Worsaae lab, UCPH

New life cycle hypothesis of the bone-eating worm Osedax having sexually predetermined larvae. Schematic drawing of Osedax development with sexually determined embryos developing into sexually determined larvae, female larvae having a gut, male larvae lacking one. Drawings are not scaled.

New addition to the spectacular life cycle of Osedax worms: sex of O. japonicus is genetically (not environmentally) determined since larvae show both morphological and transcriptomic signatures of gender. Might help us explain male dwarfism rdcu.be/eCHBe
@alicerouan.bsky.social @NorioMiyamoto

27.08.2025 13:59 — 👍 13    🔁 4    💬 0    📌 0

Join the best invertebrate event of 2025!
The official website for the 6th International Congress on Invertebrate Morphology (ICIM6) is now live! Check it out:
icim6.com
Thank you Felipe and colleagues for hosting this!

13.03.2025 18:50 — 👍 8    🔁 8    💬 0    📌 0

Micrognathozoa, or ‘little jaw animals’, are one of the ~32 evolutionarily independent lineages on the animal tree of life. This phylum contains some of the smallest animals reaching a maximum size of 150µm. Populations are found in Greenland, the Pyrenees Mountains, and a Subantarctic island. Despite this disjoint distribution, there is currently only one described species, Limnognathia maerski. After almost a decade of collecting effort, the Katrine Worsaae group here at BIO, UCPH, joining teams from USA, UK, France, and Spain, was able to collect samples from all three populations. With this new material, using advanced microscopy, single-cell transcriptomic techniques, and machine learning, we interrogate the relationships among populations, test species limits, and infer their biogeographic history for the first time. Although we find no morphological differences, genetic data distinguish the Subantarctic population as a separate species, here named Limnognathia desmeti. The distribution of this old freshwater phylum, Micrognathozoa, can only be explained by overseas dispersal which raises questions about potential dormant life stages and undiscovered populations.

Our paper describing the second species of Micrognathozoa, Limnognathia desmeti, is out: doi.org/10.1098/rspb... - big thanks to all coauthors, to Willem H. De Smet for finding this species, and to the Villum Foundation a.o. for supporting this project!

19.02.2025 15:06 — 👍 30    🔁 6    💬 1    📌 2

Priapulidans may have started out with microscopic body sizes, lack of caudal appendages, and internal fertilization; and macroscopic size and traits evolving secondarily. Where could this go 🫣... Scalidophora ancestrally meiofaunal? ... Ecdysozoans?

03.02.2025 21:34 — 👍 3    🔁 2    💬 0    📌 0

Priapulidans may have started out with microscopic body sizes, lack of caudal appendages, and internal fertilization; and macroscopic size and traits evolving secondarily. Where could this go 🫣... Scalidophora ancestrally meiofaunal? ... Ecdysozoans?

Big congrats to Jan Raeker and collaborators on this great paper:
doi.org/10.1016/j.ym...
The crowning glory moment of Jan's PhD :-) presenting an exiting phylogenomic study of Priapulida (penis worms) with unexpected predictions:

03.02.2025 21:32 — 👍 5    🔁 1    💬 1    📌 0

We looked into details of the stem cell system of catenulids. Surprisingly, it was very different from the canonical neoblast-based systems of other flatworms. What does it tell about the evolution of stem cells and regeneration? Check in our latest paper in @naturecomms.bsky.social:
bit.ly/3WK2ZzR

02.02.2025 16:07 — 👍 27    🔁 13    💬 1    📌 1

Join the "Zoomorphology & Evolution Meeting" at Dep. of Biology, UCPH, 13-19:30, 7 March 2025
Best wishes
Katrine Worsaae & Peter Funch

20.01.2025 21:10 — 👍 7    🔁 4    💬 1    📌 0

Join Denmark's excellent community of zoomorphologists and evolutionary biologists for a day of stimulating talks, networking, and discussions!
Let us know if you will participate and maybe give a talk, on your research or ’cool methods/facilities’ 🔬

18.01.2025 16:04 — 👍 3    🔁 1    💬 1    📌 1