Splash tray - a bit missing!!

I noticed today that there was plastic hanging from the bottom of my car as I walked away from it. Closer inspection revealed that there is a small plastic panel underneath the engine that has totally disappeared (!) and the plastic behind it has snapped allowing a strip of it to hang loose. Has anyone got any thoughts as to what might have happened? I haven't hit anything ot caught any speedbumps etc and it was OK yesterday!! I wonder whether some d*ckhead has got underneath & ripped the small panel off..... :swear::swear:
 
the plastic under tray has a small lip and a small square section out of it near the gearbox...
 
There is a hole and a lip there for cooling the gearbox, sure it's not that you're seeing?
 
OK - so it looks like the small lip has been snapped off...maybe by a glancing blow from a speedbump or the baby rabbit that went under my car a few weeks ago!! I'm pretty sure the 'hole' is underneath the gearbox! Thanks for the reassurance!!