Friday mystery object #216

I hope you all had an enjoyable Yuletide, I’ve certainly been glad of the excuse for a lie-in over the last few days.

The mystery object is a bit late today, but I hope you’ll forgive me in light of the general seasonal torpor.

Here’s a sternum that I’ve been puzzling over for a while – I can make a pretty good guess at the family it comes from, but I’m less sure of the species:

mystery216

I’d appreciate seeing what you think it might be – let’s see if we can work this out!