensory organ.

In @eLife: Neural connectome of the ctenophore statocyst https://doi.org/10.7554/eLife.108420
Version of record of our ctenophore nerve-net connectome paper.

Introducing a Clytia planula cell atlas, and demonstrating broad-level relations with medusa cells via another updated atlas. By @annaferraioli.bsky.social with @juliarmateu.bsky.social and collaborators in a project led by @rcply.bsky.social @biodev-vlfr.bsky.social www.biorxiv.org/content/10.6...

Two funded PhD positions investigating the evolution of sarcomeres @ibdm.bsky.social in @biancah0406.bsky.social and our lab, together with @cnidevo.bsky.social - Interested to explore how similar or different Jellyfish sarcomeres are to Drosophila or human ones?
www.ibdm.univ-amu.fr/ibdm_job/2-a...

Clytia sp. IZ-D, a newly identifed jellyfish species from Izushima Island, on the Pacific coast of Japan. Life-cycle diagram (top left) and images of each stage (top ight; a–f) of Clytia sp. IZ-D, which is morphologically very similar to the model species Clytia hemisphaerica. Magenta arrows in the gonozoid cartoon (c) indicate individual medusa buds. Arrows in the mature female medusa photo (e) point to the four gonads in the subumbrella. Bottom: Illustration of spawning regulation in Clytia sp. IZ-D. This species spawns every evening, unlike the closely related C. hemispharica, which spawns in the morning. Surprisingly, in both cases, it is sunrise, not sunset, that provides the temporal cue for spawning. In Clytia sp. IZ-D at 21°C, spawning occurs 14 hours after sunrise, regardless of sunset timing. A further surprise is that a 20-hour spawning rhythm is maintained even under constant light. Such autonomous circadian gamete release has not previously been reported in cnidarians (jellyfish, corals, or sea anemones). Future molecular studies using this Clytia species are expected to shed light on the mechanisms underlying light-controlled reproduction in marine organisms. Illustration by Ruka Kitsui.

#Jellyfish rely on light cues to help time their #gamete release. @momotsuyo.bsky.social &co reveal an additional autonomous #circadian mechanism that synchronizes gamete release, entrained to a 24-hr period by dark-to-light transition @plosbiology.org 🧪 plos.io/4btAwpY

Rhythmic ovulation in Clytia species. Top row: In Clytia hemisphaerica, the oocytes develop (blue arrow) becoming competent to respond to the maturation-inducing hormone (MIH), which triggers meiosis. MIH (red triangle) is released by neurosecretory cells in the gonads when they become exposed to light. After completion of meiosis (about 2 hours), the mature eggs are released. Ovulation (green square) lasts about 10 min. Since light is required to start a cycle, whose duration is regulated by the developmental programme, in C. hemisphaerica rhythmic ovulation is analogous to an hourglass. Bottom row: In Clytia sp.IZ-D light is required for synchronous development of the oocytes (blue arrow). However, the final maturation process, which makes them responsive to MIH, is gated by an unknown mechanism that likely operates individually in each oocyte (black-and-blue arrow). Light also drives the accumulation and progressive release of MIH. Meiosis begins when the oocytes reach the right maturation stage and MIH the right concentration. After about 2 hours ovulation begins, lasting about 60 min (green box). Together, the timing mechanisms controlling oocyte development and MIH release constitute an incipient clock. Two light-dark cycles are shown for reference.

In hydrozoan #jellyfish, the timing of gamete release is often coordinated by light. Ezio Rosato explores a @plosbiology.org study that elucidates a novel, endogenous clock-based mechanism that governs #egg release in a new species of jellyfish 🧪 Paper: plos.io/4btAwpY Primer: plos.io/49eTOya

An emerging clock mechanism in a hydrozoan jellyfish In hydrozoan jellyfish, the timing of gamete release is often coordinated by light. This primer discusses findings from a recent PLOS Biology article that elucidates a novel, endogenous clock-based me...

There's also a nice accompanying
Commentry piece by Ezio Rosato: dx.plos.org/10.1371/jour...

A light-entrained clock mechanism in a hydrozoan jellyfish synchronizes evening gamete release Jellyfish rely on light cues to help coordinate the timing of their gamete release. By characterizing a new species of jellyfish, this study reveals an additional autonomous circadian mechanism that s...

Now out in PLOS Biology- a novel clock mechanism regulating spawining in a newly-identified Clytia species
: dx.plos.org/10.1371/jour...

Happy New Year Marie-Emilie !

