On Friday I asked for your help with identifying this object:
There were a few interesting suggestions from beaks to bladders, but so far nothing really corresponds with the structure of this specimen. It’s very weird.
It looks like it’s probably from something aquatic, perhaps the ossified swim bladder of a fish, but I’m by no means sure of that.
I will see if I can read the notes written on the specimen under a UV light, but for now I have to admit that I am still stumped. Please let me know if you recognise what it is!
[N.B. from the discussion and links in the comments below, it emerges that this is the hyperostotic spine from the anal fin of a fish]