A colleague has found on the beach here in Kuwait what appears to be bone, but it has two closed loops pendant on which are two spikes via their own closed loops. It does not look to us as though this is anatomically possible!
There is a similar image here:
- but they do know either.
A hooped joint between two bones would have been tough enough (horseshoe crab tail, catfish barb, angler fish spine/illicium perhaps, but no); but three bones...!
The bones have been eroded, so those points are probably not original. It is perhaps surprising considering the erosion that the hoops have not broken.
One's thoughts goto shoulder blade - collar bone - humerus, but that's thinking in terms of mammal, in which there are no hoops (though with the acromion and coracoid, there are processes which one could imaging in modified form as hoops in some related animal; but then the other bones would have to develop matching hoops at their ends, which seems unlikely).
The closest I have come is catfish barb (eg. http://farm7.static.flickr.com/6151/6245080704_33912d8a6a.jpg), but I have found nothing really close.
So, I don't know.
But I did not want you to think nobody here was scratching their heads over this!
I hope some anatomist from deep in the addits of the NHM's collections will be able to solve this, for my sake as well as yours.
Thanks for the reply and the reassurance about head-scratching.
The points on the pendants are not fracture surfaces - they appear to be natural. The other is perhaps a bit worn.
The catfish example is suggestive, but shoulder blade just does not work in any sense. Even so, horseshoe crab tail, catfish barbs - these form closed interlinked loops?
I have wondered about the grooves on the pendants - they put me in mind of venom tracts, as in some snakes? But that goes nowhere, either.
So, we wait a bit ...
Thanks for posting this on the forum. I'm no expert, but these must be fish bones. No shoulder blade in fishes, since no limbs, but their skeleton is very intricate and extremely variable across groups. Just search for images like this one and you will be surprised - these bones will not seem so unusual now. The skull is made of many bones, but these you found may be from the spine. I'm just guessing, of course.