Happy 2026!
As usual now, jellyfish in Paris @clytia-vlfr.bsky.social

The Hydractinia Genome Project Portal: multi-omic annotation and visualization of Hydractinia genomic datasets AbstractMotivation. The colonial hydroid Hydractinia exhibits several unique biological properties, including its remarkable regenerative capacity and the

We've updated our Hydractinia Genome Project Portal! The site includes genomic, transcriptomic, and proteomic datasets, genome browsers, an interactive single-cell gene expression atlas, proteome-scale structure predictions, a custom BLAST interface, and more. Check it out! tinyurl.com/hydractinia

Come and do a PhD on 'Genome duplication, extinction and diversification in the evolution of flowering plants' with myself @jameswclark.bsky.social and Ilia Leitch @bristolpalaeo.bsky.social and join the @wgdip.bsky.social studying rediploidisation. Apply: tinyurl.com/26pmfvvc by Jan 8

Separation of the Early gastrula into oral and aboral halves shows that some neural cell tupes derive from aboral ectoderm, and others from i-cells

Drawing together findings from several projects over many years, we make a case that neural cell types in the Clytia larva have two embryological origins: i-cells and ectodermal.
bioRxiv 2025.11.17.688882; doi: doi.org/10.1101/2025...

Apply to join us! 🪼🪳🪱🐌

Tested in Clytia too - by @sassaf.bsky.social and @momotsuyo.bsky.social !

Is the deuterostome clade an artifact???

New paper with first author @anaserrasilva.bsky.social, Laura Piovani, Paschalis Natsidis and project co-led by Paschalia Kapli.

www.sciencedirect.com/science/arti...

Bravo @juliarmateu.bsky.social et @annaferraioli.bsky.social, merci à Richard Copley pour ce travail co-dirigée, et merci aux collaboratrices coralistes Isabelle Domart-Coulon (MNHN, Paris) et Núria Teixidó (LOV, et Ischia Marine Center, Stazione Zoologica Anton Dohrn)

for the moment the application site seems to be in french only www.embrc-france.fr/en/node/9845

Interested in visiting Villefranche, Roscoff or Banyuls marine stations? The EMBRC-France (www.embrc-france.fr) 8th Call for Projects is open. Deadline Sept 19 for stays by end of June 2026. Up to 42 person-days per project are covered, with access to EMBRC-France services, accommodation & catering.

Excited to finally see my PhD work published! We identified specialized cells in jellyfish and coral larvae with shared features and potentially linked to settlement regulation.

Our chromosome-scale genome assembly of Nanomia septata, a siphonophore - doi.org/10.1101/2025... . Much larger than many other cnidarian genomes, fewer chromosomes, and highly rearranged. No smoking gun for how they achieve complex colony-level organization. Great work Namrata Ahuja and friends!

Examples pf Coral larva aboral cell types

Careful scRNAseq and characterisation of cell types from larve of 3 cnidarian species uncovered shared features. This work can help understanding of animal nervous system evolution, and identified potential regulators of larval settlement !
Bravo @juliarmateu.bsky.social @annaferraioli.bsky.social

Aboral cell types of Clytia and coral larvae have shared features and link taurine to the regulation of settlement Larvae of jellyfish and corals have specialized sensory cells with shared features potentially linked to settlement regulation.

"Aboral cell types of Clytia and coral larvae have shared features and link taurine to the regulation of settlement" Kudos to Julia Ramon-Mateu and Anna Ferraioli @biodev-vlfr.bsky.social, and thanks to our collaborators for their coral larva expertise www.science.org/doi/10.1126/...

Sponges, ctenophores and the statistical significance of syntenies Shared fusions between ancestral chromosomal linkage groups have previously been used to support phylogenetic groupings, notably sponges with cnidarians and bilaterians to the exclusion of ctenophores...

New entry into the sponge/ctenophore debate.... Have the chromosome fusions separating ctenophores from all other animals been given too much weight? Beautifully clearly written paper covering complex arguments from @rcply.bsky.social.
www.biorxiv.org/content/10.1...

It's publication day of my first book: The Tree of Life. The tree of life is a time machine that can take us back 4 billion years to meet our most distant ancestor. It is the magic that lets us tell the origin stories, beginning with this ancient relative, of everything from mushrooms to man.

Cartoon of autonomous and light-modulated spwning cycles in Clytia IZ-D

Intriguing findings from our Sendai collaborators Ruka Kitsui and Ryusaku Deguchi. While C. hemispherica spawns at dawn, Clytia IZ-D species spawns at dusk. This is not triggered by dark but, unexpectedly, by light-mediated extension of an autonomously-running 20h cycle. doi.org/10.1101/2025...

The Hydractinia cell atlas reveals cellular and molecular principles of cnidarian coloniality - Nature Communications Here they generate a cell type atlas of the colonial cnidarian Hydractinia symbiolongicarpus, which reveals that distinct colony parts are mostly made from unique combinations of shared cell types, an...

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

🤝 @cnrscotedazur.bsky.social @sorbonne-universite.fr @clytia-vlfr.bsky.social

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