The authors suggest that the cilia release the sheets via collective movement. Could there also be a role for release via a change in cilia-ECM interaction? Say, via MMP-mediated cleavage of integrins or other collagen-interacting proteins?

Could cilia have holdfast functions beyond mollusks? Collagen is pretty ancient (but not as old as cilia). For example, it looks like choanoflagellates have genes encoding collagen-like molecules (e.g., Uniprot A9V9M1 and A9V8A7). What do they do with them? Part of the theca?

Not to be overly critical, but it does seem like a missed opportunity for some proteomics of lamellae composition and immunofluorescence imaging of cell/cilia/collagen interactions.